摘要：single-atom catalysts(SACs),with atomically dispersed metal atoms anchored on a typical support,representing the utmost utilization effi ciency of the atoms,have recently emerged as promising catalysts for a variety of catalytic *** electronic properties of the active center of SACs are highly dependent on the local environment constituted by the single metal atom and its surrounding coordination ***,engineering the coordination environment near single metal sites,from the fi rst coordination shell to the second shell or higher,would be a rational way to design effi cient SACs with optimized electronic structure for catalytic *** wide range of coordination confi gurations,guaranteed by the multiple choices of the type and heterogeneity of the coordination element(N,O,P,S,etc.),further off er a large opportunity to rationally design SACs for satisfactory activities and investigate the structure-performance *** this review,the coordination engineering of SACs by varying the type of coordination element was elaborated and the photocatalytic water splitting of SACs was ***,challenging issues related to the coordination engineering of SACs and their photocatalytic applications were discussed to call for more eff orts devoted to the further development of single-atom catalysis.

摘要：The polysulfide shuttling effect is the primary bottleneck restricting the industrial application of Li-S batteries,and the electrocatalytic sulfur reduction reaction(SRR)has emerged as an effective ***-based singleatom catalysts(SACs),which promotes SRR,show great potential in inhibiting the shuttling effect of ***,the optimization and rational design of such catalysts requires a deep understanding to the fundamental SRR mechanism and remains highly *** this work,we construct a comprehensive database of carbon-based SACs,covering different coordination patterns,heteroatoms,and transition *** SRR activities are determined using density functional theory calculations,revealing a synergistic effect between the p orbital of the heteroatom and the d orbital of the transition *** interplay underscores the critical importance of the coordination environment for SRR under the ortho-P_(2)C_(2)*** of the transition metal type,the ortho-P_(2)C_(2)coordination pattern significantly enhances the SRR performance of SACs,surpassing the widely reported N_(3)C_(1)and N_(4)coordinated graphene-based ***,heteroatoms with ortho-P_(2)C_(2)may exhibit SRR *** a word,by using this comprehensive dataset and data-driven framework,we propose a promising novel class of coordination structure(ortho-P_(2)C_(2)structure)and neglected design principle.

摘要：The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2) reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into the symmetric nickel-nitrogen-carbon(Ni-N_(4)-C)configuration to obtain Ni-X-N_(3)-C(X:S,Se,and Te)SACs with asymmetric coordination presented for central Ni *** these obtained Ni-X-N_(3)-C(X:S,Se,and Te)SACs,Ni-Se-N_(3)-C exhibited superior eCO_(2)RR activity,with CO selectivity reaching~98% at-0.70 V versus reversible hydrogen electrode(RHE).The Zn-CO_(2) battery integrated with Ni-Se-N_(3)-C as cathode and Zn foil as anode achieved a peak power density of 1.82 mW cm^(-2) and maintained remarkable rechargeable stability over 20 ***-situ spectral investigations and theoretical calculations demonstrated that the chalcogen heteroatoms doped into the Ni-N_(4)-C configuration would break coordination symmetry and trigger charge redistribution,and then regulate the intermediate behaviors and thermodynamic reaction pathways for eCO_(2)***,for Ni-Se-N_(3)-C,the introduced Se atoms could significantly raise the d-band center of central Ni atoms and thus remarkably lower the energy barrier for the rate-determining step of ^(*)COOH formation,contributing to the promising eCO_(2)RR performance for high selectivity CO production by competing with hydrogen evolution reaction.

摘要：Large-scale production of polyethylene in industry requires efficient elimination of the trace amount of acetylene ***,zeolite adsorption or the conversion of acetylene to ethylene via selective semi-hydrogenation on Pd catalysts is the commonly used *** this work,we investigate the reaction mechanisms of acetylene hydrogenation on defective graphene(DG)supported singleatom catalysts(SACs),M1/SV-G and M1/DV-G(M=Ni,Pd and Pt)using density functional theory(DFT),where SV-G and DV-G represent DG with single and double vacancies,*** is shown that the metal single-atoms(SAs)as well as their different coordination numbers both affect the activity and selectivity of the hydrogenation process.M1/DV-G provides better H2 dissociation ability than M1/SV-G,which accounts for the poor acetylene hydrogenation activity of M1/*** on the reaction barriers,Pt1/DV-G and Ni1/DV-G are better catalysts than other systems considered here,with Ni1/DV-G exhibiting high selectivity for the semi-hydrogenation product of *** results provide insights for the design of highly selective and noble-metal-free SACs for acetylene hydrogenation on carbon materials.

摘要：Fe/N/C material is the most competitive alternative to precious-metal catalysts for oxygen *** view of the present consensus on active centers,further effort is directed at maximizing the density of single Fe ***,the imperfections in commonly used doping strategy of Fe for the synthesis of zeolitic imidazolateframework(ZIF)-derived Fe/N/C catalysts are *** importantly,a strikingly improved catalyst is obtained by a‘second pyrolysis’method and delivers a half-wave potential of 0.825 V(***)in acidic *** strong confinement effect of carbonaceous host accounts for the formation of dense single-atom sites and thus the high *** findings will potentially facilitate future improvement of M/N/C catalysts.

