Photocatalytic hydrogen generation using gold decorated BiFeO3 heterostructures as an efficient catalyst under visible light irradiation

Perovskites based oxides materials with a suitable energy level have been considered as efficient photocatalysts for solar hydrogen generation. Gold nanoparticles (Au NPs)-sensitized BiFeO3 (BFO) perovskite heterostructures was synthesized, characterized and tested for hydrogen generation under visible light (lambda > 420 nm) irradiation. Au/BFO heterostructures was synthesized using a facile hydrothermal method followed by radiolysis without using any surfactant or strong reducing agent. The shape-dependent photocatalysis revealed that the BFO octahedron (BFO-Oct) exhibited higher hydrogen generation (1.4 mmol h(-1) g(-1)) than the BFO nanosheets (BFO-Ns) (1.1 mmol h(-1) g(-1)) and BFO cylindrical shaped (BFO-Cyl) (0.5 mmol h(-1) g(-1)). After radiolytic construction of the Au/BFO heterostructure, more efficient hydrogen generation was obtained due to the photoinduced electron transfer. The photoresponse of the Au/BFO heterostructures was also assessed in terms of the photocurrent via photoelectrochemical (PEC) measurement which showed Au/BFO-Ns generated higher photocurrents than BFO-Ns by a factor of similar to 3.8. The Nyquist plot demonstrated facile charge transfer of BFO-Ns after formation of heterojunction with Au NPs. The Mott-Schottky plot revealed that catalysts are n-type and photo generated charge carrier concentration has been increased for Au/BFO heterostructures (0.92 x 10(17) cm(-3)) compared to pure BFO (0.47 x 10(17) cm(-3)). On the basis of experimental results, the enhanced photocatalytic activities of Au/BFO heterostructures could be ascribed to the significant visible light absorption and the efficient charge carrier separation. This study offers a new route to design noble metal modified perovskites based heterostructure as photocatalysts for water splitting.