Unbiased Photoelectrochemical H2O2 Coupled to H2 Production via Dual Sb2S3-Based Photoelectrodes with Ultralow Onset Potential

The productions of hydrogen peroxide (H2O2) and hydrogen (H-2) in a photoelectrochemical (PEC) water splitting cell suffer from an onset potential that limits solar conversion efficiencies. Moreover, the formation of H2O2 through two-electron PEC water oxidation reaction competes with four-electron oxidation evolution reaction. Herein, we developed the surface selenium doped antimony trisulfide photoelectrode with the integrated ruthenium cocatalyst (Ru/Sb-2(S,Se)(3)) to achieve the low onset potential and high Faraday efficiency (FE) for selective H2O2 production. The photoanode exhibits an outstanding average FE of 85 % in the potential range of 0.4-1.6 V-RHE and the H2O2 yield of 1.01 mu mol cm(-2) min(-1) at 1.6 V-RHE, especially at low potentials of 0.1-0.55 V-RHE with 80.4 % FE. Impressively, an unassisted PEC system that employs light and electrolyte was constructed to simultaneously produce H2O2 and H-2 production on both the Ru/Sb-2(S,Se)(3) photoanode and the Pt/TiO2/Sb2S3 photocathode. The integrated system enables the average PEC H2O2 production rate of 0.637 mu mol cm(-2) min(-1) without applying any addition bias. To our knowledge, this is the first demonstration that Sb2S3-based photoelectrodes exhibit H2O2/H-2 two-side production with a strict key factor of the system, which represents its powerful platform to achieve high efficiency and productivity and the feasibility to facilitate value-added products in neutral conditions.