近日，中国科学技术大学谢毅及其研究团队的最新研究揭示了Ni/C杂化纳米片上的双纳米岛可通过高效活化肼氧化辅助氢气生成。相关论文于2021年10月20日发表在《德国应用化学》杂志上。

研究人员首先在Ni/C杂化纳米片阵列上构建了新型双纳米岛：一种岛体代表裸露的Ni粒子表面部分，另一种岛体代表Ni@C核壳结构(简称Ni-C HNSA)的部分，其中暴露的Ni原子和Ni修饰的碳壳分别作为肼氧化反应(HzOR)和析氢反应(HER)的活性位点。与此同时，Ni@C岛中Ni的电子将转移到C层，引起C层周围电子密度的变化，从而加速HER的动力学过程。

当电流密度达到10 mA·cm^-2  时，HER的过电位仅为37 mV, HzOR的工作电位低至-20 mV。双电极电解槽表现出极好的活性，只需要0.2 V的超小电池电压就可以达到50 mA·cm^-2 的电流密度。这一发现无疑为高级双功能电催化剂的设计提供了新的思路，并推动了实用的节能产氢技术的发展。

据了解，通过电化学裂解水的清洁析氢是各种追求可持续的能量转换技术的创新方法的重点，但它被水裂解中缓慢的阳极析氧反应(OER)所阻碍。肼氧化反应(HzOR)被认为是提高析氢反应(HER)效率最有希望的替代OER的方法之一，但结合高效HER和HzOR活性的精确双功能催化剂的设计意义重大而又稀缺。

附：英文原文

Title: Dual Nanoislands on Ni/C Hybrid Nanosheet Activate Superior Hydrazine Oxidation Assisted High-efficient H2 Production

Author: Yi Xie, Yin Zhu, Jihua Zhang, Qizhu Qian, Yapeng Li, Ziyun Li, Yi Liu, Chong Xiao, Genqiang Zhang

Issue&Volume: 2021-10-20

Abstract: Clean hydrogen evolution through electrochemical water splitting underpins various innovative approaches to the pursuit of sustainable energy conversion technologies, but it is blocked by the sluggish anodic oxygen evolution reaction (OER) during the water splitting. The hydrazine oxidation reaction (HzOR) has been considered to be one of the most promising substitute for OER to improve the efficiency of hydrogen evolution reaction (HER), however, the design of precise bifunctional catalysts which could integrate the high-efficient HER and HzOR activity is significant yet scarce. Herein, we originally construct novel dual nanoislands on Ni/C hybrid nanosheet array: one kind of island represents the part of bare Ni particle surface, while the other stands for the part of core-shell Ni@C structure (denoted as Ni-C HNSA), in which exposed Ni atoms and Ni-decorated carbon shell perform as active sites for HzOR and HER respectively. Simultaneously, the electrons of Ni in Ni@C islands will transfer to the C layer, causing the change of the electron density around the C layer, thereby accelerating the kinetics of HER. As a result, when the current density reaches 10 mA cm -2  , the overpotential of HER is merely 37 mV and the working potential of HzOR is as low as -20 mV. A two-electrode electrolyzer exhibits superb activity that only requiring an ultrasmall cell voltage of 0.2 V to achieve 50 mA cm -2  . This finding undoubtedly provides a new perspective for design of advanced bifunctional electrocatalysts, and propels the practical energy-saving H 2  generation techniques.

DOI: 10.1002/anie.202113082

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202113082