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Chinese Journal of Catalysis
2022, Vol. 43, No. 3
Online: 18 March 2022

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Cover: Yu and coworkers in their article on pages 571–583 described a general transition-metal-free photoinduced acetalation-pyridylation of alkenes using diethoxyacetic acid and cyanopyridine under mild conditions. Various functional group transformation, late-stage modification of drugs, and good in vitro antitumor activity indicate this protocol is of significance and potential for antitumor drug development.

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Special column on visible-light-driven catalytic organic synthesis

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Preface to special column on visible-light-driven catalytic organic synthesis Wei-Min He 2022, 43 (3):  547-547.  DOI: 10.1016/S1872-2067(21)63996-7 Abstract ( 166 )   HTML ( 235 )   PDF (468KB) ( 222 )

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Recent advances in radical-mediated transformations of 1,3-dienes Peng-Zi Wang, Wen-Jing Xiao, Jia-Rong Chen 2022, 43 (3):  548-557.  DOI: 10.1016/S1872-2067(21)63919-0 Abstract ( 1276 )   HTML ( 40 )   PDF (1310KB) ( 1309 )   1,3-Dienes are a class of easily accessible and versatile feedstock chemicals that can participate in a wide range of reactions to facilitate the synthesis of various valuable allylic compounds. In the past decades, radical methodology has emerged as a powerful tool for organic synthesis by virtue of the fact that diverse highly reactive radical species can usually be generated under mild, neutral and controlled conditions, and allow for rapid generation of molecular complexity. In this review, we critically illustrate the recent advances in the field of radical-mediated transformations of 1,3-dienes based on the different radical precursors and working modes. Wherever possible, particular emphasis is also put on the related mechanistic studies and synthetic applications.

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Conjugate addition-enantioselective protonation to forge tertiary stereocentres α to azaarenes via cooperative hydrogen atom transfer and chiral hydrogen-bonding catalysis Yaqi Tan, Yanli Yin, Shanshan Cao, Xiaowei Zhao, Guirong Qu, Zhiyong Jiang 2022, 43 (3):  558-563.  DOI: 10.1016/S1872-2067(21)63887-1 Abstract ( 190 )   HTML ( 11 )   PDF (976KB) ( 585 )   Supporting Information Cooperative hydrogen atom transfer and chiral hydrogen-bonding catalysis as a new platform for the asymmetric synthesis of azaarene derivatives is reported. By using a tetrabutylammonium decatungstate as the photocatalyst and a chiral phosphoric acid as the hydrogen-bonding catalyst, transformations of a variety of commercially available hydrocarbons and silanes with diverse α-branched 2-vinylazaarenes could efficiently experience a tandem radical conjugate addition and enantioselective protonation process, providing a convenient and fully atom economical approach to access a range of valuable enantioenriched α-tertiary azaarenes in high yields with good to excellent enantioselectivities (up to 93% ee). Through the direct use of tert-butyl methylcarbamate as the feedstock, this method enables a highly practical and concise synthesis of the enantiomerically pure medicinal molecule pheniramine (Avil).

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Photocatalyzed site-selective C(sp3)‒H sulfonylation of toluene derivatives and cycloalkanes with inorganic sulfinates Shaonan Zhang, Shi Cao, Yu-Mei Lin, Liyuan Sha, Cheng Lu, Lei Gong 2022, 43 (3):  564-570.  DOI: 10.1016/S1872-2067(21)63953-0 Abstract ( 140 )   HTML ( 12 )   PDF (962KB) ( 181 )   The development of practical methods for the direct and selective C(sp3)‒H functionalization of hydrocarbons is an attractive topic in synthetic chemistry. Although the radical-mediated hydrogen atom transfer (HAT) process has shown considerable potential in such reactions, it still faces fundamental problems associated with reactivity and selectivity. Herein, we report a convenient and economic approach to site-selective C(sp3)‒H sulfonylation via photo-induced HAT catalysis. Employing a conjugated polycyclic quinone as a direct HAT photocatalyst, commercially available inorganic sulfinates as the sulfonylation source, copper triflate as an inexpensive oxidant, a variety of toluene derivatives and cycloalkanes were converted into biologically and synthetically interesting sulfone products under mild conditions. The mechanistic studies reveal that the reaction sequence involves direct HAT-induced radical formation and a subsequent copper-mediated organometallic process for the C‒S bond formation. This method offers an appealing opportunity to furnish high value-added products from abundant hydrocarbon starting materials and inexpensive reagents.

