“…142 Nowadays, advanced studies on trimetallic and further multimetal materials for OER catalysis have been highly promising. Therefore, a variety of trimetallic metal materials such as FeCoNi alloys, 145 FeCoNiO x , 144,146,147 NiFeWO x , 33,[148][149][150][151][152] FeCoNi phosphides, 153 Cr-doped FeCoNiO x , 154 NiFeMoO x , 155 NiFeBaO x , 156 NiFeMg oxyhydroxide, 157 FeNiCr hydroxide 158 and alloy, 159 MnFeNi hydroxide 157 and alloy, 160 NiCoV boride, 161 and NiFeMoB alloy 162 have been developed as OER catalysts. Moreover, HECs are a type of catalyst materials composed of four or more metals and have a high degree of configurational entropy.…”