PdO/LaCoO3 heterojunction photocatalysts for highly hydrogen production from formaldehyde aqueous solution under visible light

• Rapid preparation of PdO/LaCoO3 heterojunction photocatalyst.
• Absolute investigation of PdO/LaCoO3 photocatalyst for H2 production from formaldehyde.
• An enhanced visible light photocatalytic activity by heterojunction.

PdO/LaCoO3 heterojunction photocatalyst was prepared by sol gel process and deposition precipitation method under mild condition, used for H2 production from formaldehyde aqueous solution without any additives at low temperature. We demonstrate through PdO doping that creation of heterojunction on LaCoO3 particles surface can effectively adjust band-gap and Fermi energy levels to apply in hydrogen production from formaldehyde solution under visible light. The work indicate that the heterojunction structure can greatly enhance the charge generation, largely improve the visible light absorptive quality and effectively restrain the recombination of photogenerated electron–holes pairs to exhibit a higher photocatalytic activity. The optimal photocatalytic activity of PdO/LaCoO3 in H2 production from formaldehyde solution under visible light was ten times of LaCoO3 (1.26 mmol h−1 g−1). The photocatalysts composition and optical properties were characterized by XRD, TEM, EDS, XPS, TPR-H2, UV–vis (DRS) and Photoluminescence (PL).