Oxygen‐Fate Accounting in GaN‐Derived Solar Water Conversion

Solar water splitting should be evaluated by its oxygen‐side products as well as hydrogen evolution. GaN/InGaN systems provide established examples of overall water splitting, while H ₂ /H ₂ O ₂ coproduction, accompanied by O ₂ formation, has been reported for Pd‐modified GaN nanowires in alkaline seawater. We examine how light absorption, charge transport, and local heating in GaN‐derived structures affect oxygen‐product formation and peroxide stability. Full‐spectrum utilization is assessed through the distinct contributions of carriers and heat. This Perspective connects hydrogen production with oxygen‐product identification, oxygen‐source tracing, and peroxide stability. Product balances and measurements of carrier and thermal effects provide a basis for evaluating GaN‐derived material design.