Abstract
Developing high-efficiency photoelectrodes plays an important role in the photoelectrocatalytic generation of hydrogen peroxide (H(2)O(2)) in the photoelectrochemical (PEC) water splitting field. In this work, an innovative strategy was proposed, the synergistic photocatalytic production of H(2)O(2) using a bidirectional photoanode-photocathode coupling system under visible-light irradiation. Fe(2)O(3)-Ti, as the photoanode, which was built by way of Fe(2)O(3) loaded on Ti-mesh using the hydrothermal-calcination method, was investigated in terms of the suitability of its properties for PEC H(2)O(2) 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 Fe(2)O(3)-Ti photoanode and a WO(3)@Co(2)SnO(4) photocathode was established for the bidirectional synergistic production of H(2)O(2) under visible-light irradiation. The yield of H(2)O(2) reached 919.56 μmol·L(-1)·h(-1) in 2 h over -0.7 V with 1 mol·L(-1) of KHCO(3) as the anolyte and 0.1 mol·L(-1) Na(2)SO(4) as the catholyte (pH = 3). It was inferred that H(2)O(2) production on the WO(3)@Co(2)SnO(4) photocathode was in line with the 2e(-) oxygen reduction reaction (ORR) principle, and on the Fe(2)O(3)-Ti photoanode was in line with the 2e(-) water oxidation reaction (WOR) rule, or it was indirectly promoted by the electrolyte solution KHCO(3). This work provides an innovative idea and a reference for anode-cathode double coupling systems for the bidirectional production of H(2)O(2).