Preparation of CoSOH/Co(OH)₂ composite nanosheets and its catalytic performance for oxygen evolution

Zn-Co(OH)₂ precursor was hydrothermally deposited on carbon paper at 120 ℃, using cobalt nitrate and zinc nitrate as raw materials. Then Zn-Co(OH)₂ was etched and partially sulfided into CoSOH/Co(OH)₂ with 5 mol/L NaOH and 1 mol/L Na₂S aqueous solution at room temperature. The catalytic performance in oxygen evolution reaction (OER) was investigated. XRD, SEM, TEM, XPS were used to characterize the microstructure, physical and chemical properties of the catalyst. The results show that the used method can etch Zn atoms, create oxygen vacancies and dope sulfur. The oxygen vacancies and doped sulfur play a positive role in enhancing the OER performance. In addition, amorphous CoSOH also exhibited better OER activity. The synergy between CoSOH and Co(OH)₂ finally induces the best catalytic properties (overpotential η=310 mV, Tafel slope b=90 mV/dec) and long-term electrochemical stability, that is CoSOH/Co(OH)₂ possess superior electrocatalytic oxygen evolution performance.