摘要：Developing novel electrode materials for li-thium-ion batteries （liBs） with rapid charge/discharge cap- ability and high cycling stability remains a big challenge to date. Herein, we demonstrate the design and synthesis of ul- trathin MoS2 nanosheets in-situ grown on sponge-like carbon nanospheres by a simple diffusion-controiled process. The unique sponge-like carbon nanosphere core can be used as ＂reservoir＂ of electrolyte by adsorbing to shorten the ion- diffusion path, and meanwhile as ＂elastomer＂ to alleviate the structural change of the MoS2 nanosheets during the charge/ discharge processes. Furthermore, the vertical ultrathin MoS2 nanosheets with broadened interlayer space greatly enrich the electrochemical active sites. Consequently, the as-obtained MoS2/C nanospheres exhibit increased specific capacities at various rates with superior cycling stability compared to the MoS2/C floccules. It is reckoned that the present concept can be extended to other electrode materials for achieving high- rate and stable liBs.

摘要：Restraining the aggregation and polysulfide dissolution of edge-enriched metal sulfides is of significance for their applications as anode materials of lithium-ion batteries(liBs)with high capacity and long *** this work,we have reported the incorporation of MoS2 nanocrystals into amorphous carbon on the surface of reduced graphene oxide(rGO)by balancing the decomposition rates of phenolic resin(PF)-impregnated ammonium thiomolybdate(ATM),which subsequently forms the MoS2@C/rGO film through redispersion and vacuum *** structural design effectively avoids the aggregation of MoS2 nanocrystals and li2S loss,and meanwhile ion enrichment in amorphous carbon and diffusion reinforcement can greatly accelerate the electrochemical reaction *** applied as the selfstanding anode,the MoS2@C/rGO film possesses high reversible capacities of 1164 mA h g^-1 at the current density of 0.2 A g^-1 and 810 mA h g^-1 at 6.4 A g^-*** also exhibits quite a high capacity retention after 1000 cycles at 3.2 A g^-*** work develops the formation theory of incorporation structures and promotes their applications in energy storage devices.

摘要：Sodium ions(Na+) and ether electrolyte coinserted graphite possesses a considerable volume expansion effect. However, the mechanism fails to clearly explain its stability. In response to this deficiency, the co-inserted reaction is proposed, which is affected by the Lorentz force of the applied electric field under the high-current condition. The Na^(+) ions are separated out, while the ethylene glycol dimethyl ether molecules remain between the graphite layers. This insight provides a reasonable explanation for the extraordinary stability of this material. In situ X-ray diffraction and density functional theory calculations confirm the separation and release of Na+. On the basis of this result, unmodified commercial graphite was stably cycled 6400 times at a current density of up to 10 A g^(-1), and the capacity retention rate was as high as 97.2%. The full battery assembled in the laboratory has a maximum output power of 14,846 W kg^(-1)and an output energy density of 103 W h kg^(-1)(relative to the weight of anodic and cathodic active materials). The new mechanism provides innovative ideas for the design of large-scale energy storage devices.

摘要：The activation of multisite high-entropy alloy(HEA)electrocatalysts is helpful for improving the atomic utilization of each metal in water electrolysis ***,well-dispersed HEA nanocrystals on Nrich graphene with abundant M–pyridinic N–C bonds were synthesized through an ultrasonic-assisted confinement synthesis *** Raman analysis and density functional theory calculations revealed that the electrocatalysts presented the optimal electronic rearrangement with fast ratedetermined H_(2)O dissociation kinetics and favorable H^(*)adsorption behavior that greatly enhanced hydrogen generation in alkaline electrolyte.A small overpotential of only 138.6 mV was required to obtain the current density of 100 mA cm^(-2) and the Tafel slope of as low as 33.0 mV dec^(-1),which was considerably smaller than the overpotentials of the counterpart with poor M–pyridinic N–C bonds(290.4 mV)and commercial Pt/C electrocatalysts(168.6 mV).The atomic structure,coordination environment,and electronic structure were *** work provides a new avenue toward activating HEA as advanced electrocatalysts and promotes the research on HEA for energy-related electrolysis.

摘要：The creation of Cu^(0)/Cu^(+)interface over Cubased catalysts is known to facilitate the production of multicarbon(C_(2+))products during CO_(2)reduction reaction(CO_(2)RR).However,the Cu^(+)moieties exhibit high susceptibility towards reduction into Cu^(0)at a high current ***,a comprehensive understanding and rational shaping strategy for the construction and stabilization of Cu^(0)/Cu^(+)interface in Cu-based catalysts is ***,we proposed a controllable“nanoparticle assembly”strategy to obtain hollow spherical assemblies(HSA)composed of numerous Cu_(2)O nanoparticles(HSA-Cu_(2)O).The HSA-Cu_(2)O catalysts significantly enhance the selectivity of C_(2+)products,resulting in an impressive overall Faraday efficiency(FE)of 79.2%±0.7%at a partial current density of 317.1 mA cm−*** HSA-Cu_(2)O catalysts undergo in-situ electrochemically reconstruction during CO_(2)RR,achieving Cu^(0)/Cu^(+)interfacial sites with a high *** Auger electron spectra,in-situ Raman,and morphological evolution studies have confirmed that the combination of the Cu^(0)/Cu^(+)interface and hollow sphere architecture facilitated the concentration of*CO intermediates,thereby promoting C–C dimerization to boost C_(2+)selectivity in CO_(2)RR.

