摘要：单原子位点催化剂(SSCs)由于能够产生丰富的活性物质来清除类芬顿体系中的污染物,而显示出广阔的潜力.然而,在高级氧化工艺中,实现金属原子100%的利用率和减少金属浸出以满足环境安全标准是困难的.在此基础上,利用强极化力获得了Co原子含量极低(~0.17%)的催化剂,提高了金属原子利用率,降低了抗生素消除过程中金属浸出的风险.正如预期,该催化剂具有有限的Co位点,伴随着丰富的缺陷和大量从大孔到中孔再到微孔分布的骨架,实现了快速的四环素降解(0.07133 min^(−1))和优异的归一化速率常数(k per-site,2.4726×10^(5) min^(−1) M^(−1)).实验和理论结果均表明,充分暴露具有丰富C-N缺陷的Co位点,可以提高Co活性位点的电子密度,降低过硫酸盐(PDS)的吸附能,从而优化Co原子对PDS活化的利用.该研究为设计高性能、环境友好的水修复用SSCs提供了有价值的见解.

摘要：将不同金属元素通过合金化形成二维材料(金属烯)对基础研究和纳米电子器件的实际应用具有重要意义,但目前鲜有金属烯材料是具有本征带隙的半导体.受离子晶体成键特征的启发,通过结构搜索、成键分析和高通量第一性原理计算,本文从2500多个双金属烯中筛选出一系列具有晶格动力学稳定和碱金属-金离子键的二维碱金属金化物双金属烯半导体.由于碱金属和金之间的大电负性差,其中32个碱金属金化物双金属烯是带隙范围为0.97~5.20 eV的半导体材料,而锂金双金属烯由于电负性差减小呈现出金属性.Bohn-Oppenheimer分子动力学模拟表明19个双金属烯在室温下结构稳定有利于实际应用.这项研究为设计双金属烯半导体提供了指导,并揭示了二维金属合金中成键行为和电子结构性质间的关联.

摘要：铂(Pt)是质子交换膜燃料电池(PEMFCs)阳极氢氧化反应(HOR)中最先进的电催化剂.然而,Pt催化剂对CO(工业低成本氢燃料中的杂质)极度敏感从而中毒,这会引起器件性能的急剧衰退,导致器件运行成本高.因此,提高Pt催化剂的CO耐受性对PEMFCs的商业化推广至关重要.在此,我们设计合成了一种独特的PtNiW@WO_(x)核壳纳米线来提高Pt基催化剂对CO的耐受能力.机理研究表明,表面无定形的WO_(x)壳层可以作为分子围栏,在动力学上阻碍CO扩散到达Pt位点.在热力学上,Ni和W元素合金化产生的电子效应可以使Pt的d带中心降低,减弱CO在Pt位点上的化学吸附.此外,亲氧W元素可以加速水的解离,提供更多OH活性物种,促进CO的氧化脱附.因此,在1000ppm CO/H_(2)条件下,所设计的PtNiW@WO_(x)核壳纳米线催化剂表现出优异的HOR抗CO中毒性能,在4000 s后仍能保持超过90%的HOR电流密度,超过了原始的PtNi纳米线和目前报道的绝大多数Pt基催化剂.

摘要：The energy crisis and global warming become severe issues. Solar-driven CO2 reduction provides a promising route to confront the predicaments, which has received much attention. The photoelectrochemical（PEC） process,which can integrate the merits of both photocatalysis and electrocatalysis, boosts splendid talent for CO2 reduction with high efficiency and excellent selectivity. Recent several decades have witnessed the overwhelming development of PEC CO2 reduction. In this review, we attempt to systematically summarize the recent advanced design for PEC CO2 reduction. On account of basic principles and evaluation parameters, we firstly highlight the subtle construction for photocathodes to enhance the efficiency and selectivity of CO2 reduction, which includes the strategies for improving light utilization, supplying catalytic active sites and steering reaction ***, diversiform novel PEC setups are also *** exploited setups endow a bright window to surmount the intrinsic disadvantages of photocathode, showing promising potentials for future applications. Finally, we underline the challenges and key factors for the further development of PEC CO2 reduction that would enable more efficient designs for setups and deepen systematic understanding for mechanisms.

摘要：Supports are commonly implemented in the industrial application of heterogeneous catalysts to improve the stability and recyclability of *** supported catalysts often show the enhanced activity and selectivity in various catalytic ***,the specific contributions of electronic and steric effects to a catalytic system often remain elusive due to the lack of well-defined model *** this work,two types of uniform Pd nanocrystals covered by{111}facets in tetrahedral and octahedral shapes,respectively,are synthesized with identical chemical environment and loaded on Ti O_2supports to form hybrid structures(Pd{111}-Ti O_2)towards the application of formic acid *** observation suggests that the polarization effect at the interface of Pd-Ti O_2enhances its activity in formic acid ***,the Pd tetrahedrons-Ti O_2hybrid structure whose Pd{111}-Ti O_2interface possesses a larger angle shows higher catalytic activity,owing to the reduced steric effect as compared to Pd octahedrons-Ti O_*** study reveals the nature of interface effects in formic acid decomposition,and provides a guidance for the related catalyst design.

