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Chinese Journal of Catalysis
2018, Vol. 39, No. 2
Online: 18 February 2018


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Li and coworkers in their Article on pages 250–257 reported the selective hydrogenation of carboxylic acids to corresponding alcohols using earth-abundant cobalt oxides through a reaction-controlled catalysis process, namely the further reaction of alcohols completely hindered by the presence of carboxylic acids. The partial reduction of cobalt oxides to cobalt monoxide can dramatically enhance the catalytic activity for the selective hydrogenation of carboxylic acids.

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Table of Contents for VOL.39 No.2 2018, 39 (2):  0-0.  Abstract ( 172 )   PDF (1248KB) ( 627 )

Reviews

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Metal-organic frameworks for highly efficient oxygen electrocatalysis Xiaobo He, Fengxiang Yin, Hao Wang, Biaohua Chen, Guoru Li 2018, 39 (2):  207-227.  DOI: 10.1016/S1872-2067(18)63017-7 Abstract ( 692 )   [Full Text(HTML)] () PDF (1391KB) ( 2018 )   Metal-organic frameworks (MOFs) are a series of highly porous crystalline materials, which are built from inorganic metal nodes and organic linkers through coordination bonds. Their unique porous structural features (such as high porosity, high surface areas, and highly ordered nanoporous structures) and designable structures and compositions have facilitated their use in gas capture, separation, catalysis, and energy storage and conversion. Recently, the design and synthesis of pure MOFs and their derivatives have opened new routes to develop highly efficient electrocatalysts toward oxygen reduction reactions (ORR) and oxygen evolution reactions (OER), which are the core electrode reactions in many energy storage and conversion techniques, such as metal-air batteries and fuel cells. This review first discusses recent progress in the synthesis and the electrocatalytic applications of pure MOF-based electrocatalysts toward ORR or OER, including pure MOFs, MOFs decorated with active species, and MOFs incorporated with conductive materials. The following section focuses on the advancements of the design and preparation of various MOF-derived materials-such as inorganic nano-(or micro-) structures/porous carbon composites, pure porous carbons, pure inorganic nano-(or micro-) structured materials, and single-atom electrocatalysts-and their applications in oxygen electrocatalysis. Finally, we present a conclusion and an outlook for some general design strategies and future research directions of MOF-based oxygen electrocatalysts.

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Mononuclear first-row transition-metal complexes as molecular catalysts for water oxidation Ni Wang, Haoquan Zheng, Wei Zhang, Rui Cao 2018, 39 (2):  228-244.  DOI: 10.1016/S1872-2067(17)63001-8 Abstract ( 459 )   [Full Text(HTML)] () PDF (1410KB) ( 1266 )   Water oxidation is significant in both natural and artificial photosynthesis. In nature, water oxidation occurs at the oxygen-evolving center of photosystem Ⅱ, and leads to the generation of oxygen, protons, and electrons. The last two are used for fixation of carbon dioxide to give carbohydrates. In artificial processes, the coupling of water oxidation to evolve O2 and water reduction to evolve H2 is known as water splitting, which is an attractive method for solar energy conversion and storage. Because water oxidation is a thermodynamically uphill reaction and is kinetically slow, this reaction causes a bottleneck in large-scale water splitting. As a consequence, the development of new and efficient water oxidation catalysts (WOCs) has attracted extensive attention. Recent efforts have identified a variety of mononuclear earth-abundant transition-metal complexes as active and stable molecular WOCs. This review article summarizes recent progress in research on mononuclear catalysts that are based on first-row transition-metal elements, namely manganese, iron, cobalt, nickel, and copper. Particular attention is paid to catalytic mechanisms and the key O-O bond formation steps. This information is critical for designing new catalysts that are highly efficient and stable.

Communication

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Chemical fixation of carbon dioxide to cyclic carbonates catalyzed by zinc(Ⅱ) complex bearing 1,2-disubstituted benzimidazole ligand Jorge L. S. Milani, Igor S. Oliveira, Pamella A. Dos Santos, Ana K. S. M. Valdo, Felipe T. Martins, Danielle Cangussu, Rafael P. Das Chagas 2018, 39 (2):  245-249.  DOI: 10.1016/S1872-2067(17)62992-9 Abstract ( 352 )   [Full Text(HTML)] () PDF (385KB) ( 1046 )   A new zinc(Ⅱ) complex of formula[ZnCl2(L1)2] (1)[L1=2-(2-thienyl)-1-(2-thienylmethyl)-1H-benzimidazole] was synthesized and fully characterized by nuclear magnetic resonance and infrared spectroscopy, elemental analysis, electrospray ionization high-resolution mass spectrometry, and thermogravimetric analysis. The molecular structure was confirmed by single-crystal X-ray diffraction. Complex 1 consists of mononuclear tetrahedral zinc(Ⅱ) units with a locked geometry resulting from weak intramolecular S…π and π-π interligand interactions. The benzimidazole ligand and its zinc(Ⅱ) complex were readily obtained through a simple synthetic route. The catalytic activity of 1 was investigated in the coupling of carbon dioxide with epoxides to produce cyclic carbonates, and a series of parameters were evaluated. The complex efficiently catalyzed the transformation of various epoxides under solvent-free conditions, with good conversions, turnover numbers, and turnover frequencies.

