Transition metal-based sulfide catalysts for electrocatalytic oxygen evolution have been reported, but such sulfide catalysts are not stable under the condition of high overpotential and strong alkalinity used for oxygen evolution reaction. Herein, a series of vulcanized Co₃O₄ nanocubes with different vulcanization degree were synthesized. The optimized electrocatalyst delivered a lower overpotential of 314 mV at 10 mA cm^-2 with a small Tafel slope of 67.4 mV dec^-1 in 1 M KOH. The catalyst after long time of OER operation was then characterized and compared with the pristine catalyst. It was found that the precatalyst experienced in situ phase evolution with the generation of CoOOH species. On the catalytic electrode, the catalytic layer should be composed of vulcanized CoS_x/ S-doped CoOOH that acts as catalytic active phase. This study provides new information for the sulfide electrocatalysts and is conducive to the design of advanced oxygen evolution catalysts.

已经报道了用于电催化氧释放的基于过渡金属的硫化物催化剂，但是这种硫化物催化剂在用于氧释放反应的高过电势和强碱度的条件下是不稳定的。本文合成了一系列不同硫化度的硫化Co ₃ O ₄纳米立方体。经过优化的电催化剂在1 mA KOH中的10 mA cm ^-2时具有较低的314 mV过电势，而Tafel斜率较小，为67.4 mV dec ^-1。然后对经过长时间OER操作的催化剂进行表征，并将其与原始催化剂进行比较。发现该预催化剂在原位经历CoOOH物种产生的阶段演化。在催化电极上，催化层应由硫化的CoS _x / S掺杂的CoOOH组成，其起催化活性相的作用。该研究为硫化物电催化剂提供了新的信息，有利于先进的析氧催化剂的设计。