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

• Published in: Solar energy materials and solar cells 2019-06, Vol.194, p.195-206
• Main Authors: Bera, Susmita, Ghosh, Srabanti, Shyamal, Sanjib, Bhattacharya, Chinmoy, Basu, Rajendra N.
• Format: Article
• Language: English
• Subjects: BiFeO3; Bismuth compounds; Carrier density; Catalysis; Catalysts; Charge transfer; Current carriers; Design modifications; Electromagnetic absorption; Electron transfer; Energy levels; Fossil fuels; Gold; H2 generation; Heterojunctions; Heterostructures; Hydrogen; Hydrogen production; Irradiation; Light irradiation; Nanoparticles; Noble metals; Nyquist plots; Oxides; Perovskites; Photocatalysis; Photocatalysts; Photoelectric effect; Photoelectric emission; Photoelectrochemical properties; Plasmonic Au nanoparticles; Radiation; Radiolysis; Synthesis; Visible light photocatalyst; Water splitting
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2019.01.042

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 (λ > 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 ∼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 × 1017 cm−3) compared to pure BFO (0.47 × 1017 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. [Display omitted] •Au/BiFeO3 heterostructures are developed by hydrothermal method followed by radiolysis.•Au/BiFeO3 shows morphology and pH dependent photocatalytic hydrogen generation.•Au/BiFeO3 demonstrates enhanced photoelectrochemical properties under visible light.•Enhanced charge separation due to intimate interfacial contacts between Au NPs and BiFeO3 nanosheets which enhances catalytic activity.