Designing FeO-Ti as Photoanode in H-Type Double-Electrode Coupling Systems for Bidirectional Photocatalytic Production of HO.

Developing high-efficiency photoelectrodes plays an important role in the photoelectrocatalytic generation of hydrogen peroxide (HO) in the photoelectrochemical (PEC) water splitting field. In this work, an innovative strategy was proposed, the synergistic photocatalytic production of HO using a bidirectional photoanode-photocathode coupling system under visible-light irradiation. FeO-Ti, as the photoanode, which was built by way of FeO loaded on Ti-mesh using the hydrothermal-calcination method, was investigated in terms of the suitability of its properties for PEC HO production after optimization of the bias voltage, the type of electrolyte solution, and the concentration of the electrolyte. Afterwards, a H-type double-electrode coupling system with an FeO-Ti photoanode and a WO@CoSnO photocathode was established for the bidirectional synergistic production of HO under visible-light irradiation. The yield of HO reached 919.56 μmol·L·h in 2 h over -0.7 V with 1 mol·L of KHCO as the anolyte and 0.1 mol·L NaSO as the catholyte (pH = 3). It was inferred that HO production on the WO@CoSnO photocathode was in line with the 2e oxygen reduction reaction (ORR) principle, and on the FeO-Ti photoanode was in line with the 2e water oxidation reaction (WOR) rule, or it was indirectly promoted by the electrolyte solution KHCO. This work provides an innovative idea and a reference for anode-cathode double coupling systems for the bidirectional production of HO.