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Robust cobalt oxide catalysts for controllable hydrogenation of carboxylic acids to alcohols Song Song, Dong Wang, Lu Di, Chuanming Wang, Weili Dai, Guangjun Wu, Naijia Guan, Landong Li 2018, 39 (2):  250-257.  DOI: 10.1016/S1872-2067(17)63003-1 Abstract ( 573 )   [Full Text(HTML)] () PDF (1037KB) ( 1396 )   The selective catalytic hydrogenation of carboxylic acids is an important process for alcohol production, while efficient heterogeneous catalyst systems are still being explored. Here, we report the selective hydrogenation of carboxylic acids using earth-abundant cobalt oxides through a reaction-controlled catalysis process. The further reaction of the alcohols is completely hindered by the presence of carboxylic acids in the reaction system. The partial reduction of cobalt oxides by hydrogen at designated temperatures can dramatically enhance the catalytic activity of pristine samples. A wide range of carboxylic acids with a variety of functional groups can be converted to the corresponding alcohols at a yield level applicable to large-scale production. Cobalt monoxide was established as the preferred active phase for the selective hydrogenation of carboxylic acids.

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Effect of χ-alumina addition on H2S oxidation properties of pure and modified γ-alumina Svetlana A. Yashnik, Vadim V. Kuznetsov, Zinfer R. Ismagilov 2018, 39 (2):  258-274.  DOI: 10.1016/S1872-2067(18)63016-5 Abstract ( 412 )   [Full Text(HTML)] () PDF (1138KB) ( 889 )   The influence of the textural and acidic properties of γ-Al2O3, (γ+χ)-Al2O3, and α-Al2O3 on the catalytic activity, selectivity, and stability of direct H2S oxidation has been studied. A comparison of the H2S-to-S conversion effectiveness of aluminas with their acidic properties (identified by Fourier transform infrared spectroscopy and temperature programmed desorption of NH3) shows that H2S adsorption occurs predominantly on weak Lewis acid sites (LAS). γ-Alumina samples containing a χ-phase and/or modified Mg2+ ions have a greater concentration of weak LAS and exhibit greater catalytic activity. When alumina is treated with a sulfuric acid solution, strong LAS appear and the number of LAS decreases significantly. Modification of alumina with hydrochloric acid has a limited effect on LAS strength. Weak LAS are retained and double in number compared to that present in the unmodified alumina, but the treated sample has Al-Cl bonds. Alumina samples modified by sulfate and chloride anions exhibit poor catalytic activity in H2S oxidation.

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Hydrothermal synthesis and catalytic performance of bulky titanium silicalite-1 aggregates assembled by bridged organosilane Li Chen, Teng Xue, Jian Ding, Hai Hong Wu, Kun Zhang, Peng Wu, Ming, Yuan He 2018, 39 (2):  275-282.  DOI: 10.1016/S1872-2067(18)63026-8 Abstract ( 382 )   [Full Text(HTML)] () PDF (2461KB) ( 1245 )   A facile and effective method to synthesize TS-1 zeolite aggregates has been presented. The crystallization of silanized seeds and nanocrystallites led to large and irregular TS-1 zeolite aggregates ranging from 5 to 40 μm in size, based on the special sol-gel chemistry of bridged organosilane. Epoxidation of 1-hexene and cyclohexene was used as a probe reaction to investigate the catalytic performance of the resulting materials. These TS-1 zeolite aggregates possessed both the conventional nanoparticle properties of TS-1 zeolites and variable surface hydrophilic/hydrophobic features, which enhanced the catalytic properties of hydroperoxides for alkene epoxidation. Moreover, the large aggregates effectively simplified the separation procedure during preparation and catalytic reactions.

