Ru single atoms regulate electron distribution in defective NiFe LDH for enhanced oxygen evolution reaction
Xiaolin Hu, Chengbin Cai, Yuru Wang, Shiyue Zhang, Xiaolong Guo, Haozhi Wang, Yida Deng
Abstract
Supported single-atom catalysts (SACs) demonstrate exceptional catalytic performance, atom efficiency and selectivity, as a result, they are the potential candidates used in oxygen evolution reaction (OER). However, stabilizing monodispersed noble-metal atoms is challenging. This is especially true for two-dimensional (2D) layered double hydroxide (LDH) nanostructures. Here, we report the successful stabilization of ruthenium (Ru) single atoms (SAs). These SAs are located within a defective NiFe LDH nanosheet. This material is named Ru SAs/D-NiFe LDH@NF and formed through the hydrothermal reaction followed by etching. The resulting catalyst exhibits outstanding OER performance in alkaline media, achieving an exceedingly low overpotential (206 mV) at 50 mA cm<sup>-2</sup>, which remarkably decreases relative to the overpotential in pristine NiFe LDH (311 mV). Ru SAs regulate the electron distribution near defects, optimizing the Ru-NiFe hydroxide interaction and diminishing energy barrier for forming *OOH intermediates, as revealed by density functional theory (DFT) calculations. Moreover, the catalyst demonstrates remarkable stability in Zn-air batteries (ZABs), delivering the maximal power density (170 mW cm<sup>-2</sup>). Furthermore, it maintains stable operation for 350 hours, highlighting its practical viability. This work provides a versatile strategy for integrating single-atom sites into NiFe LDH, paving the way for the design of next-generation SACs for energy conversion applications.