Zhang Bing, Du Ziping, Sun Ruoxin, Lai Xinyue, Lan Jieyi, Liu Xijun, Yan Liang
School of Chemistry and Materials Engineering, Huizhou University, Huizhou 516007, China.
School of Intelligent Manufacturing Huzhou College, Huzhou 313000, China.
ACS Appl Mater Interfaces. 2022 Oct 26;14(42):47529-47541. doi: 10.1021/acsami.2c10482. Epub 2022 Oct 14.
Electronic modulation via heterostructures or vacancies has been recently regarded as an effective strategy to improve electrocatalytic activity by optimizing the adsorption free energies of hydrogen evolution reaction (HER) or oxygen evolution reaction (OER) active intermediates during the reaction. Herein, tremella-like Ni-NiO with O-vacancy heterostructure nanosheets grown in situ on TiCT MXenes (Ni-NiO/TiCT MXene) are fabricated via a facile strategy. Benefitting from the heterointerfaces between Ni and NiO, the synergetic coupling effects of MXenes and Ni-NiO heterostructures, the O-vacancies, and the unique architecture, the as-prepared Ni-NiO/TiCT MXene showed superior activity toward the HER and OER in alkaline electrolyte, only requiring overpotentials of 72 mV for the HER and 248 mV for the OER to offer 10 mA cm. Density functional theory (DFT) calculations revealed that Ni-NiO with O-vacancies can effectively increase the electron density around the Fermi level and modulate the Gibbs free energies of the intermediates during catalytic reactions, thus accelerating the reaction kinetics.
通过异质结构或空位进行电子调制最近被认为是一种有效的策略，可通过优化析氢反应（HER）或析氧反应（OER）活性中间体在反应过程中的吸附自由能来提高电催化活性。在此，通过一种简便的策略制备了原位生长在TiCT MXene上的具有O空位异质结构纳米片的银耳状Ni-NiO（Ni-NiO/TiCT MXene）。得益于Ni和NiO之间的异质界面、MXene与Ni-NiO异质结构的协同耦合效应、O空位以及独特的结构，所制备的Ni-NiO/TiCT MXene在碱性电解质中对HER和OER表现出优异的活性，HER仅需72 mV的过电位，OER仅需248 mV的过电位即可提供10 mA cm。密度泛函理论（DFT）计算表明，具有O空位的Ni-NiO可以有效地增加费米能级周围的电子密度，并在催化反应过程中调节中间体的吉布斯自由能，从而加速反应动力学。
