Characterization of CoMn catalyst by in situ X-ray absorption spectroscopy and wavelet analysis for Fischer–Tropsch to olefins reaction

Cobalt carbide has recently been reported to catalyse the FTO con version of syngas with high selectivity for the production of lower olefins (C2-C4). Clarifying the formation process and atomic structure of cobalt carbide will help understand the catalytic mechanism of FTO. Herein, hydrogenati on of carb on monoxide was investigated for cobalt carbide synthesized from CoMn catalyst, followed by X-ray diffraction, transmission electron microscopy, temperature programmed reaction and in situ X-ray absorption spectroscopy. By monitoring the evolution of cobalt carbide during syngas conversion, the wavelet transform results give evidenee for the formation of the cobalt carbide and clearly demonstrate that the active site of catalysis was cobalt carbide.

Effects of cobalt carbide on Fischer–Tropsch synthesis with MnO supported Co-based catalysts

Cobalt carbide(Co2C)was considered as potential catalysts available for large-scale industrialization of transforming syngas(H2 and CO)to clean fuels.Herein,we successfully synthesized Co-based catalysts with MnO supported,to comprehend the effects of Co2C for Fischer–Tropsch synthesis(FTS)under ambient conditions.The huge variety of product selectivity which was contained by different active sites(Co and Co2C)has been found.Furthermore,density functional theory(DFT)shows that Co2C is efficacious of CO adsorption,whereas is weaker for H adsorption than Co.Combining the advantages of Co and Co2C,the catalyst herein can not only obtain more C5+products but also suppress methane selectivity.It can be a commendable guide for the design of industrial application products in FTS.

Atomic-level correlation between the electrochemical performance of an oxygen-evolving catalyst and the effects of CeO_(2) functionalization

Herein,we prepared a bimetallic layered double hydroxide(FeCo LDH)featuring a dandelion-like structure.Anchoring of CeO_(2)onto FeCo LDH produced interfaces between the functionalizing CeO_(2)and the parent LDH.Comparative electrochemical studies were carried out.Onset potential,overpotential,and Tafel slope point to the superior oxygen-evolving performance of CeO_(2)-FeCo LDH with respect to FeCo LDH,therefore,demonstrating the merits of CeO_(2)functionalization.The electronic structures of Fe,Co,and Ce were analyzed by X-ray photoelectron spectroscopy(XPS)and electron energy loss spectroscopy(EELS)from which the increase of Co^(3+)and the concurrent lowering of Ce^(4+)were established.With the use of CeO_(2)-FeCo LDH,accelerated formation at a sizably reduced potential of Co-OOH,one of the key intermediates preceding the release of O_(2)was observed by in situ Raman spectroscopy.We now have the atomic-level and location-specific evidence,the increase of the active Co^(3+)across the interface to correlate the enhanced catalytic performance with CeO_(2)functionalization.

Uniform small metal nanoparticles anchored on CeO2 nanorods driven by electroless chemical deposition

We report a facile electroless chemical deposition(ECD)method to deposit uniform Pd nanoparticles((2.5±0.6)nm)on CeO2 nanorods(PdNPs/CeO2-ECD)through the interface redox reaction between the reduced CeO2 and Na2PdCl4.Pd NPs/CeO2-ECD exhibits a stronger electronic metal-support interaction(EMSI)evidenced by higher reducibility and stronger anti-sintering capability at high temperatures,compared to that prepared by the conventional impregnation method.Such an EMSI effect of PdNPs/CeO2-ECD significantly improves its catalytic activity in CO oxidation.Besides,the chlorine residue-free catalysts through ECD process avoid the deleterious effect of chlorine on CO oxidation.This ECD process can further be extended to deposit various uniform nanoscaled noble metals(Au,Ag,Pt,Ru,Rh,etc.)on CeO2,which may deliver their potentials in advanced catalysis.

Quaternary pyrite-structured nickel/cobalt phosphosulfide nanowires on carbon cloth as efficient and robust electrodes for water electrolysis

元素替换的策略是在催化剂调节活跃地点的电子结构的一个有效方法，从而在催化活动和稳定性导致改进。此处，我们设计并且综合黄铁矿类型镍 / 磷共同做碳布(NiCoPS/CC ) 上的公司 2 nanowires 为水电解的同样有效、持久的电极。镍和磷的介绍由于催化剂的活跃地点的电子结构的规定在氢进化反应生产了电极的表演的逐步、出色的改进并且在一个宽 pH 范围(014 ) 上加速了费用转移。也交付的 NiCoPS/CC 电极一将近 undecayed 10

Protection strategy for improved catalytic stability of silicon photoanodes for water oxidation

Silicon-based electrodes have attracted great attention in the artificial photosynthetic systems that mimic natural photosynthesis and directly convert the solar energy into chemical energy. Despite significant efforts to date,catalytic stability of the silicon photoelectrodes is limited by their poor electrochemical stability. The formation of passivation or protective layers provides a feasible strategy to improve the photocatalytic stability of silicon photoelectrodes. Many candidates including metals, metal oxides, metal silicides and polymers have been explored as the protection layers for silicon photoelectrodes. The present review gives a concise overview of the protected silicon photoanodes for water oxidation with a focus on the relationship between the structural architecture of silicon photoanodes and their photocatalytic activity and stability.

Influence of the Metal Ions on the Allylic Rearrangement Reac- tion of 3,4,5,6-Tetrahydrophthalic Anhydride

To further investigate the influence of metal ions on the allylic rearrangement of 3,4,5,6-tetrahydrophthalic an- hydride during the hydrothermal reaction, metal ions such as manganese（Ⅱ）, zinc（Ⅱ） and cadmium（Ⅱ） have been employed in the synthesis, which leads to the formation of three new lamellar coordination polymers, [MnⅡs（μ3-OH）3（1-chec）（1,2-chedc）（2,3-chedc）2（H20）] （3Mn）, [ZnⅡs（μ3-OH）3（1-chec）（1,2-chedc）（2,3-chedc）2（H20）] （4Zn）, and [CdⅡ3（μ3-OH）2（1,2-chedc）2] （5Cd） （1-chec=cyclohexene-l-carboxylate, 1,2-chedc=cyclohexene-1,2- dicarboxylate, 2,3-chedc=cyclohexene-1,2-dicarboxylate）. Interestingly, the allylic rearrangement reaction is metal-dependent, which occurs only in 3Mn and 4Zn, resulting in the formation of one chiral carbon atom of the corresponding dicarboxylate ligands in both compounds. In addition, the magnetic property of compound 3Mn was studied, which revealed strong antiferromagnetic interactions between the metal centers.