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Transition-metal-free three-component acetalation-pyridylation of alkenes via photoredox catalysis Chun-Hua Ma, Yu Ji, Jie Zhao, Xing He, Shu-Ting Zhang, Yu-Qin Jiang, Bing Yu 2022, 43 (3):  571-583.  DOI: 10.1016/S1872-2067(21)63917-7 Abstract ( 419 )   HTML ( 8 )   PDF (1068KB) ( 402 )   Supporting Information A general transition-metal-free photoinduced acetalation-pyridylation of alkenes using diethoxyacetic acid and cyanopyridine was developed under mild conditions. By employing 4CzIPN as the photocatalyst and Cs2CO3 as the base, a diverse range of styrene derivatives and cyanopyridines worked well to give the desired products. The versatility of this method is highlighted by its application in the construction of various functional groups and the late-stage modification of drugs. Importantly, some of the synthesized compounds showed good in vitro antitumor activity, indicating that this protocol is of significance and potential for antitumor drug development.

Highlights

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Enzyme-powered micromotors based on hierarchical porous MOFs Lei Gan, Christian Doonan, Paolo Falcaro 2022, 43 (3):  584-585.  DOI: 10.1016/S1872-2067(21)63929-3 Abstract ( 303 )   HTML ( 19 )   PDF (697KB) ( 329 )

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CdS/polymer S-scheme H2-production photocatalyst and its in-situ irradiated electron transfer mechanism S. Wageh, Ahmed A. Al-Ghamdi, Omar A. Al-Hartomy, Maged F. Alotaibi, Linxi Wang 2022, 43 (3):  586-588.  DOI: 10.1016/S1872-2067(21)63925-6 Abstract ( 257 )   HTML ( 20 )   PDF (2156KB) ( 294 )

Perspective

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Photocatalytic conversion of waste plastics to low carbon number organic products Kaiyi Su, Huifang Liu, Chaofeng Zhang, Feng Wang 2022, 43 (3):  589-594.  DOI: 10.1016/S1872-2067(21)63885-8 Abstract ( 1028 )   HTML ( 45 )   PDF (1237KB) ( 711 )   As a great threat to all livings on earth, waste artificial plastics now are everywhere, from oceans to our cells [1]. The world cannot withstand the growing waste plastic in million tonnes every year, which has already caused environmental pollution and economic losses [2]. Besides the efforts for preparing novel plastics with the self-decomposition ability, methods are needed to clear away these waste plastics leftover from history or recycle well this organic carbon resource [3]. Photocatalysis is a potential solution for the conversion of waste plastics under mild conditions. In this perspective, we highlight the effect of photocatalytic approaches toward the generation of low carbon number organic products (Cn products, n ≤ 8) from waste plastics, which can proceed under an inert or aerobic atmosphere. Notably, critical analysis of the carbon source in products is necessary to reveal the active species for the C-X bonds (X = C, N, and O) cleavage of plastics. Finally, we outline potential avenues for further development of this emerging field to enhance the yield of Cn (n ≤ 8) products from waste plastics.

Account

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Photoelectrocatalysis for high-value-added chemicals production Yucong Miao, Mingfei Shao 2022, 43 (3):  595-610.  DOI: 10.1016/S1872-2067(21)63923-2 Abstract ( 394 )   HTML ( 17 )   PDF (8671KB) ( 521 )   Photoelectrocatalysis (PEC) is a promising approach that can convert renewable solar energy into chemical energy, while most concern is concentrated on PEC water splitting to obtain high-value-added fuel—hydrogen. In practice, more economic benefits can be produced based on PEC technique, such as H2O oxidative H2O2 synthesis, organic selective oxidation, organic pollutants degradation and CO2 reduction. Although there are plenty of excellent reviews focusing on the PEC water splitting system, the production of various high-value-added chemicals in PEC systems has not been discussed synthetically. This Account will focus on the production process of various high-value-added chemicals through PEC technology. The photoelectrode design, reaction environment and working mechanisms of PEC systems are also discussed in detail. We believe that this comprehensive Account of the expanded application of photoelectrocatalysis can add an inestimable impetus to the follow-up development of this technology.

Reviews

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Light alloying element-regulated noble metal catalysts for energy-related applications Hui Chen, Bo Zhang, Xiao Liang, Xiaoxin Zou 2022, 43 (3):  611-635.  DOI: 10.1016/S1872-2067(21)63899-8 Abstract ( 420 )   HTML ( 25 )   PDF (6604KB) ( 460 )   Noble metals have been widely used as heterogeneous catalysts because they exhibit high activity and selectivity for many reactions of both academic and industrial interest. The introduction of light atomic species (e.g., H, B, C, and N) into noble metal lattices plays an important role in optimizing catalytic performance by modulating structural and electronic properties. In this review, we present a general overview of the recent advances in the modification of noble metals with light alloying elements for various catalytic reactions, particularly for energy-related applications. We summarize the types, location, concentration, and ordering degree of light atoms as major factors in the performance of noble metal-based catalysts, with emphasis on how they can be rationally controlled to promote activity and selectivity. We then summarize the synthetic strategies developed to incorporate light elements and highlight the theoretical and experimental methods for understanding the alloying effects. We further focus on the wide usage of noble metal-based catalysts modified with different light alloying atoms and attempt to correlate the structural features with their catalytic performances. Finally, we discuss current challenges and future perspectives regarding the development of highly efficient noble metal-based catalysts modified with light elements.

