Synthesis of Pd7P3/CdS with high hydrogen production activity in water splitting and enhancement mechanism under visible light radiation

Abstract

Abstract We report a new Pd7P3 cocatalyst that significantly enhances H2 production performance and durability for water splitting under visible light radiation (λ ≥ 450). The 3 wt% Pd7P3/CdS compared with pure CdS had a 30-fold larger H2 production amount (302860 vs. 10126 μmol/g) and 39-fold larger average H2 production rate (41645 vs. 1066 μmol/g/h) after 10 h of visible light radiation. The 3 wt% Pd7P3/CdS had an apparent quantum yield of 35.1% after 72 h. The lifespan and reuse cycle tests on the 3 wt% Pd7P3/CdS showed that addition of Pd7P3 into CdS enhanced H2 production ability and reusability in photocatalytic water splitting. The photoluminescence and photocurrent tests showed the Pd7P3 cocatalyst extracted photoelectrons from the CdS bulk under visible light radiation, then those photoelectrons migrated to the Pd7P3/CdS interfaces and reacted with the H+ adsorbed on the catalyst surface, producing abundant H2. Therefore, the addition of Pd7P3 improves the movement of photoelectrons, separation of photo-generated electron-hole pairs, and photoelectron utilization efficiency, thus significantly enhancing the photocatalytic H2 production ability.