摘要：为应对气候与环境变化及适应未来工业生产需求,近年来,H_(2)O,CO_(2)以及有机小分子等的电催化还原或氢化反应受到广泛的关注.但阳极析氧反应(OER)的缓慢动力学过程导致反应能耗高,限制了其实际应用.近年来,研究人员采用热力学上更有利的亲核氧化反应(NOR)代替OER,并与阴极半反应耦合,进而降低总体能耗,同时在阳极获得高附加值产物.其中,设计高效、稳定、易放大制备的催化剂是实现NOR工业化应用的关键.本文采用简便且易于规模化生产的策略制备电催化剂,并用于甲醇氧化反应(MOR).首先,采用沉淀法制备镍钼氧化物水合物和钴钼氧化物水合物;随后,将两种水合物按一定比例物理混合得到MOR催化剂.实验结果表明,混合物中的镍钴两种组分在含有KOH的碱性电解液中快速脱钼并转变为氢氧化物.当混合物中NiMo氧化物与CoMo氧化物的质量比为1:1(记为Ni50Co50-m)时,材料表现出最佳的催化活性.Ni50Co50-m在1 mol L^(–1)KOH+1 mol L^(–1)甲醇电解液中达到100 mA cm^(–2)电流密度仅需约1.51 V施加电位,活性及阳极反应选择性均远远高于单一组分.相比于化学共沉淀法所制备的NiCoMo氧化物,Ni50Co50-m表现出更好的稳定性.为明确混合物催化性能比单一组分材料大幅提高的原因,通过现场原位电化学阻抗谱和工况原位拉曼光谱对单一组分催化剂在服役条件下的反应界面以及催化剂结构演变进行研究.结果表明,单一镍组分催化剂在MOR过程中会被部分氧化为NiOOH,但是由于镍组分导电性很差,电荷转移微弱,因此催化性能较差.单一钴组分催化剂在MOR过程中表面被氧化为CoOOH,OER和MOR均发生在CoOOH表面,但是钴组分的本征活性并不强且对竞争反应OER的选择性较高.通过比较真实混合物(Ni50Co50-m)以及镍钴组分间无接触情况下的原位阻抗谱响应,证明了镍与钴之间存在相互作用.混合物中镍钴组分接触界面间的相互作用包括以下两个方面:一方面,钴组分在一定的外加电压下被氧化为导电良好的CoOOH,其作为混合物中的电荷传输媒介,激活更多的镍位点参与到催化剂的电氧化过程中,增大了Ni^(2+)/Ni^(3+)氧化还原物种的覆盖度,为催化活性物种OH*的形成提供了更多位点;另一方面,镍钴组分之间的相互作用影响了Ni2+的电氧化行为,Ni^(2+)的氧化电位明显下降,钴组分的引入降低了Ni^(3+)‒O键的电子云密度,使得OH–向Ni^(3+)位点的亲核进攻变得更加有利,进而促进了OH*的产生及其与镍位点的紧密结合,从而提高了MOR的活性和选择性.综上,本文通过混合物中镍与钴组分间的界面相互作用提升了催化剂对MOR的催化活性.该混合增强策略同样适用于其他NOR(如乙醇氧化反应、乙二醇氧化反应等)以及其他镍基催化剂(如氢氧化镍、硫化镍).本工作为简便、高效和放大制备NOR催化剂提供了新思路.

摘要：生物质是世界上广泛存在的可再生资源,可以转化成高价值燃料和化学品.基于可再生能源产生的电力,将生物质衍生的5-羟甲基糠醛(HMF)电催化转化为2,5-呋喃二甲醇(BHMF)具有重要的研究意义和应用价值.HMF在电转化过程中容易发生二聚反应,从而导致BHMF的选择性较低,产物分离难度大.因此,探索获得高选择性BHMF的高效催化体系极为重要.在此,本文报道了Rh掺杂的Cu纳米线催化剂,其在HMF电还原为BHMF反应中表现出较高的转化率,且有效抑制了二聚反应的发生.动力学实验和原位光谱研究表明,Rh的引入可以有效促进水解离形成活性氢物种,促进5-羟甲基糠醛电催化加氢并抑制其二聚.此催化剂设计策略可以拓展到其他生物质衍生分子的电催化转化过程中.