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A review of defect engineering in two-dimensional materials for electrocatalytic hydrogen evolution reaction Tianmi Tang, Zhenlu Wang, Jingqi Guan 2022, 43 (3):  636-678.  DOI: 10.1016/S1872-2067(21)63945-1 Abstract ( 404 )   HTML ( 24 )   PDF (29051KB) ( 743 )   The exploration of efficient and earth-rich electrocatalysts for electrochemical reactions is critical to the implementation of large-scale green energy conversion and storage techniques. Two-dimensional (2D) materials with distinctive structural and electrochemical properties provide fertile soil for researchers to harvest basic science and emerging applications, which can be divided into metal-free materials (such as graphene, carbon nitride and black phosphorus) and transition metal-based materials (such as halogenides, phosphates, oxides, hydroxides, and MXenes). For faultless 2D materials, they usually exhibit poor electrochemical hydrogen evolution reaction (HER) activity because only edge sites can be available while the base surface is chemically inactive. Defect engineering is an effective strategy to generate active sites in 2D materials for improving electrocatalytic activity. This review presents feasible design strategies for constructing defect sites (including edge defects, vacancy defects and dopant derived defects) in 2D materials to improve their HER performance. The essential relationships between defect structures and electrocatalytic HER performance are discussed in detail, providing valuable guidance for rationally fabricating efficient HER electrocatalysts. The hydrogen adsorption/desorption energy can be optimized by constructing defect sites at different locations and by adjusting the local electronic structure to form unsaturated coordination states for efficient HER.

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Design and applications of hollow-structured nanomaterials for photocatalytic H2 evolution and CO2 reduction Xuli Li, Ning Li, Yangqin Gao, Lei Ge 2022, 43 (3):  679-707.  DOI: 10.1016/S1872-2067(21)63863-9 Abstract ( 384 )   HTML ( 21 )   PDF (15580KB) ( 683 )   Photocatalysis is considered a prospective way to alleviate the energy crisis and environmental pollution. It is therefore extremely important to design highly efficient photocatalysts for catalytic systems. In recent years, hollow-structured materials have attracted considerable interest for application in energy conversion fields owing to their large specific surface areas, improved light absorption, and shortened charge carrier transfer path. Because they contain inner and outer surfaces, hollow-structured materials can provide a superior platform for the deposition of other components. A number of hollow-structured hierarchical systems have been designed and fabricated in recent decades. It is important to rationally design and construct complex hierarchical structures. In this review, general preparation approaches for hollow-structured materials are presented, followed by a summary of the recent synthesis methods and mechanisms of typical hollow-structured materials for applications in the photocatalytic field. Complex hollow-structured hierarchical photocatalysts are classified into two types, hollow cocatalyst-based and hollow host photocatalyst-based, and the design principle and analysis of the photocatalytic reaction mechanism for photocatalytic H2 evolution and CO2 reduction are also introduced. The effects of hollow-structured materials have also been investigated. This review provides a reference for the rational construction of advanced, highly efficient photocatalytic materials.

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Multifunctional graphene-based composite photocatalysts oriented by multifaced roles of graphene in photocatalysis Yue-Hua Li, Zi-Rong Tang, Yi-Jun Xu 2022, 43 (3):  708-730.  DOI: 10.1016/S1872-2067(21)63871-8 Abstract ( 341 )   HTML ( 24 )   PDF (7374KB) ( 380 )   Graphene (GR), a single-layer carbon sheet with a hexagonal packed lattice structure, has displayed attractive potential and demonstrably become the research focus in artificial photocatalysis due to its enchanting properties in enhancing light absorption, electron transfer dynamics, and surface reactions. Currently, numerous efforts have shown that the properties of GR, which are closely correlated to the photocatalytic performance of GR-based composites are significantly affected by the synthesis methods. Herein, we first introduce the optimization strategies of GR-based hybrids and then elaborate the synthesis of GR-based composite photocatalysts oriented by manifold roles of GR in photoredox catalysis, containing photoelectron mediator and acceptor, improving adsorption capacity, regulating light absorption range and intensity, as well as macromolecular photosensitizer. Beyond that, a brief outlook on the challenges in this burgeoning research field and potential evolution strategies for enhancing the photoactivity of GR-based hybrids is presented and we anticipate that this review could provide some enlightenments for the rational construction and application of multifunctional GR-based composite photocatalysts.

