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    Chinese Journal of Catalysis
    2024, Vol. 67
    Online: 18 December 2024

    Cover: The research groups led by Siyu Yao and Zhiguo Zhang from Zhejiang University have developed a heterojunction catalyst named Ag-AgBr/ZnO. This catalyst facilitates the separation of photogenerated electron-hole pairs through the type-II heterojunction formed between AgBr and ZnO, significantly enhancing the photocatalytic efficiency. Furthermore, the migration of photogenerated holes from ZnO to AgBr attenuates their oxidation potential, resulting in a moderate oxidation capacity. Consequently, the catalyst effectively prevents overoxidation of products and demonstrates outstanding performance in the selective photooxidation of methane to C1 oxygenates. Read more about the article behind the cover on page 61–70.
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    Efficient low-temp direct air capture methods
    Hao Zhang, Menghui Qi, Yong Wang
    2024, 67:  1-3.  DOI: 10.1016/S1872-2067(24)60169-5
    Abstract ( 182 )   HTML ( 13 )   PDF (925KB) ( 94 )  
    Review
    Porousizing catalysts for boosting CO2 electroreduction
    Xiaoyu You, Caoyu Yang, Xinwei Li, Zhiyong Tang
    2024, 67:  4-20.  DOI: 10.1016/S1872-2067(24)60147-6
    Abstract ( 354 )   HTML ( 37 )   PDF (7421KB) ( 212 )  

    Facing soaring global energy demand and intensifying environmental problems, the search for sustainable energy alternatives has become imperative. The efficient conversion of carbon dioxide (CO2), one of the primary greenhouse gases, plays the crucial role in mitigating global climate change. The electrocatalytic CO2 reduction reaction (eCO2RR) provides an effective solution for its conversion into high-value-added chemicals, promoting the development of the carbon cycle and green chemistry. Porous materials of distinctive physicochemical properties have demonstrated substantial potential in eCO2RR. In this review, various strategies of porousizing catalysts for boosted eCO2RR are briefly summarized. Subsequently, the functionalities of porous materials including enrichment effect, modulating microenvironmental pH, stabilizing key species, facilitating mass transfer and tuning the nature of active sites to improve the efficiency and selectivity of eCO2RR are categorized. Furthermore, we discuss the principal challenges confronting current electrocatalytic systems and propose future research directions. Insights from this review are expected to benefit broad communities of chemical and material research for rationalizing porous electrocatalysts and optimizing eCO2RR performances.

    Non-derivatized metal-organic framework nanosheets for water electrolysis: Fundamentals, regulation strategies and recent advances
    Yingjie Guo, Shilong Li, Wasihun Abebe, Jingyang Wang, Lei Shi, Di Liu, Shenlong Zhao
    2024, 67:  21-53.  DOI: 10.1016/S1872-2067(24)60153-1
    Abstract ( 158 )   HTML ( 13 )   PDF (13913KB) ( 65 )  

    Water splitting powered by clean electricity is a sustainable and promising approach to produce green hydrogen. Currently, noble metal (e.g. Iridium, Ruthenium, Platinum)-based catalysts are most widely used for water splitting electrolysis. However, noble metal-based catalysts often suffer from multiple disadvantages, including high cost, low selectivity and poor durability. The emergence of metal-organic framework nanosheets (MOFNSs) attracts significant attention due to their unique advantages. Here, a concise, yet comprehensive and critical, review of recent advances in the field of MOFNSs is provided. This review explains the fundamental oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) catalytic mechanisms as well as key characterization techniques for the structure-activity relationship study are discussed. Moreover, it discusses efficient design strategies and the brief research advances of MOFNSs in HER, OER, and bifunctional electrocatalysis, along with some challenges and opportunities.

