Platinum Nanoparticles Supported on TiO₂ Photonic Crystals as Highly Active Photocatalyst for the Reduction of CO₂ in the Presence of Water

Abstract

Abstract Photonic crystals can delay the propagation of light and increase its path length through a slow‐light effect, which could have immense potential in improving photocatalytic conversion efficiencies. We employed a colloidal crystal template method to synthesize TiO 2 photonic crystals (PC‐TiO 2 ), with platinum nanoparticles (Pt NPs) being deposited on the surface of the PC‐TiO 2 support at different loading amounts by the gas bubbling‐assisted membrane reduction (GBMR) method. A series of Pt/PC‐TiO 2 photocatalysts with well‐defined inverse‐opal structure have uniform Pt NPs (about 2.5 nm) homogeneously dispersed on the pore walls of the support. The slow‐light effect of photonic crystals effectively enhances the absorption efficiency of solar irradiation. Moreover, the Pt deposition significantly extends the spectral response and reduces the recombination rates of photoinduced electron–hole pairs. As a result, the Pt x /PC‐TiO 2 catalysts exhibit excellent photocatalytic activity for the reduction of CO 2 in the presence of H 2 O. In addition, we propose a reaction mechanism for the photoreduction of CO 2 under light irradiation.