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Recent advances in application of iron-based catalysts for COx hydrogenation to value-added hydrocarbons Junhui Liu, Yakun Song, Xuming Guo, Chunshan Song, Xinwen Guo 2022, 43 (3):  731-754.  DOI: 10.1016/S1872-2067(21)63802-0 Abstract ( 336 )   HTML ( 20 )   PDF (2928KB) ( 494 )   The widespread utilization of fossil fuels has caused an associated increase in CO2 emissions over the past few decades, which has resulted in global warming and ocean acidification. CO hydrogenation (Fischer-Tropsch synthesis, FTS) is considered a significant route for the production of liquid fuels and chemicals from nonpetroleum sources to meet worldwide demand. Conversion of CO2 with renewable H2 into valuable hydrocarbons is beneficial for reducing dependence on fossil fuels and mitigating the negative effects of high CO2 concentrations in the atmosphere. Iron-based catalysts exhibit superior catalytic performance in both FTS and CO2 hydrogenation to value-added hydrocarbons. The abundance and low cost of iron-based catalysts also promote their wide application in COx hydrogenation. This paper provides a comprehensive overview of the significant developments in the application of iron-based catalysts in these two fields. The active phases, promoter effect, and support of iron-based catalysts are discussed in the present paper. Based on understanding of these three essential aspects, we also cover recent advances in the design and preparation of novel iron-based catalysts for FTS and CO2 hydrogenation. Current challenges and future catalytic applications are also outlined.

Communication

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Stabilizing CuO photocathode with a Cu3N protection shell Xiang-dong Meng, Chao Zhen, Gang Liu, Hui-Ming Cheng 2022, 43 (3):  755-760.  DOI: 10.1016/S1872-2067(21)63894-9 Abstract ( 193 )   HTML ( 8 )   PDF (1833KB) ( 173 )   Supporting Information CuO, as a promising photocathode material, suffers from severe photocorrosion in photoelectrochemical water splitting applications. Herein, a Cu3N protection shell was used to protect the CuO photocathode for the first time to effectively suppress the photocorrosion of CuO. Consequently, the Cu3N-protected CuO photocathode shows improved stability, retaining 80% of its initial current density in a 20-min test, while only 10% of the initial current density can be retained for the bare photocathode. This work may provide an important strategy for using Cu3N shells to stabilize unstable photocathodes.

Articles

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Highly dispersed Cd cluster supported on TiO2 as an efficient catalyst for CO2 hydrogenation to methanol Jijie Wang, Jittima Meeprasert, Zhe Han, Huan Wang, Zhendong Feng, Chizhou Tang, Feng Sha, Shan Tang, Guanna Li, Evgeny A. Pidko, Can Li 2022, 43 (3):  761-770.  DOI: 10.1016/S1872-2067(21)63907-4 Abstract ( 779 )   HTML ( 44 )   PDF (2231KB) ( 703 )   Supporting Information The conversion of CO2 to methanol with high activity and high selectivity remains challenging owing to the kinetic and thermodynamic limitations associated with the low chemical reactivity exhibited by CO2. Herein, we report a novel Cd/TiO2 catalyst exhibiting a methanol selectivity of 81%, a CO2 conversion of 15.8%, and a CH4 selectivity below 0.7%. A combination of experimental and computational studies revealed that the unique electronic properties exhibited by the Cd clusters supported by the TiO2 matrix were responsible for the high selectivity of CO2 hydrogenation to methanol via the HCOO* pathway at the interfacial catalytic sites.

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Polyoxometalates-doped Bi2O3-x/Bi photocatalyst for highly efficient visible-light photodegradation of tetrabromobisphenol A and removal of NO Yingnan Zhao, Xing Qin, Xinyu Zhao, Xin Wang, Huaqiao Tan, Huiying Sun, Gang Yan, Haiwei Li, Wingkei Ho, Shun-cheng Lee 2022, 43 (3):  771-781.  DOI: 10.1016/S1872-2067(21)63843-3 Abstract ( 228 )   HTML ( 8 )   PDF (2436KB) ( 218 )   Supporting Information Bismuth-based photocatalysts are a class of excellent visible-light photocatalysts; however, their redox activity is relatively poor and the efficiency of photogenerated carrier separation is low, limiting their development and application in the field of photocatalysis. To address these issues, a series of polyoxometalate PW12O403--doped Bi2O3-x/Bi Schottky photocatalysts PW12@Bi2O3-x/Bi-n (PBOB-n, where n is the amount of NaBH4, i.e., 6, 12, 18, 24, and 48 mg) were prepared by a simple electrospinning/calcination/in-situ NaBH4 reduction method. In this composite photocatalyst, the doping of PW12 could effectively adjust the electronic structure of Bi2O3-x and improve its redox properties. As a shallow electron trap, PW12 promoted the separation of the photogenerated carriers. Furthermore, desirable Schottky junction between the metal Bi nanoparticles and PW12@Bi2O3-x further accelerated the separation of the photogenerated carriers. The synergistic effect of the aforementioned factors endowed PBOB-n with excellent photocatalytic activity. Among the samples, PBOB-18 exhibited superior photocatalytic activity. Under visible-light irradiation, 93.7% (20 mg catalyst) of 20 ppm tetrabromobisphenol A (TBBPA, 20 mL) was degraded in 60 min. Its activity was 4.4 times higher than that of Bi2O3. PBOB-18 also exhibited an ultrahigh photocatalytic performance for the removal of NO. Its removal rate (600 ppb) reached 83.3% in 30 min, making it one of the most active Bi-based photocatalysts. Furthermore, the photocatalytic mechanisms of PBOB-18 for TBBPA and NO have been proposed. This work provides a new direction and reference for the design of low-cost, efficient, stable, and versatile photocatalysts.