    Communication
    Site-selective benzylic C-H oxidation through mediated electrolysis
    Yi-Fan Xi, Rui-Xing Gao, Ping Fang, Ya-Ping Han, Cong Ma, Tian-Sheng Mei
    2024, 67:  54-60.  DOI: 10.1016/S1872-2067(24)60139-7
    Abstract ( 250 )   HTML ( 14 )   PDF (1241KB) ( 97 )  
    Supporting Information

    A novel strategy for site-selective benzylic C-H oxidation has been developed through mediated electrolysis. A bulky maleimide N-oxyl radical (MINO) generated by proton-coupled electrochemical oxidation of N-hydroxymaleimide (NHMI), serves as a hydrogen atom-transfer mediator. Good-to-excellent site selectivity was observed among different substrates, providing a practical approach for site-selective benzylic C-H oxidation. Additionally, the hydrogen-atom transfer mechanism for C-H electrochemical oxidation allows the oxidation to proceed at much lower anode potentials relative to direct electrolysis and with minimal reliance on the substrate's electronic properties.

    Article
    Selective photooxidation of methane to C1 oxygenates by constructing heterojunction photocatalyst with mild oxidation ability
    Hantao Gong, Caihao Deng, Peipei He, Mingjie Liu, Yiliang Cai, Yiwen Yang, Qiwei Yang, Zongbi Bao, Qilong Ren, Siyu Yao, Zhiguo Zhang
    2024, 67:  61-70.  DOI: 10.1016/S1872-2067(24)60136-1
    Abstract ( 253 )   HTML ( 15 )   PDF (3935KB) ( 92 )  
    Supporting Information

    Selective photocatalytic aerobic oxidation of methane to value-added chemicals offers a promising pathway for sustainable chemical industry, yet remains a huge challenge owing to the consecutive overoxidation of primary products. Here, a type II heterojunction were constructed in Ag-AgBr/ZnO to reduce the oxidation potential of stimulated holes and prevent the undesirable CH4 overoxidation side reactions. For photocatalytic oxidation of methane under ambient temperature, the products yield of 1499.6 μmol gcat-1 h-1 with a primary products selectivity of 77.9% was achieved over Ag-AgBr/ZnO, which demonstrate remarkable improvement compared to Ag/ZnO (1089.9 μmol gcat-1 h-1, 40.1%). The superior activity and selectivity result from the promoted charge separation and the redox potential matching with methane activation after introducing AgBr species. Mechanism investigation elucidated that the photo-generated holes transferred from the valence band of ZnO to that of AgBr, which prevent H2O oxidation and enhance the selective generation of •OOH radical.

    Dynamic proton migration in dual linkage-engineered D-π-A system for photosynthesis H2O2 generation
    Zhihan Yu, Dainan Zhang, Chenbing Ai, Jianjun Zhang, Quanjun Xiang
    2024, 67:  71-81.  DOI: 10.1016/S1872-2067(24)60159-2
    Abstract ( 129 )   HTML ( 2 )   PDF (2188KB) ( 45 )  
    Supporting Information

    Accelerated charge migration and proton transfer to the reaction site are critical factors for improving photocatalytic efficiency. However, realizing both simultaneously is challenging because of the sluggish water (proton source) oxidation kinetics and interdependent redox reactions. Herein, we design an imide and hydrogen bond to connect carbon nitride ports of the D-π-A system with the dual-engineered linkages. The system uses an acetylene functional group and an imidazole ring as spatially separated water oxidation and oxygen reduction reaction (ORR) catalytic centers for photogenerated charge separation, respectively. The imine bond is a bridge grafted to the oxidation site to act as a hydrogen proton trap, and the hydrogen bond formed between reduction site and carbon nitride is used as the channel for instantaneous proton delivery to the reduction center. In situ characterization confirms that the linking sites protonation optimizes the pathway of ORR to H2O2 and facilitates the *OOH intermediates generated. It is concluded that proton transport plays a critical role in optimizing photocatalytic H2O2 production. Our work provides a strategy to improve dynamic proton transfer mechanisms.

