Liu Caichi, Han Yu, Yao Libing, Liang Limin, He Jiayin, Hao Qiuyan, Zhang Jun, Li Ying, Liu Hui
School of Material Science and Engineering, Hebei University of Technology, Tianjin, 300130, P. R. China.
SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing, 210096, China.
Small. 2021 Feb;17(7):e2007334. doi: 10.1002/smll.202007334. Epub 2021 Jan 27.
Developing cost-effective and high-efficiency electrocatalysts toward alkaline oxygen evolution reaction (OER) is crucial for water splitting. Amorphous bimetallic NiFe-based (oxy)hydroxides have excellent OER activity under alkaline media, but their poorly electrical conductivity impedes the further improvement of their catalytic performance. Herein, a bimetallic NiFe-based heterostructure electrocatalyst that is composed of amorphous NiFe(OH) and crystalline pyrite (Ni, Fe)Se nanosheet arrays is designed and constructed. The catalyst exhibits an outstanding OER performance, only requiring low overpotentials of 180, 220, and 230 mV at the current density of 10, 100, and 300 mA cm and a low Tafel slope of 42 mV dec in 1 m KOH, which is among the state-of-the-art OER catalysts. Based on the experimental and theoretical results, the electronic coupling at the interface that leads to the increased electrical conductivity and the optimized adsorption free energies of the oxygen-contained intermediates plays a crucial role in enhancing the OER activities. This work focusing on improving the OER performance via engineering amorphous-crystalline bimetallic heterostructure may provide some inspiration for reasonably designing advanced electrocatalysts.
开发具有成本效益和高效率的用于碱性析氧反应（OER）的电催化剂对于水分解至关重要。非晶态双金属镍铁基（羟基）氧化物在碱性介质下具有出色的OER活性，但其较差的导电性阻碍了其催化性能的进一步提高。在此，设计并构建了一种由非晶态NiFe(OH)和结晶黄铁矿（Ni, Fe）Se纳米片阵列组成的双金属镍铁基异质结构电催化剂。该催化剂表现出优异的OER性能，在1 M KOH中，在电流密度为10、100和300 mA cm时仅需要180、220和230 mV的低过电位以及42 mV dec的低塔菲尔斜率，这属于最先进的OER催化剂之列。基于实验和理论结果，界面处的电子耦合导致电导率增加以及含氧中间体的吸附自由能优化，这在提高OER活性方面起着关键作用。这项通过构建非晶-结晶双金属异质结构来提高OER性能的工作可能为合理设计先进电催化剂提供一些启发。