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Copper-doped zinc sulfide nanoframes with three-dimensional photocatalytic surfaces for enhanced solar driven H2 production Junmin Huang, Jianmin Chen, Wangxi Liu, Jingwen Zhang, Junying Chen, Yingwei Li 2022, 43 (3):  782-792.  DOI: 10.1016/S1872-2067(21)63864-0 Abstract ( 233 )   HTML ( 7 )   PDF (1567KB) ( 282 )   Supporting Information Solar-to-chemical energy conversion is perceived as one of the most potential solutions to the current energy and environmental crisis, yet requires major scientific endeavors on the development of efficient and sustainable photocatalysts. Remolding the composition and morphology of a semiconductor jointly for the purpose of improving photocatalysis efficiency remains challenging. Herein, we rationally fabricated Cu-doped ZnS nanoframes via a simple conjunct strategy of substitutional doping, chemical acidic etching, and sulfidation, aiming at enhancing the light utilization and charge separation/transfer efficiency for solar-light-driven hydrogen generation. Cu-doped zeolitic imidazolate framework-8 (ZIF-8) rhombic dodecahedrons are transformed to hollow Cu-ZIF-8 nanoframes converted to Cu-ZnS nanoframes with three-dimensional photocatalytic active surfaces via anisotropic chemical etching, which is further converted to Cu-ZnS nanoframes. By combining the merits of optimal heteroatom doping and frame-like open architecture, the obtained 1%Cu-doped ZnS nanoframe exhibits high photocatalytic activity under solar light irradiation with improved hydrogen production rate up to 8.30 mmol h-1g-1 and excellent stability in the absence of cocatalysts, which is significantly improved in comparison with those of the bare ZnS and Cu-ZnS with different morphologies. This work inspired by merging the merits of metal doping and anisotropic chemical etching may shed light on the rational design and fabrication of advanced photocatalysts.

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Oxidation of 2,5-bis(hydroxymethyl)furan to 2,5-furandicarboxylic acid catalyzed by carbon nanotube-supported Pd catalysts Zhenyu Li, Liyuan Huai, Panpan Hao, Xi Zhao, Yongzhao Wang, Bingsen Zhang, Chunlin Chen, Jian Zhang 2022, 43 (3):  793-801.  DOI: 10.1016/S1872-2067(21)63878-0 Abstract ( 220 )   HTML ( 6 )   PDF (1515KB) ( 235 )   Supporting Information The selective oxidation of 2,5-bis(hydroxymethyl)furan (BHMF) in this work was proven as a promising route to produce 2,5-furandicarboxylic acid (FDCA), an emerging bio-based building-block with wide application. Under ambient pressure, the modified carbon nanotube-supported Pd-based catalysts demonstrate the maximum FDCA yield of 93.0% with a full conversion of BHMF after 60 min at 60 °C, much superior to that of the traditional route using 5-hydroxymethylfurfural (HMF) as substrates (only a yield of 35.7%). The participation of PdHx active species with metallic Pd can be responsible for the encouraging performance. Meanwhile, a possible reaction pathway proceeding through 2,5-diformylfuran (DFF) and 5-formyl-2-furancarboxylic acid (FFCA) as process intermediates is suggested for BHMF route. The present work may provide new opportunities to synthesize other high value-added oxygenates by using BHMF as an alternative feedstock.

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Integration of Ru/C and base for reductive catalytic fractionation of triploid poplar Yiwei Fan, Helong Li, Shihao Su, Jinlei Chen, Chunquan Liu, Shuizhong Wang, Xiangya Xu, Guoyong Song 2022, 43 (3):  802-810.  DOI: 10.1016/S1872-2067(21)63881-0 Abstract ( 138 )   HTML ( 5 )   PDF (1833KB) ( 174 )   Supporting Information Lignin, which is the most recalcitrant component of lignocellulosic biomass, is also the most abundant renewable aromatic resource. Herein, reductive treatment of triploid poplar sawdust by the integration of catalytic Ru/C and a base, which afforded high yields of phenolic monomers from the lignin component and a solid carbohydrate pulp, is reported. The introduction of Cs2CO3 led to the generation of C2 side-chained phenols through the cleavage of Cβ-O and Cβ-Cγ bonds in β-O-4 units in addition to C3 side-chained phenols; the relationship between C2 and C3 was dependent on the base dosage. The reaction conditions, including base species, temperature, time, and H2 pressure, were optimized in terms of phenolic product distribution, delignification degree, and carbohydrate retention. The carbohydrate pulps generated from reductive catalytic fractionation in the presence of Cs2CO3 were more amenable to enzymatic hydrolysis, indicating that this treatment of biomass constituted the fractionation of biomass components together with the breakdown of biomass recalcitrance.

