Ruthenium oxide (RuO2) shows some of the best performance as an OER material in acidic environments.
Zinc oxide | Calcium oxide | Ruthenium | Nitrous oxide | Tin oxide | nitrogen oxide | Titanium oxide | Magnesium oxide | Sulfur oxide | Silver-oxide battery | Silicon oxide | Ruthenium oxide | poly(1,4-phenylene oxide) | Nitrous oxide engine | Nitrogen oxide | magnesium oxide | Iron oxide | Exhaled nitric oxide | Cobalt oxide | calcium oxide |