阳离子交换树脂的有机催化进展

综述了聚苯乙烯型磺酸树脂、全氟磺酸树脂Nafion及崭新的Nafion/SiO2

Iron-based binary metal-organic framework nanorods as an efficient catalyst for the oxygen evolution reaction

First-row transition metal compounds have been widely explored as oxygen evolution reaction(OER)electrocatalysts due to their impressive performance in this application.However,the activity trends of these electrocatalysts remain elusive due to the effect of inevitable iron impurities in alkaline electrolytes on the OER;the inhomogeneous structure of iron-based(oxy)hydroxides further complicates this situation.Bimetallic metal-organic frameworks(MOFs)have the advantages of well-defined and uniform atomic structures and the tunable coordination environments,allowing the structure-activity relationships of bimetallic sites to be precisely explored.Therefore,we prepared a series of iron-based bimetallic MOFs(denoted as Fe_(2)M-MIL-88B,M=Mn,Co,or Ni)and systematically compared their electrocatalytic performance in the OER in this work.All the bimetallic MOFs exhibited higher OER activity than their monometallic iron-based counterpart,with their activity following the order FeNi>FeCo>FeMn.In an alkaline electrolyte,Fe2Ni-MIL-88B showed the lowest overpotential to achieve a current density of 10 mA cm^(–2)(307 mV)and the smallest Tafel slope(38 mV dec^(–1)).The experimental and calculated results demonstrated that iron and nickel exhibited the strongest coupling effect in the series,leading to modification of the electronic structure,which is crucial for tuning the electrocatalytic activity.

Improving the performance of metal-organic frameworks for thermo-catalytic CO_(2)conversion:Strategies and perspectives

Climate change caused by the increasing emission of CO_(2)to the atmosphere has become a global concern.To ameliorate this issue,converting CO_(2)into valuable chemicals is highly desirable,enabling a sustainable low-carbon future.To this end,developing efficient catalytic systems for CO_(2)conversion has sparked intense interests from both academia and industry.Taking advantage of their highly porous structures and unique properties,metal−organic frameworks(MOFs)have shown great potential as heterogeneous catalysts for CO_(2)conversion.Various transformations involving CO_(2)have been accomplished over MOFs-based materials.Here we provide a comprehensive and up-to-date review on recent advances of heterogeneous CO_(2)thermocatalysis using MOFs,highlighting relationships between structures and properties.Special attention is given to the design strategies for improving the catalytic performance of MOFs.Avenues available to enrich the catalytic active sites in MOF structures are stressed and their respective impacts on CO_(2)conversion efficiency are presented.The synergistic effects between each active site within the structure of MOFs and derivatives are discussed.In the end,future perspectives and challenges in CO_(2)conversion by heterogeneous catalysis with MOFs are described.

A vicinal effect for promoting catalysis of Pd1/TiO2:supports of atomically dispersed catalysts play more roles than simply serving as ligands

Atomically dispersing metal atoms on supports has been emerging as an effective strategy to maximize the atom utilization of metals for catalysis. However, due to the lack of effective tools to characterize the detailed structure of metal-support interface, the chemical functions of supports in atomically dispersed metal catalysts are hardly elucidated at the molecular level. In this work, an atomically dispersed Pdl/ Ti02 catalyst with Ti（III） vicinal to Pd is prepared and used to demonstrate the direct involvement of metal atoms on support in the catalysis of dispersed metal atoms. Systematic studies reveal that the Ti （IlI）-O-Pd interface facilitates the activation of 02 into superoxide （02）, thus promoting the catalytic oxi- dation. The catalyst exhibits the highest CO turn-over frequency among ever-reported Pd-based catalysts, and enhanced catalysis in the combustion of harmful volatile organic compound （i.e., toluene） and green- house gas （i.e., methane）. The demonstrated direct involvement of metal atoms on oxide support suggests that the real active sites of atomically dispersed metal catalysts can be far beyond isolated metal atoms themselves. Metal atoms on oxide supports in the vicinity serve as another vector to promote the catalysis of atomically dispersed metal catalysts.

Organocatalytic asymmetric allylic alkylation of sulfonylimidates with Morita-Baylis-Hillman carbonates

The asymmetric allylic alkylation reaction of sulfonylimidates with various Morita-Baylis-Hillman (MBH) carbonates was accomplished by the catalysis of commercially available cinchona alkaloids catalyst (DHQD)2AQN.The corresponding allylic alkylation products were obtained in good yields with high stereoselectivities (up to 99% ee,89:11 dr).