Dan Zhu#, Lingxing Zan#,*, Yunchuan Tu*, Wenlin Zhang, Hongling Zhang, Yuxin Luo, Lu Liu, Jiawen Zheng, Qiang Weng, Qingbo Wei, Di Li, Xin Bo*, Chuan Zhao*, Feng Fu, Science China Chemistry, 2025, 68

The apparent OER activity on S-incorporated catalyst outputs an over-estimated current, which is actually contributed not only from the oxygen evolution reaction (OER), but also from the inevitable surface reconstruction-involved electrochemical oxidation reactions. The mechanism on the such catalyst still stays complex and controversial. Here, we applied a set of operando electrochemical-spectrometric methodologies to investigate the precise interfacial activation process on the bimetallic sulfide heterogeneous catalyst, which delivers an extraordinary OER activity of 100 mA cm^-2 at 190 mV overpotential. Differential electrochemical mass spectrometry (DEMS) suggested the electrochemical oxidations of the lattice S to SO, SO₂ and SO₄^2- species and the coordinately unsaturated metal sites. Operando Raman and attenuated total reflectance surface-enhanced infrared absorption spectra confirmed the phase transformation of sulfide to oxide, and then to oxyhydroxide, which acted as active site for OER. The density functional theory also simulated this process that the (CoNi)_xS_y transition-phase exhibited the optimal activity, and elucidated the attenuation kinetics of the apparent activity upon OER. This study demonstrates the structure evolution of the certain S-incorporated catalyst and establishes the protocol for the real activity identification under the real-time reaction.

First Authors: Zhu Dan, Master’s student, Yan’an University; A/Prof. Zan Lingxing, Yan’an University

Correspondence Authors: Dr. Tu Yunchuan, Chongqing University; A/Prof. Bo Xin, Shaanxi Normal University; Prof. Zhao Chuan, University of New South Wales

Full Text Link: https://www.sciengine.com/SCC/doi/10.1007/s11426-024-2622-4