    Silicalite-1 zeolite nanosheets with rich H-bonded silanols for boosting vapor-phase Beckmann rearrangement: One-pot synthesis and theoretical investigation
    Tianming Zai, Wei Chen, Jiamin Yuan, Ye Ma, Qinming Wu, Xianfeng Yi, Zhiqiang Liu, Xiangju Meng, Weiliao Liu, Na Sheng, Han Wang, Anmin Zheng, Feng-Shou Xiao
    2024, 67:  82-90.  DOI: 10.1016/S1872-2067(24)60160-9
    Abstract ( 168 )   HTML ( 8 )   PDF (1632KB) ( 61 )  
    Supporting Information

    Design and preparation of highly efficient zeolite catalysts for gas-phase Beckmann rearrangement of cyclohexanone oxime to caprolactam are attractive but still challenging. Herein, we show a one-pot synthesis of silicalite-1 zeolite nanosheets with rich H-bonded silanols. The key to this success is the use of urea in the synthetic system. Catalytic tests of cyclohexanone oxime gas-phase Beckmann rearrangement show that the silicalite-1 zeolite nanosheets with H-bonded silanols exhibit higher selectivity for caprolactam and longer reaction lifetime than those of the conventional silicalite-1 zeolite. Theoretical simulations reveal that the ammonium decomposed by urea is a critical additive for the formation of H-bond silanols. Obviously, one-pot synthesis of silicalite-1 zeolite nanosheets with rich H-bonded silanols plus excellent catalytic performance in the Beckmann rearrangement offer a new opportunity for development of highly efficient zeolites for catalytic applications in the future.

    Site requirements of supported W2C nanocatalysts for efficient hydrodeoxygenation of m-cresol to aromatics
    Yanling Yang, Peijie Han, Yuanbao Zhang, Jingdong Lin, Shaolong Wan, Yong Wang, Haichao Liu, Shuai Wang
    2024, 67:  91-101.  DOI: 10.1016/S1872-2067(24)60138-5
    Abstract ( 133 )   HTML ( 3 )   PDF (4302KB) ( 48 )  
    Supporting Information

    Selective hydrodeoxygenation of lignin derivatives into aromatic compounds is a promising route for the upgrading of lignin feedstocks. Metal carbide catalysts have exhibited excellent selectivity in hydrodeoxygenation reactions, while their structure-activity relationship is still in ambiguity. Herein, a liquid-phase atomic layer deposition method was employed to synthesize W2C/SiO2 catalysts with uniform and size-controllable W2C nanoparticles. For gas-phase hydrodeoxygenation of lignin-derived m-cresol at 350 °C, these W2C/SiO2 catalysts showed superior toluene selectivities (>95%) regardless of the W2C particle size. An optimal W2C particle size of ~7 nm was obtained for achieving the highest W2C-based hydrodeoxygenation rate. In contrast, the turnover rate per surface W site increased almost monotonously as the W2C particle size increased within 0.7‒15 nm, attributable to high-index planes appeared on the larger W2C nanoparticles. Kinetic effects of m-cresol and H2, taken together with temperature-programmed desorption of probe molecules and theoretical treatments, further indicate that the W2C surface is nearly saturated by adsorbed m-cresol or its derivates under the reaction condition and the H-addition of the C7H7* intermediate to form toluene, instead of the initial C-O cleavage in m-cresol, acts as the rate-determining step. A side-by-side comparison between W2C(102) and W2C(001) catalyst surfaces in theoretical simulations of m-cresol hydrodeoxygenation verifies that high-index planes can stabilize kinetically-relevant transition states more effectively than the low-index ones, as a result of more available less-coordinated active sites on the former. The above findings bring new mechanistic insights into the site requirements of supported W2C nanocatalysts, distinct from those metal-catalyzed hydrodeoxygenation of oxygenates.

