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

The photonic crystal could delay the propagation of light and increase its path length through slow-light effect, which has an immense potential in improving photocatalytic conversion efficiency. In the present work, photonic crystal TiO2 (PC-TiO2) was fabricated by colloidal crystal template method, and platinum nanoparticles (Pt NPs) with different contents were deposited on the surface of PC-TiO2 carrier by the gas bubbling-assisted membrane reduction (GBMR) method. A series of Pt/PC-TiO2 photocatalysts possess well-defined inverse opals structure, and Pt NPs with uniform sizes (about 2.5 nm) homogeneously dispersed on the inner wall of carriers. The slow-light effect of photonic crystal effectively enhanced the absorption efficiency of solar irradiation. Pt deposition significantly extended the spectral response and reduced the recombination rates of photoinduced electron-hole pairs. Therefore, they exhibited superior photocatalytic activity for the reduction of CO2 with H2O. And the reaction mechanism of the CO2 photoreduction under light irradiation was proposed.