摘要：在电解水制氢过程中,为了在低电位下获得超高电流密度,其关键在于打破氧生成反应的标度关系.本文中,我们设计了一种新型异质界面功能化的NiFe(OH)_(x)/Ni_(3)S_(2)电催化剂,成功地规避了析氧反应(OER)的标度关系,使ΔGHOO*-ΔGHO*的差值从3.20 eV降低到2.38 eV.所制备的NiFe(OH)_(x)/Ni_(3)S_(2)电催化剂仅需要310 mV的过电位即可获得2000 mA cm^(-2)的超高电流密度, Tafel斜率仅为20.8 mV dec^(-1).此外,在1000 mA cm^(-2)的电流密度下,稳定运行100小时后无明显的活性损失,该性能优于目前报道的OER催化剂.进一步利用密度泛函理论计算和实验结果揭示了并联催化作用机制,发现多种中间体吸附能均一化能够优化OER反应路径,从而提升超高电流密度下的OER催化性能.本文的研究结果对开发工业级高性能水分解电催化剂具有重要的指导意义.

摘要：随着可再生能源发电成本的持续下降和电催化技术的迅猛发展,人们开始重新审视能源燃料和化学品的生产方式.近年来,H2O和CO_(2)等小分子的电催化转化反应已成为研究热点.特别是,CO_(2)还原反应(CO_(2)RR)作为将CO_(2)电化学还原为高附加值产品的一项变革性的技术,备受关注.在CO_(2)RR的众多产物中,CO具有重要的地位,它可以通过费托合成工艺直接用于合成醇、醛、酮、酸及烃等化工产品.然而,将CO_(2)电催化转化为CO在整体效率方面仍面临诸多挑战.因此,设计并制备高效、经济且耐用的电催化剂已成为CO_(2)RR领域发展的研究重点.本文采用简单的配体辅助负载策略制备了铜单原子修饰的铜原子簇催化剂(Cu SA/ACs).球差校正的高角度环形暗场扫描透射电子显微镜结果表明,铜以单原子和原子簇的形式存在.采用X射线吸收精细结构谱和X射线光电子能谱(XPS)分析了铜原子的电子和配位结构,证明了Cu-N键和Cu-Cu键的存在.电化学性能测试表明,与铜单原子催化剂(Cu SACs)相比,Cu SA/ACs催化剂展现了较好的CO_(2)RR性能,其CO的转化法拉第效率从27.15%提高到98.94%,电流密度是Cu SACs的3.6倍.此外,将该催化剂组装成流动电解池,在600 mA cm-2的高电流密度下,CO选择性达到93.06%,阴极的最高能量效率达61.9%,优于大多数CO_(2)还原制备CO的催化剂.为了明确铜单原子组分引入对铜原子簇性能提升的原因,通过电化学原位红外光谱研究催化剂在服役条件下的表面物种吸附.结果表明,Cu SACs催化剂的单原子活性中心在CO_(2)RR过程中受到H2析出反应的困扰,活性中心表面的吸附物种主要为H2O而不是CO_(2),从而导致CO_(2)还原性能较差;在Cu SA/ACs催化剂表面,其活性中心由单原子和原子簇协同组成,CO_(2)主要吸附在原子簇上,单原子和原子簇协同作用促进了H2O的解离过程,为CO_(2)质子化提供丰富的活性氢,进一步加快CO_(2)RR的反应动力学.密度泛函计算和差分电荷密度分析结果表明,单原子的引入优化了原子簇的局域电子结构,诱导d带中心靠近费米能级,从而优化了*COOH中间体的形成能和CO的脱附过程.综上,本文通过合理的活性位点设计实现了多位点的耦合协同,提升了铜基催化剂对于CO_(2)RR的催化活性,优化了铜基催化剂上CO_(2)到CO的选择性,通过机理研究加深了对铜基催化剂上CO_(2)转化模式的认识,为设计高效催化剂提供新思路.

摘要：基于多巴胺易于成膜且其聚合物具有丰富官能基团的特性,通过在介孔碳中嵌入高分散性的Ag纳米晶,设计制备了嵌有Ag纳米晶的介孔碳/Mn O(Mn O/Ag@MC)共轴纳米复合材料并作为锂离子电池负极材料.所制备的Mn O/Ag@MC核壳纳米线平均直径约80nm,碳层厚度约20 nm,Ag纳米晶(<10 nm)均匀地嵌在碳层内部.Ag纳米晶嵌入的介孔碳层包覆可以增强氧化锰的电化学活性,循环充放电能力以及快速的电子传递和离子传输速率.与无Ag纳米晶的Mn O/MC核壳纳米线、纯Mn O纳米线相比,当前所制备的Mn O/Ag@MC核壳结构纳米线的电化学性能得到了显著提升.当电流密度为100 m A g-1时,放电比容量可以达到673 m A h g-1,即使在电流密度高达3000 m A g-1时,比容量仍保持291.2 m A h g-1.此外,在500 m A g-1电流密度时经过200次连续充放电测试后,其比电容量仍保持478.2 m A h g-1.所制备Mn O/Ag@MC复合纳米线有希望成为锂离子电池负极材料.