摘要：Electron-hole separation is a critical step to achieving efficient photocatalysis, towards which use of co-catalysts has become a widely used strategy. Despite the tremendous efforts and demonstrated functions of noble metal co-catalysts, seeking noble metal-free co-catalysts will always be the goal when designing cost- effective, high-performance hybrid photocatalysts. In this work, we demonstrate that MoS~ nanosheets with 1T phase （i.e., octahedral phase） can function as a co-catalyst with multiple merits： （1） Noble-metal-free; （2） high mobility for charge transport; （3） high density of active sites for H2 evolution on basal planes; （4） good performance stability; （5） high light transparency. As demonstrated in both photocatalytic hydrogen production and Rhodamine B degradation, the developed hybrid structure with TiO2 exhibits excellent performance, in sharp contrast to bare TiO2 and the hybrid counterpart with 2H-MoS2.

摘要：A series of mesoporous Ta and Ta-W oxides have been prepared and employed as solid acid catalysts for the dehydration of fructose and glucose to 5-hydroxymethylfurfural(HMF).Solid state 31 P MAS NMR spectroscopic results using trimethylphosphine(TMP)as a probe molecule show that the acid strength and the ratio of Br?nsted to Lewis acid sites increase gradually with the addition of tungsten in tantalum *** is found that high sugar conversion and HMF selectivity are achieved over catalyst with relatively high ratios of Br?nsted to Lewis acid *** stoichiometric excess of formic acid relative to levulinic acid can be observed mainly because of direct decomposition of fructose over Lewis acid *** addition of 2-butanol leads to the increase of sugars conversion and the HMF selectivity,especially for the catalyst with high ratio of Br?nsted to Lewis acid *** them,Ta7W3 oxide catalyst shows 54%HMF selectivity and good reusability with the addition of 2-butanol by extracting HMF from aqueous phase and removing humins deposed on the surface of the catalyst.

摘要：Efficient tandem reactions on a single catalytic nanostructure would be beneficial to improving chemical transformation efficiency and reducing safety implications. It is imperative to identify the active sites for each single step reaction so that the entire reaction process can be optimized by designing and integrating the sites. Herein, hydrogen transfer reaction is taken as a proof-of-concept demonstration to show that the spatial integration of active sites is important to the catalytic efficiency of the entire process in tandem reactions. We identified specific active sites (i.e., various sites at faces versus corners and edges) for formic acid decomposition and alkene/nitrobenzene hydrogenation-the two steps in hydrogen transfer reactions, by employing three different shapes of Pd nanocrystals in tunable sizes. The investigation reveals that the decomposition of formic acid occurs preferentially at the edge sites of cubic nanocrystal and the plane sites of octahedral/ tetrahedral nanocrystals, while the hydrogenation takes place mainly at the edge sites of both cubic and octahedral/ tetrahedral nanocrystals. The consistency of active edge sites during different step reactions enables cubic nanocrystals to exhibit a higher activity than octahedral nanocrystals in hydrogen transfer reactions, although octahedrons offer comparable activities to cubes in formic acid decomposition and hydrogenation reactions. Guided by these findings, we further improved the overall performance of tandem catalysis by specifically promoting the limiting step through nanocatalyst design. This work provides insights into the rational design of heterogeneous nanocatalysts in tandem reactions.

摘要：Researchers have been attempting to characterize heterogeneous catalysts in situ in addition to correlating their structures with their activity and selectivity in spite of many ***,we review recent experimental and theoretical advances regarding alkyne selective hydrogenation by Pd‐based catalysts,which are an important petrochemical *** catalytic selectivity for the reaction of alkynes to alkenes is influenced by the composition and structure of the *** progress achieved through experimental studies and atomic simulations has provided useful insights into the origins of the *** important role of the subsurface species(H and C)was revealed by monitoring the catalyst surface and the related catalytic *** atomic structures of the Pd catalytic centers and their relationship with selectivity were established through atomic *** combined knowledge gained from experimental and theoretical studies provides a fundamental understanding of catalytic mechanisms and reveals a path toward improved catalyst design.

摘要：Carbonyl compounds with elements of C, H, and O and reversible redox-active centers are promising elec- trode materials in rechargeable batteries owing to their high theoretical capacity, structure flexibility and resources abun- dance. However, the low conductivity and the dissolution of active molecules in organic electrolyte limit the practical ap- plication. Immobilizing the carbonyls on graphene provides a simple approach to address these two issues. However, most reported interaction between carbon-based substrates and carbonyl compounds is weak π-π interaction, which is not strong enough to prohibit the detachment of active ma- terials from carbon surface, and thus leading to undesirable cycling performance. Herein, we applied the first principle calculations to study the carbonyls-graphene interaction and found that the weak rc-a interaction can be rationally converted to the strong a-Li-~~ interaction via introducing the groups containing Li atoms. The introduced Li atoms can cooperatively bind with the two aromatic a components through the covalent Li-carbonyl compounds interaction and Li-graphene interaction. The concept of ~（-Li-Tr interaction provides a versatile method to suppress the dissolution of active materials and increase the electronic conductivity at the same time, which gains insight into the design of organic electrode materials for rechargeable batteries with high performance.