    A chemoenzymatic cascade for sustainable production of chiral N-arylated aspartic acids from furfural and waste
    Guang-Hui Lu, Jian Yu, Ning Li
    2024, 67:  102-111.  DOI: 10.1016/S1872-2067(24)60146-4
    Abstract ( 823 )   HTML ( 5 )   PDF (2914KB) ( 233 )  
    Supporting Information

    Both biomass valorization and waste upcycling are important routes to sustain the circular bioeconomy. In this work, we present a chemoenzymatic cascade for selective synthesis of chiral N-arylated aspartic acids from biomass-derived furfural and waste nitrophenols (NPs) by merging robust photo- and electrocatalysis with stereoselective biocatalysis. Concurrent photoelectrocatalytic oxidation of furfural into maleic acid (MA) and fumaric acid (FA) was significantly enhanced by combining catalyst and reaction engineering strategies including identification of a powerful photocatalyst meso-tetra(4-carboxyphenyl)porphyrin, continuous flow technique, enhancing dissolved O2 and paired electrosynthesis. The overall space-time yield (STY) approached 2.8 g L-1 h-1 in a fed-batch process, with the product titer of 28.3 g L-1. Besides, photoelectrosynthesis of MA/FA was effectively fueled by sunlight, with the STY of up to 3.6 g L-1 h-1. Both MA selectivity and yield could be facilely improved to around 89% by reducing the buffer concentrations. Paired electrosynthesis strategy not only resulted in greatly improved MA production at the anode, but also enabled NPs upcycling into value-added aminophenols (APs) at the cathode. The products formed in the two electrode chambers were converted into N-arylated (S)-aspartic acids by a bienzymatic cascade. This work presents a multicatalytic approach for integrating selective biomass valorization and waste upcycling towards sustainable manufacture.

    Edge effect-enhanced CO2 adsorption and photo-reduction over g-C3N4 nanosheet
    Xuedong Jing, Xiaoyun Mi, Wei Lu, Na Lu, Shiwen Du, Guodong Wang, Zhenyi Zhang
    2024, 67:  112-123.  DOI: 10.1016/S1872-2067(24)60141-5
    Abstract ( 152 )   HTML ( 17 )   PDF (5470KB) ( 64 )  
    Supporting Information

    Effective CO2 adsorption and fast electron injection are two crucial processes of photocatalysts for achieving high-efficiency CO2 photo-reduction. However, simultaneously enhancing these processes within a single photocatalyst remains a challenging task. Herein, we propose an intriguing edge effect based on the intrinsic atomic structure of g-C3N4 nanosheets (NSs) to enhance their CO2 adsorption and facilitate the transfer of photo-generated electrons to the adsorbed CO2. By cutting large pieces of g-C3N4 NSs into smaller fragments, the exposure of amino groups at the edges of its repeating tri-s-triazine units can be significantly increased. These edge-exposed amino groups serve as active sites for enhancing the CO2 capture capacity of g-C3N4 NSs. As we decrease the lateral size of g-C3N4 NSs from tens of micrometers to hundreds of nanometers, their CO2 adsorption capacity increases from 4.74 to 8.56 cm3 g-1. Reducing the size of g-C3N4 NSs also facilitates the transfer of photo-generated electrons to the edge-adsorbed CO2. Thus, our optimized g-C3N4 NSs with the edge effect exhibits a 37-fold enhancement in activity for CO2 photo-reduction compared to normal g-C3N4 NSs under simulated sunlight irradiation. Notably, by introducing Pt cocatalysts, we can control product selectivity from 85.9% CO to 97.9% CH4.

    LSPR-assisted W18O49/ZnO S-scheme heterojunction for efficient photocatalytic CO2 N-formylation of aniline
    Jiafa Chen, Peng Bai, Shibo Yuan, Yi He, Zifan Niu, Yicheng Zhao, Yongdan Li
    2024, 67:  124-134.  DOI: 10.1016/S1872-2067(24)60149-X
    Abstract ( 183 )   HTML ( 19 )   PDF (20044KB) ( 69 )  
    Supporting Information

    Designing highly efficient photocatalyst for the valorization of CO2 is an ideal strategy to reduce greenhouse gas emissions and utilize solar energy. In this study, a S-scheme heterojunction photocatalyst is fabricated by solvothermal impregnation of ZnO on W18O49 for photocatalytic CO2 N-formylation of aniline. The localized surface plasmon resonance effect of W18O49 improves the absorption capacity for long-wave light significantly, and the hot electrons generated in W18O49 with a high energy can migrate to the conduction band of ZnO and thus enhance the photocatalytic reduction ability. Meanwhile, the S-scheme heterojunction facilitates the separation of photoinduced charge carriers and preserves the redox ability of W18O49/ZnO composite photocatalyst. The conversion of aniline reaches 99.1% after 5 h reaction under visible light irradiation at room temperature with an N-formylaniline selectivity of 100%. A possible photocatalytic reaction mechanism is proposed. This study paves a promising way for the design of highly efficient photocatalyst and the sustainable utilization of CO2.