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A new strategy for the fabrication of covalent organic framework-metal-organic framework hybrids via in-situ functionalization of ligands for improved hydrogen evolution reaction activity Ling-Ling Zheng, Long-Shuai Zhang, Ying Chen, Lei Tian, Xun-Heng Jiang, Li-Sha Chen, Qiu-Ju Xing, Xiao-Zhen Liu, Dai-She Wu, Jian-Ping Zou 2022, 43 (3):  811-819.  DOI: 10.1016/S1872-2067(21)63892-5 Abstract ( 162 )   HTML ( 6 )   PDF (2500KB) ( 262 )   Supporting Information The development of novel porous materials have attracted significant attention owing to its possible application in several fields. In this study, we designed a novel covalent organic framework-metal-organic framework (COF-MOF) material through an in-situ ligand self-assembly method. The in-situ modified ligands not only act as nucleation sites to form Ti-MOF, but also as a channel to rapidly transfer photogenerated electrons without introducing additional chemical bonds. The photocatalytic hydrogen production rate achieved over B-CTF-Ti-MOF(1:1) was 1975 µmol·g-1·h-1 with an apparent quantum efficiency of 4.76%, which is 11.8 times higher than that of the pure CTF-1. In addition, compared with the sample prepared by separating the ligands (CTF-1/Ti-MOF), B-CTF-Ti-MOF shows excellent activity and stability. Finally, a reasonable photocatalytic mechanism was proposed using the results of electrochemical tests and spectral analyses. This study provides a universal method for the construction of highly efficient and stable COF/MOF materials with excellent properties.

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M/C3N4/AC (M = Au, Pt, Ru)-catalyzed acetylene coupling with ethylene dichloride: How effective are the bifunctionalities? Qing Yu, Shiyi Wang, Mengru Wang, Xiaoling Mou, Ronghe Lin, Yunjie Ding 2022, 43 (3):  820-831.  DOI: 10.1016/S1872-2067(21)63913-X Abstract ( 153 )   HTML ( 8 )   PDF (1440KB) ( 165 )   Supporting Information Acetylene coupling with ethylene dichloride, which uses both coal and oil resources, is attractive for sustainable PVC manufacturing. Herein, highly active and stable carbon nitride-based catalysts were developed by a novel pre-oxidation-pyrolysis process, affording unprecedented dehydrochlorination activity with good durability. The best-performing system was further modified with different precious metals (Au, Pt, and Ru) to promote the hydrochlorination chemistry between the in-situ formed hydrogen chloride and acetylene co-feed. The presence of metal centers intensifies the hydrochlorination activity but weakens the dehydrochlorination ability due to competitive adsorption between the two reactants at the metal sites. Superior coupling performance was achieved over C3N4/AC and single-atom Au/C3N4/AC catalysts in cascade reactors. Our results strongly suggest that dehydrochlorination is an essential step in the coupling reaction, and the activation of acetylene and ethylene dichloride molecules requires different active sites that should be engineered in future work.

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CO2 reduction reaction pathways on single-atom Co sites: Impacts of local coordination environment Haixia Gao, Kang Liu, Tao Luo, Yu Chen, Junhua Hu, Junwei Fu, Min Liu 2022, 43 (3):  832-838.  DOI: 10.1016/S1872-2067(21)63893-7 Abstract ( 225 )   HTML ( 113 )   PDF (1585KB) ( 211 )   Supporting Information Single-atom catalysts have been proposed as promising electrocatalysts for CO2 reduction reactions (CO2RR). Co-N4 active sites have attracted wide attention owing to their excellent CO selectivity and activity. However, the effect of the local coordination environment of Co sites on CO2 reduction reaction pathways is still unclear. In this study, we investigated the CO2 reduction reaction pathways on Co-N4 sites supported on conjugated N4-macrocyclic ligands with 1,10-phenanthroline subunits (Co-N4-CPY) by density functional theory calculations. The local coordination environment of single-atom Co sites with N substituted by O (Co-N3O-CPY) and C (Co-N3C-CPY) was studied for comparison. The calculation results revealed that both C and O coordination break the symmetry of the primary CoN4 ligand field and induce charge redistribution of the Co atom. For Co-N4-CPY, CO was confirmed to be the main product of CO2RR. HCOOH is the primary product of Co-N3O-CPY because of the greatly increased energy barrier of CO2 to *COOH. Although the energy barrier of CO2 to *COOH is reduced on Co-N3C-CPY, the desorption process of *CO becomes more difficult. CH3OH (or CH4) are obtained by further *CO hydrogenation reduction when using Co-N3C-CPY. This work provides new insight into the effect of the local coordination environment of single-atom sites on CO2 reduction reaction pathways.

