Benchmarking commercial RuO2 for acidic water oxidation

Commercial ruthenium oxide is commonly used as a benchmark for evaluating the activity of acidic water oxidation catalysts (WOCs). However, the performance of different commercial RuO2 (c-RuO2) varies greatly in the different literatures. Inconsistent standards are detrimental to the development of WOCs. Herein, we compared the acidic water oxidation performance of c-RuO2 from different suppliers under identical testing conditions. The results indicate that the c-RuO2 can be classified into two types according to their catalytic performance, the low η10 (overpotential at 10 mA/cm2) type and the high η10 type. The low η10 can be as low as ∼170 mV and the high η10 is around 240 mV. The c-RuO2 with low η10 are crystalline-amorphous while the high η10 commercial RuO2 are crystalline. This study provides a comprehensive benchmark for evaluating the performance of acidic WOCs.