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Encapsulation of a nickel Salen complex in nanozeolite LTA as a carbon paste electrode modifier for electrocatalytic oxidation of hydrazine Seyed Karim Hassaninejad-Darzi 2018, 39 (2):  283-296.  DOI: 10.1016/S1872-2067(18)63025-6 Abstract ( 381 )   [Full Text(HTML)] () PDF (1117KB) ( 1020 )   Supporting Information A nickel salen complex was encapsulated in the supercages of nanozeolite NaA, LTA (linde type A) structure, using the flexible ligand method. The electrochemical behavior and electrocatalytic activity of a carbon paste electrode (CPE) modified with Ni(Ⅱ)-Salen-A (Ni(Ⅱ)-SalenA/CPE) for hydrazine oxidation in 0.1 mol/L NaOH solution were investigated by cyclic voltammetry, chronoamperometry, and chronocoulometry. First, organic-template-free synthesis of nanozeolite LTA was performed and the obtained material was characterized by various techniques. The average particle size of the LTA crystals was estimated to be 56.1 and 72 nm by X-ray diffraction and particle size analysis, respectively. The electron transfer coefficient was found to be 0.64 and the catalytic rate constant for oxidation of hydrazine at the redox sites of Ni(Ⅱ)-SalenA/CPE was found to be 1.03×105 cm3/(mol·s). Investigation of the electrocatalytic mechanism suggested that oxidation of hydrazine occurred through reaction with Ni3+(Salen)O(OH) and also direct electrooxidation. The anodic peak currents revealed a linear dependence on the square root of the scan rate, indicating a diffusion-controlled process, and the diffusion coefficient of hydrazine was found to be 1.18×10-7 cm2/s. The results indicated that Ni(Ⅱ)-SalenA/CPE displays good electrocatalytic activity toward hydrazine oxidation owing to the porous structure of nanozeolite LTA and the Ni(Ⅱ)-Salen complex. Finally, the general reaction mechanism for the electrooxidation of hydrazine on Ni(Ⅱ)-SalenA/CPE in alkaline solution involves the transfer of four electrons, in which the first electron transfer reaction acts as the rate-limiting step followed by a three-electron process to generate environmentally friendly nitrogen and water as final products.

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ZrO2-modified Ni/LaAl11O18 catalyst for CO methanation:Effects of catalyst structure on catalytic performance Hongmei Ai, Hongyuan Yang, Qing Liu, Guoming Zhao, Jing Yang, Fangna Gu 2018, 39 (2):  297-308.  DOI: 10.1016/S1872-2067(17)62995-4 Abstract ( 376 )   [Full Text(HTML)] () PDF (1901KB) ( 1128 )   We report Ni/LaHA@ZrO2 catalysts prepared by a facile modified successive adsorption and reaction method for CO methanation. N2 adsorption, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, H2 temperature-programmed reduction, H2 temperature-programmed desorption, X-ray photoelectron spectroscopy, thermogravimetric analysis, and inductively coupled plasma atomic emission spectrometry were used to characterize the samples. The results indicated that the ZrO2 nanoparticles were distributed over the surface of the Ni/LaHA@ZrO2 catalyst and even partially covered some Ni particles, resulting in the coating exerting a confinement effect. The excess ZrO2 had an adverse effect on the enhancement of CO conversion because of the coverage of the surface Ni particles; however, the Ni/LaHA@ZrO2 catalyst displayed much higher CH4 selectivity than Ni/LaHA because of the activation of the byproduct CO2 molecules by ZrO2 species. Therefore, even though 20Ni/LaHA@ZrO2-5 exhibited similar CO conversion as 20Ni/LaHA, the use of the former resulted in a higher CH4 yield than the use of the latter. A 107-h-lifetime test revealed that the Ni/LaHA@ZrO2 catalyst was highly stable with superior anti-sintering and anti-coking properties because of its coating structure and the promoter effect of ZrO2.

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Oxidative coupling of alcohols and amines to an imine over Mg-Al acid-base bifunctional oxide catalysts Jinling Song, Guiyang Yu, Xi Li, Xuwei Yang, Wenxiang Zhang, Wenfu Yan, Gang Liu 2018, 39 (2):  309-318.  DOI: 10.1016/S1872-2067(17)63006-7 Abstract ( 380 )   [Full Text(HTML)] () PDF (1511KB) ( 1069 )   A series of Mg-Al mixed oxide catalysts are prepared and introduced as efficient irreducible catalysts for the oxidative coupling of alcohols and amines to imine. The structure and surface properties of Mg-Al oxides are modulated by changing the Mg/Al ratios, calcination temperature and treatment with probe molecules. Detailed characterization, including X-ray diffraction, 27Al magic angle spinning nuclear magnetic resonance spectroscopy, N2-adsorption, NH3-temperature-programmed desorption, CO2-temperature-programmed desorption and X-ray photoelectron spectroscopy are carried out to determine the physicochemical properties of these catalysts. The Mg-Al oxides with Mg/Al=3 exhibit the highest activity in the reaction, which possess a large number of surface weak basic sites and a relatively small number of weak acidic sites. The role of the acidic and basic sites in the reaction process is systematically investigated, and are shown to serve as adsorption and activation sites for amines and alcohols, respectively. Under the synergistic effect of these acid-base centers, the oxidative coupling process successfully occurs on the surface of Mg-Al mixed oxides. Compared with the acidic sites, the weak basic sites play a more important role in the catalytic process. The acidic sites are the catalytic centers for the benzyl alcohol activation, which control the reaction rate of the oxidative coupling reaction.