    Role of extra-framework aluminum species within MOR zeolites for syngas conversion via OXZEO catalysis
    Haodi Wang, Feng Jiao, Jingyao Feng, Yuting Sun, Guangjin Hou, Xiulian Pan, Xinhe Bao
    2024, 67:  135-143.  DOI: 10.1016/S1872-2067(24)60135-X
    Abstract ( 146 )   HTML ( 9 )   PDF (1441KB) ( 47 )  
    Supporting Information

    The location of aluminum within the framework or extra-framework of zeolites is a critical factor in determining its catalytic performance. Despite extensive research on the identification and formation mechanism of extra-framework aluminum (EFAl), its impact on catalytic performance requires further investigation. Herein, mordenite (MOR) zeolites with comparable acid density within the 8MR and 12MR channels but different EFAl contents were prepared, and their catalytic roles were examined in syngas conversion. Intelligent gravimetric analysis, model experiment of ethylene conversion and thermogravimetric analysis demonstrate that the existence of EFAl species can inhibit the secondary conversion of ethylene to long chain hydrocarbons (i.e., C5+) as well as the over-accumulation of carbonaceous species. However, excessive EFAl species lead to rapid deactivation due to restricted space and thus severe diffusion limitation. MOR zeolite with a moderate amount of EFAl species achieves a superior ethylene selectivity and exhibits an enhanced stability in syngas conversion when combined with ZnAlOx oxide. The insights gained in this work provide important guidance for the design of more efficient zeolite-based catalysts.

    Dual-metal synergy unlocking ROS-free catalysis for rapid aerobic oxidation of 5-hydroxymethylfurfural at room temperature
    Meiyun Zhang, Penghua Che, Hong Ma, Xin Liu, Shujing Zhang, Yang Luo, Jie Xu
    2024, 67:  144-156.  DOI: 10.1016/S1872-2067(24)60151-8
    Abstract ( 165 )   HTML ( 2 )   PDF (3912KB) ( 50 )  
    Supporting Information

    Clean catalytic oxidation has a broad prospect in the modern chemical engineering and energy chemistry fields. However, unexpected over-oxidation and disruptive degradation are frequently induced by excessive reactive oxygen species (ROS). Herein, we reported a new ROS-free approach to effectively drive O2 to be activated into highly reactive surface peroxo species through enzyme-mimicking mechanism. Benefiting from the dual-metal synergy effect between Cu and Co active sites, ROS (H2O2 and OH) is generated in situ while further scavenged completely into surface peroxo species, which gives rise to very high selectivity and extremely high carbon balance. For example, the CuCo/N-C catalyst affords >99.8% conversion and 94.5% selectivity to 2,5-furanedicarboxylic acid at 25 °C for 6 h in the aerobic oxidation of biomass platform 5-hydroxymethylfurfural. Moreover, it achieved exceptional performance in the oxidation of a variety of hydroxyl compounds to organic acids with high yields (89.9%-99.5%) at a mild temperature (25-40 °C). This exploration introduces an innovative clue for emulating enzyme catalysts, thereby enriching our comprehension and advancement of biologically inspired catalytic oxidations.