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Spin regulation on (Co,Ni)Se2/C@FeOOH hollow nanocage accelerates water oxidation Yu Gu, Xiaolei Wang, Muhammad Humayun, Linfeng Li, Huachuan Sun, Xuefei Xu, Xinying Xue, Aziz Habibi-Yangjeh, Kristiaan Temst, Chundong Wang 2022, 43 (3):  839-850.  DOI: 10.1016/S1872-2067(21)63922-0 Abstract ( 184 )   HTML ( 7 )   PDF (2714KB) ( 201 )   Supporting Information Spin engineering is recognized as a promising strategy that modulates the association between d-orbital electrons and the oxygenated species, and enhances the catalytic kinetics. However, few efforts have been made to clarify whether spin engineering could make a considerable enhancement for electrocatalytic water oxidation. Herein, we report the spin engineering of a nanocage-structured (Co,Ni)Se2/C@FeOOH, that showed significant oxygen evolution reaction (OER) activity. Magnetization measurement presented that the (Co,Ni)Se2/C@FeOOH sample possesses higher polarization spin number (μb = 6.966 μB/f.u.) compared with that of the (Co,Ni)Se2/C sample (μb = 6.398 μB/f.u.), for which the enlarged spin polarization number favors the adsorption and desorption energy of the intermediate oxygenated species, as confirmed by surface valance band spectra. Consequently, the (Co,Ni)Se2/C@FeOOH affords remarkable OER product with a low overpotential of 241 mV at a current of 10 mA cm-2 and small Tafel slope of 44 mV dec-1 in 1.0 mol/L KOH alkaline solution, significantly surpassing the parent (Co,Ni)Se2/C catalyst. This work will trigger a solid step for the design of highly-efficient OER electrocatalysts.

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Hierarchical AgAu alloy nanostructures for highly efficient electrocatalytic ethanol oxidation Caiqin Wang, Danil Bukhvalov, M. Cynthia Goh, Yukou Du, Xiaofei Yang 2022, 43 (3):  851-861.  DOI: 10.1016/S1872-2067(21)63895-0 Abstract ( 289 )   HTML ( 17 )   PDF (2684KB) ( 265 )   Supporting Information The ethanol oxidation reaction is a significant anodic reaction for direct alcohol fuel cells. The most commonly used catalysts for this reaction are Pt-based materials; however, Pt-based electrocatalysts cause carbon monoxide poisoning with intermediates before the complete transformation of alcohol to CO2. Herein, we present hierarchical AgAu bimetallic nanoarchitectures for ethanol electrooxidation, which were fabricated via a partial galvanic reduction reaction between Ag and HAuCl4. The ethanol electrooxidation performance of the optimal AgAu nanohybrid was increased to 1834 mA mg‒1, which is almost 10 times higher than that of the pristine Au catalyst (190 mA mg‒1) in alkaline solutions. This was achieved by introducing Ag into the Au catalyst and controlling the time of the replacement reaction. The heterostructure also presents a higher current density than that of commercial Pt/C (1574 mA mg‒1). Density functional theory calculations revealed that the enhanced activity and stability may stem from unavoidable defects on the surface of the integrated AgAu nanoarchitectures. Ethanol oxidation reactions over these defects are more energetically favorable, which facilitates the oxidative removal of carbonaceous poison and boosts the combination with radicals on adjacent Au active sites.

