Gong Wanbing, Mao Xin, Zhang Jifang, Lin Yue, Zhang Haimin, Du Aijun, Xiong Yujie, Zhao Huijun
Key Laboratory of Materials Physics, Centre for Environmental and Energy Nanomaterials, Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, P.R. China.
Hefei National Research Center for Physical Sciences at the Microscale, School of Chemistry and Materials Science, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), University of Science and Technology of China, Hefei, Anhui 230026, P.R. China.
ACS Nano. 2023 Feb 28;17(4):3984-3995. doi: 10.1021/acsnano.2c12839. Epub 2023 Feb 14.
In theory, electrocatalysts in their metallic forms should be the most stable chemical state under cathodic potentials. It is known that the highly dispersed nanoparticle (NP) types of electrocatalysts often possess higher activity than their bulk counterparts. However, facilely and controllably fabricating well-dispersed nonprecious metal NPs with superior electrocatalytic activity, selectivity, and durability is highly challenging. Here, we report a facile reductive pyrolysis approach to controllably synthesize NiCo alloy NPs confined on the tip of N-doped carbon nanotubes (N-CNTs) from a bimetal-MOF precursor. The electrocatalytic performance of the resultant NiCo@N-CNTs are evaluated by a wide spectrum of nitroarene reductive coupling reactions to produce azoxy-benzenes, a class of precious chemicals for textile, food, cosmetic, and pharmaceutical industries. The superior electrocatalytic stability, full conversion of nitroarenes, >99% selectivities, and >97% faradic efficiencies toward the targeted azoxy-benzene products are readily attainable by NiCo@N-CNTs, attributable to the alloying-induced synergetic effect. The presence of a CNT confinement effect in NiCo@N-CNTs induces high stability. This added to the metallic states of NiCo empowers NiCo@N-CNTs with excellent electrochemical stability under reductive reaction conditions. In an effort to enhance the energy utilization efficiency, we construct a NiCo@N-CNTs||Ni(OH)/NF two-electrode electrolyzer to simultaneously reduce nitrobenzene at the cathode and 5-hydroxymethylfurfural with >99% yields for both azoxy-benzene and 2,5-furandicarboxylic acid.
理论上，金属形态的电催化剂在阴极电位下应处于最稳定的化学状态。众所周知，高度分散的纳米颗粒（NP）型电催化剂通常比其块状对应物具有更高的活性。然而，轻松且可控地制备具有优异电催化活性、选择性和耐久性的高度分散的非贵金属NP极具挑战性。在此，我们报道了一种简便的还原热解方法，可从双金属MOF前驱体可控地合成限制在N掺杂碳纳米管（N-CNTs）尖端的NiCo合金NP。通过一系列硝基芳烃还原偶联反应来评估所得NiCo@N-CNTs的电催化性能，以生产氧化偶氮苯，这是一类用于纺织、食品、化妆品和制药行业的珍贵化学品。NiCo@N-CNTs易于实现优异的电催化稳定性、硝基芳烃的完全转化、>99%的选择性以及对目标氧化偶氮苯产物>97%的法拉第效率，这归因于合金化诱导的协同效应。NiCo@N-CNTs中存在的CNT限制效应诱导了高稳定性。这与NiCo的金属态相结合，使NiCo@N-CNTs在还原反应条件下具有出色的电化学稳定性。为了提高能量利用效率，我们构建了一个NiCo@N-CNTs||Ni(OH)/NF双电极电解槽，用于在阴极同时还原硝基苯以及将5-羟甲基糠醛分别以>99%的产率转化为氧化偶氮苯和2,5-呋喃二甲酸。