    Artificial metalloenzymes enabled by combining proteins with hemin via protein refolding
    Jingping Ouyang, Zhenfang Zhang, René Hübner, Henrik Karring, Changzhu Wu
    2024, 67:  157-165.  DOI: 10.1016/S1872-2067(24)60150-6
    Abstract ( 115 )   HTML ( 3 )   PDF (2279KB) ( 37 )  
    Supporting Information

    In this study, we unveil a conceptual technology for fabricating artificial metalloenzymes (ArMs) by deeply integrating hemin into protein scaffolds via a protein refolding process, a method that transcends the conventional scope of surface-level modifications. Our approach involves denaturing proteins, such as benzaldehyde lyase, green fluorescent protein, and Candida antarctica lipase B, to expose extensive reactive amino acid residues, which are then intricately linked with hemin using orthogonal click reactions, followed by protein refolding. This process not only retains the proteins’ structural integrity but expands proteins’ functionality. The most notable outcome of this methodology is the hemin@BAL variant, which demonstrated a remarkable 83.7% conversion rate in cyclopropanation reactions, far surpassing the capabilities of traditional hemin-based catalysis in water. This success highlights the significant role of protein structure in the ArMs’ activity and marks a substantial leap forward in chemical modification of proteins. Our findings suggest vast potentials of protein refolding approaches for ArMs across various catalytic applications, paving the way for future advancements in synthetic biology and synthetic chemistry.

    Catalytic production of fused tetracyclic high-energy-density fuel with biomass-derived cyclopentanone and benzoquinone
    Xu Zhang, Wen-Jing Zhang, Yan-Cheng Hu, Zhi-Guang Zhang, Jing-Pei Cao
    2024, 67:  166-175.  DOI: 10.1016/S1872-2067(24)60148-8
    Abstract ( 148 )   HTML ( 2 )   PDF (1239KB) ( 44 )  
    Supporting Information

    High-energy-density (HED) fuels (e.g. JP-10) are of great importance in safeguarding territorial air security, since they can increase the flight range and payload of military aircrafts. To reduce the reliance on limited petroleum source, the production of HED fuel with renewable biomass feedstocks is highly appealing. But currently, most of the synthetic biofuels, due to their intrinsic ring structure, are incapable of competing with JP-10 in terms of energy density and freezing point. By emulating the structural characteristic of JP-10, we herein design and prepare a special C16 fused tetracyclic biofuel using renewable cyclopentanone and benzoquinone as feedstocks. Key to success depends on selective dehydration of vicinal diol (dimer of cyclopentanone) over Amberlyst-15 in [Hmim]Cl. The Amberlyst-15/[Hmim]Cl system effectively suppresses the dominant pinacol-type rearrangement pathway and also exhibits good reusability for the dehydration. The hydrogen-bonding interaction between vicinal diol and imidazolium ring, as well as electrostatic force between carbocation intermediate and chloride anion contribute to the high diene selectivity. The compact ring framework gives rise to a density of 0.966 g/mL, combustion heat of 43.1 MJ/L, freezing point of ‒67 °C, and kinematic viscosity of 12.4 cSt, which are comparable to the properties of JP-10. It is expected that this as-prepared HED biofuel may potentially serve as a renewable alternative to petroleum fuel JP-10.

    Mo-doping and CoOx loading over BiVO4 photoanode for enhancing performance of H2O2 synthesis and in-situ organic pollutant degradation
    Tian Tian, Wanting Wang, Yiping Wang, Kexin Li, Yuanyuan Li, Wensheng Fu, Yong Ding
    2024, 67:  176-185.  DOI: 10.1016/S1872-2067(24)60175-0
    Abstract ( 249 )   HTML ( 20 )   PDF (2290KB) ( 102 )  
    Supporting Information

    The combination of photoelectrochemical water oxidation hydrogen peroxide (H2O2) on the anode and hydrogen evolution on the cathode increase the value of the water splitting process. However, the sluggish water oxidation kinetics and slow carrier transport limit the generation of H2O2. In this study, to promote H2O2 production, the surface of a Mo doped BiVO4 photoanode was modified with CoOx co-catalyst. The resulting CoOx/Mo-BiVO4 photoanode generates H2O2 at a rate of 0.39 μmol min-1 cm-2 with a selectivity of 76.9% at 1.7 VRHE. The experimental results indicate that CoOx decorated on Mo-BiVO4 kinetically favors the H2O2 production via reduced band bending, while inhibiting H2O2 decomposition. According to density functional theory calculations, the loading of CoOx enhances the efficiency of the Mo-BiVO4 photoanode in generating H2O2. Moreover, the in-situ generated H2O2 through CoOx/Mo-BiVO4 was applied to the degradation of tetracycline in aqueous solution, finding that CoOx/Mo-BiVO4 exhibits the best performance among the catalysts evaluated. This work demonstrates that the CoOx co-catalyst can effectively facilitate the water oxidation to H2O2, opening a way for its application in situ water remediation.