摘要：Lithium carbon dioxide(Li-CO_(2))batteries deliver a theoretical energy density of 1876 W h kg^(-1) in terms of effective utilization of greenhouse *** battery system is considered to be an encouraging electrochemical energy storage device and a promising alternative to Li-ion ***,the main drawback of Li-CO_(2) batteries is their accumulative discharge product of Li_(2)CO_(3)/C,which leads to large overpotential and poor cycling ***,specific and efficient catalysts must be explored to enhance the decomposition of Li_(2)CO_(3)/***-atom catalysts(SACs)are regarded as promising heterogeneous catalysts owing to their maximized utilization of metal atoms and strong interfacial electronic ***,single-metal atoms of Fe,Co,and Ni uniformly anchored on N-doped reduced graphene oxide(rGO),designated as Fe_(1)/N-rGO,Co1/N-rGO,and Ni_(1)/N-r GO,respectively,are designed and fabricated to investigate their catalytic activity toward the decomposition of Li_(2)CO_(3)/*** them,Fe_(1)/N-rGO delivers a high discharge capacity of 16,835 mA h g^(-1) at 100 mA g^(-1) and maintains stability for more than 170 cycles with a discharge voltage of 2.30 V at 400 mA g^(-1).Therefore,this catalysts are overwhelmingly superior to other *** work reveals the advances of SACs in Li-CO_(2) batteries and offers an effective method for realizing high-performance Li-CO_(2) batteries.

摘要：single-atom catalysts(SACs) with well-defined and specific single-atom dispersion on supports offer great potential for achieving both high catalytic activity and selectivity. Covalent organic frameworks(COFs) with tailormade crystalline structures and designable atomic composition is a class of promising supports for SACs. Herein, we have studied the binding sites and stability of Pd single atoms(SAs)dispersed on triazine COF(Pd1/trzn-COF) and the reaction mechanism of CO oxidation using the density functional theory(DFT). By evaluating different adsorption sites, including the nucleophilic sp2C atoms, heteroatoms and the conjugated π-electrons of aromatic ring and triazine, it is found that Pd SAs can stably combine with trzn-COF with a binding energy around-5.0 eV, and there are two co-existing dynamic Pd1/trzn-COFs due to the adjacent binding sites on trzn-COF. The reaction activities of CO oxidation on Pd1/trzn-COF can be regulated by the anion–π interaction between a +δ phenyl center and the related-δ moieties as well as the electron-withdrawing feature of imine in the specific complexes. The Pd1/trzn-COF catalyst is found to have a high catalytic activity for CO oxidation via a plausible tri-molecular Eley-Rideal(TER) reaction mechanism. This work provides insights into the d–π interaction between Pd SAs and trznCOF, and helps to better understand and design new SACs supported on COF nanomaterials.

摘要：电化学二氧化碳还原反应(CO_(2)RR)通过将CO_(2)转化为高价值化学品和燃料来降低其在大气中的浓度,是解决能源危机的重要途径.因此,合理设计高效、经济的电化学催化剂至关重要.研究发现,铜(Cu)是一种性能优越的金属催化剂,可将CO_(2)还原成碳氢化合物和醇类,尤其是C_(2+)产物.然而,Cu催化剂也存在一定问题(如过电位高和CO_(2)RR选择性差等),从而限制了其应用.近年来,单原子催化剂(SACs)因其具有高活性、高选择性和高稳定性,已成为异相催化剂领域的新兴研究前沿.本文总结了CO_(2)RR的各种铜基SACs的最新研究进展,尤其是活性位点与关键反应中间产物相互作用的调控策略.这种相互作用对于设计活性位点以及优化多电子还原步骤和提高催化性能非常重要.同时,本文还讨论了金属中心调控、铜基单原子合金催化剂、非金属SACs、串联催化剂和复合催化剂等研究前沿.最后,总结了SACs应用于CO_(2)RR的挑战与展望.

摘要：电催化硝酸根还原制氨是调节全球氮循环和合成氨的一种很有前景的方法.当前实现高效硝酸根还原制氨(NRA)的关键问题是开发具有高活性、选择性和稳定性的催化剂.本文通过把过渡金属(TM:3d=Sc-Zn,4d=Y-Cd,5d=La-Hg)锚定在二维材料Ti_(3)C_(2)O_(2)MXene(Ti_(3)C_(2)O_(2)-TM)上,筛选出新的NRA单原子催化剂.本工作采用密度泛函理论进行理论计算,发现Ti_(3)C_(2)O_(2)上的表面O官能团对TM具有较高的锚定能力,同时材料拥有良好的抗溶解稳定性.此外,锚定的TM与硝酸根之间强的p-d耦合作用使NO_(3)-易于活化.锚定TM在费米能级处有较高的不饱和d轨道,具有良好的稳定性和NO_(3)-活化能力.基于此,本文筛选出10种前线分子轨道在d5附近的Ti_(3)C_(2)O_(2)-TMs(TM=Cr,Mn,Fe,Tc,Ru,W,Re,Os,Ir,Pt),并且最有利的反应路径是持续的脱氧加氢:NO_(3)-→*NO_(3)→*NO_(2)→)*NO→*N→*NH→*NH_(2)→*NH_(3)→NH_(3)(g).本工作认为Ti_(3)C_(2)O_(2)-CrSA、Ti_(3)C_(2)O_(2)-ReSA和Ti_(3)C_(2)O_(2)-OsSA这3种具有低NRA过电位的Ti_(3)C_(2)O_(2)-TM是优异的NRA催化剂.这些发现为设计低能耗、低碳排放的先进氨合成路线提供了新策略.