“…[9][10][11][12] To date, noble-metal-based materials (e.g., RuO 2 and IrO 2 ) are still considered as being the most efficient electrocatalysts for the OER, but the highcost and scarcity make them not the most economically viable options. [13][14][15][16][17] Therefore, it is of significant importance to develop low-cost, earth-abundant, and yet efficient alternatives for the OER.A myriad of alternative OER catalysts based on earth-abundant cobalt (Co), including alloys, [18][19][20][21][22] oxides, [23][24][25][26][27] sulfides, [28][29][30][31][32] borates, [33,34] phosphates, [35][36][37][38][39][40] and nitrides, [41][42][43][44] have been widely researched. Among them, the Mott-Schottky hybrids by integrating metal and semiconductor have attracted more attention recently, such as Co/CoN x , [45,46] Co/ CoP x , [47,48] and Co/CoO x , [49,50] owing to the existence of strong coupled interface between different components.…”