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Highly selective hydrogenation of furfural to tetrahydrofurfuryl alcohol over MIL-101(Cr)-NH2 supported Pd catalyst at low temperature Dongdong Yin, Hangxing Ren, Chuang Li, Jinxuan Liu, Changhai Liang 2018, 39 (2):  319-326.  DOI: 10.1016/S1872-2067(18)63009-8 Abstract ( 684 )   [Full Text(HTML)] () PDF (600KB) ( 1856 )   Supporting Information An efficient heterogeneous catalyst, Pd@MIL-101(Cr)-NH2, is prepared through a direct pathway of anionic exchange followed by hydrogen reduction with amino-containing MIL-101 as the host matrix. The composite is thermally stable up to 350℃ and the Pd nanoparticles uniformly disperse on the matal organic framework (MOF) support, which are attributed to the presence of the amino groups in the frameworks of MIL-101(Cr)-NH2. The selective hydrogenation of biomass-based furfural to tetrahydrofurfuryl alcohol is investigated by using this multifunctional catalyst Pd@MIL-101(Cr)-NH2 in water media. A complete hydrogenation of furfural is achieved at a low temperature of 40℃ with the selectivity of tetrahydrofurfuryl alcohol close to 100%. The amine-functionalized MOF improves the hydrogen bonding interactions between the intermediate furfuryl alcohol and the support, which is conducive for the further hydrogenation of furfuryl alcohol to tetrahydrofurfuryl alcohol in good coor-dination with the metal sites.

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Ruthenium(Ⅱ) complex catalysts bearing a 2,6-bis(tetrazolyl)pyridine ligand for the transfer hydrogenation of ketones Liandi Wang, Tingting Liu 2018, 39 (2):  327-333.  DOI: 10.1016/S1872-2067(17)62994-2 Abstract ( 384 )   [Full Text(HTML)] () PDF (521KB) ( 903 )   Three ruthenium(Ⅱ) complex catalysts bearing 2,6-bis(tetrazolyl)pyridine were synthesized, structurally characterized, and applied in the transfer hydrogenation of ketones. Their different catalytic activities were attributed to the different phosphine ligands on the 4-chloro-2,6-bis(1-(p-tolyl)-1H-tetrazol-5-yl)pyridine ruthenium(Ⅱ) complexes, with that based on 1,4-bis(diphenylphosphino) butane exhibiting better catalytic activity. A variety of ketones were reduced to their corresponding alcohols with >95% conversion.

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Mesoporous polyoxometalate-based ionic hybrid as a highly effective heterogeneous catalyst for direct hydroxylation of benzene to phenol Pingping Zha, Yunyun Zhan, Daokuan L, Hongyou Cu, Lipeng Zhan 2018, 39 (2):  334-341.  DOI: 10.1016/S1872-2067(17)62991-7 Abstract ( 414 )   [Full Text(HTML)] () PDF (701KB) ( 1039 )   Self-assembled mesoporous polyoxometalate-based ionic hybrid catalyst,[PxyDim]2.5PMoV2, was prepared by combining p-xylene-tethered diimidazole ionic liquid[PxyDim]Cl2 with Keg-gin-structured V-substituted polyoxometalate H5PMo10V2O40. The obtained hybrid was shown to be a mesostructured and hydrophobic material with good thermal stability. In the H2O2-based hydroxylation of benzene to phenol, the hybrid showed extraordinary catalytic activity and rate, and quite stable reusability. The unique hydrophobic properties and mesoporous structure of the hybrid were responsible for its excellent catalytic performance.

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Composition-controlled synthesis of platinum and palladium nanoalloys as highly active electrocatalysts for methanol oxidation Haiqiang Zhao, Weihong Qi, Xinfeng Zhou, Haofei Wu, Yejun Li 2018, 39 (2):  342-349.  DOI: 10.1016/S1872-2067(18)63020-7 Abstract ( 494 )   [Full Text(HTML)] () PDF (600KB) ( 1039 )   Supporting Information Platinum and palladium (PtPd) alloy nanoparticles (NPs) are excellent catalysts for direct methanol fuel cells. In this study, we developed PtPd alloy NPs through the co-reduction of K2PtCl4 and Na2PdCl4 in a polyol synthesis environment. During the reaction, the feed molar ratio of the two precursors was carried over to the final products, which have a narrow size distribution with a mean size of approximately 4 nm. The catalytic activity for methanol oxidation reactions possible depends closely on the composition of as-prepared PtPd alloy NPs, and the NPs with a Pt atomic percentage of approximately 75% result in higher activity and stability with a mass specific activity that is 7 times greater than that of commercial Pt/C catalysts. The results indicate that through composition control, PtPd alloy NPs can improve the effectiveness of catalytic performance.