摘要：在过去几十年中,将二氧化碳光还原转化为有用的化学燃料(甲烷、一氧化碳和甲醇等)受到了极大的关注.然而,由于光生电荷的复合速度快,二氧化碳和水分子的共吸附不足,目前的二氧化碳光还原系统的效率还远远不能令人满意.本文报道了在疏水碳纤维纸上构建一个紧密的二维/二维石墨相氮化碳@碘氧铋梯型(S型)异质结,用于高效的二氧化碳光还原.所制备的异质结具有良好的一氧化碳选择性(77.8%)和活性(458.0μmol h^(-1)m^(-2)).良好的光催化性能归因于良好设计的S型异质结结构,提高了电荷分离效率,以及形成了气-液-固三相界面,充分保证了二氧化碳和水的同时供给.这项工作为高效光催化二氧化碳还原系统的设计提供了新思路.

摘要：氧化钼(MoO_(3))是一种具有吸引力的锂离子电池(LIBs)负极材料;然而,其导电性低、锂化后体积膨胀大、锂离子扩散动力学缓慢等特点严重限制了其实际应用.本文中,我们利用高量Mo/N掺杂的碳前驱材料合成了超细的MoO_(3)纳米颗粒(NPs,10–15 nm),所合成的MoO_(3)NPs被限制在原位生成的N掺杂碳网络结构中.这种设计既促进了快速的电子传导,又缩短了锂离子扩散路径;同时,MoO_(3)表面丰富的氮物种和氧缺陷有助于降低锂离子的吸附能垒,这些共同支持了MoO_(3)NPs在高电流倍率下耐久储锂性能的提升.值得注意的是,所获得的NCMoO_(3)纳米复合材料表现出1362 mA h g^(−1)(0.1 A g^(−1))的较高容量,并在10.0 A g^(−1)时保持394 mA h g^(−1)的可逆容量.全电池测试表明:在大倍率5 C下,LiFePO_(4)//NC-MoO_(3)-400电池仍可以输出81 mA h g^(−1)的比容量.我们的工作有望启发其他嵌入导电碳网络的过渡金属氧化物的设计合成及其在LIBs中的实际应用.

摘要：Currently adopted cross-linking methods in rubber industry are suffering from variable persistent issues, including the utilization of toxic curing packages, release of volatile organic compounds (VOCs) and difficulties in the recycling of end-of-life materials. It is of great importance to explore a green cross-linking strategy in the area. Herein, we report a new ‘‘green" strategy based on hydrolyzable ester cross-links for cross-linking diene-typed elastomers. As a proof of concept, a commercial carboxylated nitrile rubber (XNBR) is efficiently cross-linked by a bio-based agent, epoxidized soybean oil (ESO), without any toxic additives. ESO exhibits an excellent plasticization effect and excellent scorch safety for XNBR. The crosslinking density and mechanical properties of the ESO-cured XNBR can be manipulated in a wide range by changing simply varying the content of ESO. In addition, zinc oxide (Zn O) performs as a catalyst to accelerate the epoxide opening reaction and improve the cross-linking efficiency, serving as reinforcement points to enhance the overall mechanical properties of the ESO-cured XNBR. Furthermore, the end-oflife elastomer materials demonstrate a closed-loop recovery by selectively cleaving the ester bonds, resulting in very high recovery of the mechanical performance of the recycled composites. This strategy provides an unprecedented green avenue to cross-link diene elastomers and a cost-effective approach to further recycle the obtained cross-linked elastomers at high efficiency.

摘要：The demanding all-in-one electrocatalyst system for oxygen reduction reaction(ORR), oxygen evolution reaction(OER) and hydrogen evolution reaction(HER) in zinc-air batteries or water splitting requires elaborate material manufacturing, which is usually complicated and *** interface engineering between MXene and highly active electrocatalytic species(CoS_(2)) is, herein, achieved by an in situ hydrothermal growth and facile sulfurization *** CoS_(2)@MXene electrocatalyst is composed by one-dimensional CoS_(2) nanowires and two-dimensional MXene nanosheets, which lead to a hierarchical structure(large specific surface area and abundant active sites), a spatial electron redistribution(high intrinsic activity), and high anchoring strength(superior performance stability). Therefore, the electrocatalyst achieves enhanced catalytic activity and longtime stability for ORR(a half-wave potential of 0.80 V), OER(an overpotential of 270 mV at 10 mA cm^(-2), i.e., η10= 270 mV)and HER(η10= 175 mV). Furthermore, the asymmetry water splitting system based on the CoS_(2)@MXene composites delivers a low overall voltage of 1.63 V at 10 mA cm^(-2). The solidstate zinc-air batteries using CoS_(2)@MXene as the air cathode display a small charge-discharge voltage gap(0.53 V at1 mA cm^(-2)) and superior stability(60 circles and 20-h continuous test). The energy interconversion between the chemical energy and electricity can be achieved by a self-powered system via integrating the water splitting system and quasisolid-state zinc-air batteries. Supported by in situ Raman analyses, the formation of cobalt oxyhydroxide species provides the active sites for water oxidation. This study paves apromising avenue for the design and application of multifunctional nanocatalysts.