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CO2 hydrogenation selectivity shift over In-Co binary oxides catalysts: Catalytic mechanism and structure-property relationship Longtai Li, Bin Yang, Biao Gao, Yifu Wang, Lingxia Zhang, Tatsumi Ishihara, Wei Qi, Limin Guo 2022, 43 (3):  862-876.  DOI: 10.1016/S1872-2067(21)63870-6 Abstract ( 261 )   HTML ( 23 )   PDF (2497KB) ( 332 )   Supporting Information The hydrogenation of CO2 into methanol has attracted much attention and In2O3 is a promising catalyst. Introducing metal elements into In2O3 (M/In2O3) is one of the main strategies to improve its performance. However, its mechanism and active sites remain unclear and need to be further elucidated. Here, the noble-metal-free Inx-Coy oxides catalysts were prepared. Much-improved performance and obvious product selectivity shift were observed. The optimized catalyst (In1-Co4) (9.7 mmol gcat-1 h-1) showed five times methanol yields than pure In2O3 (2.2 mmol gcat-1 h-1) (P = 4.0 MPa, T = 300 °C, GHSV = 24000 cm3STP gcat-1 h-1, H2:CO2 = 3). And the cobalt-catalyzed CO2 methanation activity was suppressed, although cobalt was most of the metal element. To unravel this selectivity shift, detailed catalysts performance evaluation, together with several in-situ and ex-situ characterizations, were employed on cobalt and In-Co for comparative study. The results indicated CO2 hydrogenation on cobalt and In-Co catalyst both followed the formate pathway, and In-Co reconstructed and generated a surface In2O3-enriched core-shell-like structure under a reductive atmosphere. The enriched In2O3 at the surface significantly enhanced CO2 adsorption capacity and well stabilized the intermediates of CO2 hydrogenation. CO2 and carbon-containing intermediates adsorbed much stronger on In-Co than cobalt led to a feasible surface C/H ratio, thus allowing the *CH3O to desorb to produce CH3OH instead of being over-hydrogenated to CH4.

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Insights into effects of ZrO2 crystal phase on syngas-to-olefin conversion over ZnO/ZrO2 and SAPO-34 composite catalysts Zhaopeng Liu, Youming Ni, Zhongpan Hu, Yi Fu, Xudong Fang, Qike Jiang, Zhiyang Chen, Wenliang Zhu, Zhongmin Liu 2022, 43 (3):  877-884.  DOI: 10.1016/S1872-2067(21)63908-6 Abstract ( 162 )   HTML ( 8 )   PDF (1922KB) ( 209 )   Supporting Information The utilization of metal oxide-zeolite catalysts in the syngas-to-olefin reaction is a promising strategy for producing C2-C4 olefins from non-petroleum resources. However, the effect of the crystal phase of metal oxides on the catalytic activity of these oxides is still ambiguous. Herein, typical metal oxides (ZnO/ZrO2) with different crystal phases (monoclinic (m-ZrO2) and tetragonal (t-ZrO2)) were employed for syngas conversion. The (ZnO/m-ZrO2+SAPO-34) composite catalyst exhibited 80.5% selectivity for C2-C4 olefins at a CO conversion of 27.9%, where the results are superior to those (CO conversion of 16.4% and C2-C4 olefin selectivity of 76.1%) obtained over (ZnO/t-ZrO2+SAPO-34). The distinct differences are ascribed to the larger number of hydroxyl groups, Lewis acid sites, and oxygen defects in ZnO/m-ZrO2 compared to ZnO/t-ZrO2. These features result in the formation of more formate and methoxy intermediate species on the ZnO/m-ZrO2 oxides during syngas conversion, followed by the formation of more light olefins over SAPO-34. The present findings provide useful information for the design of highly efficient ZrO2-based catalysts for syngas conversion.

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Non-catalytic, instant iridium (Ir) leaching: A non-negligible aspect in identifying Ir-based perovskite oxygen-evolving electrocatalysts Qi Zhang, Hui Chen, Lan Yang, Xiao Liang, Lei Shi, Qing Feng, Yongcun Zou, Guo-Dong Li, Xiaoxin Zou 2022, 43 (3):  885-893.  DOI: 10.1016/S1872-2067(21)63983-9 Abstract ( 156 )   HTML ( 8 )   PDF (2347KB) ( 239 )   Supporting Information The large-scale application of proton exchange membrane water electrolysis technology requires the development of high-performance oxygen evolution electrocatalysts with as little iridium (Ir) as possible. Ir-based double perovskite oxides (A2B’IrO6; A = alkaline, alkaline-earth, or rare-earth elements; B’ = transition metal or rare-earth elements) represent a class of oxides with great potential to replace the commercial catalyst IrO2. However, the structural evolution of Ir-based double perovskite oxides in electrolytes is incompletely understood, and foundational knowledge of the design principle of the “ideal” material is lacking. In this work, we report the unexpected phenomenon of instant Ir leaching from Ir-based double perovskite oxides in acid under non-catalytic conditions and discuss the implications of this phenomenon for mechanism investigation and material identification. Some well-known Ir-based double perovskite oxides, such as Ba2PrIrO6 and Sr2YIrO6, undergo instantaneous Ir leaching when they come into contact with acidic electrolytes. The Ir-leaching process is found to be non-persistent and non-thermodynamically determined, and its extent is correlated with the leaching of other B’-site elements in the perovskite oxides. Based on this observation, we revisit the Ir dissolution-precipitation process for surface IrOx formation during the perovskite-electrolyzed oxygen evolution reaction, emphasizing the non-negligible role of Ir species owing to acid corrosion in the electrolyte. Finally, we modify a screening protocol for low-Ir oxygen evolution electrocatalysts and propose an instant acid corrosion test as an indispensable process to evaluate the structural stability of potential catalysts.