Dual-channel synthesis of H 2 O 2 via photoelectrocatalytic water oxidation and oxygen reduction over a TaON/Ta 3 N 5 /CuI/Cu foam electrode

A novel type-II heterojunction TaON/Ta 3 N 5 /CuI powder is loaded on the surface of the Cu foam by electrophoresis assisted one-step calcination, which is used for the synthesis of H 2 O 2 by photoelectrocatalysis (PEC). At an applied potential of 1.23 V vs. NHE, the yield of H 2 O 2 on the TaON/Ta 3 N 5 /CuI/Cu electrode is 193.0 μmol L −1 under a saturated O 2 atmosphere. The solar-to-chemical conversion efficiency (SCC) and apparent quantum efficiency (AQE) of the TaON/Ta 3 N 5 /CuI/Cu electrode are 0.09% and 21.6%, respectively. As the dominant radicals, electrons and holes are involved in the PEC synthesis of H 2 O 2 , whose pathways include a two-electron and a four-electron water oxidation reaction (WOR) and a two-electron oxygen reduction reaction (ORR).