摘要：The commercialization of proton exchange membrane fuel cells(PEMFCs) is still restricted by the well-known dilemma,that is,the heavy dependence of using expensive plantinum(Pt) catalyst to negotiate the sluggish oxygen reduction reaction(ORR) kinetics in fuel cell ***,a carbon-supported PtC o2Ni2 alloy catalyst with low Pt usage was synthesized via a simple method,which exhibited exceptional ORR activity with a more positive half-wave potential(E1/2) ~57 m V,which was more positive than the state-of-the-art Pt/C ***,the alloy catalyst performs excellent durability after 10,000 harsh cycles compared with that of Pt/C catalyst in acidic solution,which may be developed as a promising alternative for Ptbased catalysts in fuel cell technology.

摘要：通过设计特定的时空调制,合成磁性的概念最近被提出以实现对光子和声子等电荷中性粒子的非互易操控,但现有方案存在着隔离度低、信号频率变化等问题.本文设计了一种新型耦合共振腔系统,其中动态耦合的相位作为实现声学合成磁场的新机制并打破了系统的时间反演对称性,最终取得了优异的声波非互易传输.基于旋转波近似方法,作者严格推导出了实现系统强非互易声传输的参数条件.通过优化动态耦合之间的相位差以及耦合强度,实验展示了隔离度达45-dB和正向传输率达0.85的优异单向声传输.此外,这种单向声传输具有始末态频率不变和隔离方向可电控等重要特性.该研究突破了现有声波单向操控机制在效率和隔离度方面的局限,并为实现弗洛奎和非线性声学拓扑绝缘体提供了新途径.

摘要：Combining a progressive tandem junction design with a unique Si nanowire(SiNW)framework paves the way for the development of high‐onset‐potential photocathodes and enhancement of solar hydrogen ***,a radial tandem junction(RTJ)thin film water‐splitting photo‐cathode has been demonstrated experimentally for the first *** photocathode is directly fab‐ricated on vapor‐liquid‐solid‐grown SiNWs and consists of two radially stacked p‐i‐n junctions,featuring hydrogenated amorphous silicon(a‐Si:H)as the outer absorber layer,which absorbs short wavelengths,and hydrogenated amorphous silicon germanium(a‐SiGe:H)as the inner layer,which absorbs long *** randomly distributed SiNW framework enables highly efficient light‐trapping,which facilitates the use of very thin absorber layers of a‐Si:H(~50 nm)and a‐SiGe:H(~40 nm).In a neutral electrolyte(pH=7),the three‐dimensional(3D)RTJ photocathode delivers a high photocurrent onset of 1.15 V *** reversible hydrogen electrode(RHE),accompanied by a photocurrent of 2.98 mA/cm^(2) at 0 V ***,and an overall applied‐bias photon‐to‐current effi‐ciency of 1.72%.These results emphasize the promising role of 3D radial tandem technology in developing a new generation of durable,low‐cost,high‐onset‐potential photocathodes capable of large‐scale implementation。

摘要：粉末床熔融增材制造技术已应用于功能梯度材料的制造.文献中报道了一种材料成分沿垂直于粉末铺粉方向变化的新设计.基于此设计,本工作采用离散单元数值模拟研究了两种密度差异较大的金属粉末在铺粉过程中颗粒的偏析情况.结果发现,在铺粉过程中,较大密度粉末(重颗粒)一侧的铺粉量小于较小密度粉末(轻颗粒)的一侧的铺粉量.这种现象表明重颗粒从粉末密度大的一侧向粉末密度较小的一侧扩散.这种扩散受铺粉速度影响较大,铺粉速度越快,扩散越明显.但粉末层厚度对扩散影响不大.结果还表明,重颗粒与轻颗粒间的粒径差异影响扩散较大,减小重颗粒的粒径可能是控制颗粒偏析的一种方案.

摘要：Precise control of the local environment and electronic state of the guest is an important method of controlling catalytic activity and reaction *** this paper,guest Pd NPs were introduced into a series of host UiO-67 MOFs with different functional ligands and metal nodes,the microenvironment and local electronic structure of Pd is modulated by introducing bipyridine groups and changing metal nodes(Ce_(6)O_(6) or Zr_(6)O_(6)).The bipyridine groups not only promoted the dispersion Pd NPs,but also facilitated electron transfer between Pd and UiO-67 MOFs through the formation of Pd-N *** with Zr6 clusters,the tunability and orbital hybridisation of the 4f electronic structure in the Ce_(6) clusters modulate the electronic structure of Pd through the construction of the Ce-O-Pd *** optimal catalyst Pd/UiO-67(Ce)-bpy presented excellent low-temperature activity towards dicyclopentadiene hydrogenation with a conversion of>99% and a selectivity of>99%(50℃,10 bar).The results show that the synergy of Ce-O-Pd and Pd-N promotes the formation of active Pd^(δ+),which not only enhances the adsorption of H_(2) and electron-rich C=C bonds,but also contributes to the reduction of proton migration distance and improves proton utilization *** results provide valuable insights for investigating the regulatory role of the host MOFs,the nature of host-guest interactions,and their correlation with catalytic performance.

摘要：Flexible thin-film organic semiconductor devices have received wide attention due to favorable properties such as light-weight,flexibility,reproducible semiconductor resources,easy tuning of functional properties via molecular tailoring,and low cost large-area *** them,ultraflexible electronics,usually with minimum bending radius of less than 1 mm,are essential for the development of epidermal and bio-implanted electronics,wearable electronics,collapsible and portable electronics,three dimensional(3D) surface compilable electronics,and *** review firstly gives a brief introduction of development from flexible to ultraflexible organic semiconductor electronics,and design of ultraflexible devices,then summarizes the recent advances in ultraflexible thin-film organic semiconductor devices,focusing on organic field effect transistors,organic light-emitting diodes,organic solar cells and organic memory devices.