    Cu-induced interface engineering of NiCu/Ni3N heterostructures for enhanced alkaline hydrogen oxidation reaction
    Jinchi Li, Wanhai Zhou, Shuqi Yu, Chen Qing, Jian He, Liang Zeng, Yao Wang, Yungui Chen
    2024, 67:  186-193.  DOI: 10.1016/S1872-2067(24)60142-7
    Abstract ( 167 )   HTML ( 5 )   PDF (2827KB) ( 40 )  
    Supporting Information

    Constructing well-defined interfaces in catalysts is a highly effective method to accelerate reactions with multiple intermediates. In this study, we developed a heterostructure catalyst combining fcc NiCu and hcp Ni3N, aiming at achieving superior performance in alkaline hydrogen electrocatalysis. The NiCu/Ni3N not only overcomes the inadequate hydroxyl binding energy performance of NiCu alloys but also solves the problems of insufficient active sites found in most Ni/Ni3N. Experimental results and density functional theoretical calculations reveal that the formation of heterostructure significantly depends on the amount of Cu. This approach effectively prevents the side effects of increased catalyst particle size, typically resulting from the high temperatures and prolonged reaction times required for conventional synthesis of Ni/Ni3N. The interface of this heterostructure induces a distinctive overlapping effect that enhances the adsorption of water and lowers the energy barrier for the rate-determining step. The NiCu/Ni3N catalyst shows an impressive activity of 71.8 mA mg-1 at an overpotential of 50 mV, a 14.7 times efficiency enhancement compared to pure Ni and comparable to that of low-loaded commercial Pt/C. This research highlights the potential of NiCu/Ni3N in advancing catalyst development.

    4 d Metal-doped liquid Ga for efficient ammonia electrosynthesis at wide N2 concentrations
    Yingying Wei, Yuyao Sun, Yaodong Yu, Yue Shi, Zhe Wu, Lei Wang, Jianping Lai
    2024, 67:  194-203.  DOI: 10.1016/S1872-2067(24)60144-0
    Abstract ( 128 )   HTML ( 4 )   PDF (7746KB) ( 37 )  
    Supporting Information

    Electrocatalytic nitrogen reduction reaction under ambient conditions is a promising pathway for ammonia synthesis. Currently nitrogen reduction reactions are carried out in N2-saturated environments and use high-purity nitrogen as feedstock, which is costly. Here, we prepared carbon-coated ultra-low 4d metal Ru-doped liquid metal Ga (Ru0.06/LM@C) for NRR over a wide range of N2 concentrations. Comprehensive analyses show that the introduction of the ultra-low 4d element Ru can effectively adjust the electronic structure through orbital interactions, thus enhancing the adsorption of nitrogen-containing intermediates. The liquid catalyst utilized its mobility to provide a higher density of active sites. In addition, the material Ru0.06/Ga@C itself has the ability to promote product desorption. The three act synergistically to optimize the N2 mass transfer path, thereby increasing the *NNH coverage and further improving the ammonia yield over a wide range of N2 concentrations. The maximum NH3 yield of the catalyst can reach 126.0 μg h-1 mgcat-1 (at -0.3 V vs. RHE) with high purity N2 as feed gas, and the Faraday efficiency is 60.4% at -0.1 V vs. RHE. Over a wide range of N2 concentrations, the NH3 yield of the catalyst was greater than 100 μg h-1 mgcat-1 with a Faraday efficiency higher than 47%. The catalytic performance is much higher than that of solid Ga@C and reported p-block metal-based catalysts.