Electron configurations and conductivity are significant descriptors/characteristics for the oxygen evolution reaction (OER), which can be modulated with heteroatom doping. Given that metal substitution usually reduces the number of active sites of spinel electrocatalysts, the effect of anion doping on the electronic structure has been investigated by using ZnCo2O4 (ZCO) as a demonstration. Compared with Co3+-dominated ZCO, the substitution of oxygen with less electronegative sulfur raises the portion of Co2+ in the low-spin states (t2g6eg1), which is more OER-active than Co3+ (t2g6eg0). Co2+ ...