Enhancement of CO₂ photoreduction efficiency by supporting blue TiO₂ with photonic crystal substrate

The catalytic performance of TiO₂ in photoreduction of CO₂ is limited by its weak absorption in the visible range. In this work, a photonic crystal supported blue TiO₂ photocatalyst (BTPC) was prepared to demonstrate a 5–6 times higher activity and improved CH₄ selectivity compared to the BT catalysts deposited on quartz plate. By investigating the influence of the reflection intensity and wavelength of PC support, the superior catalytic performance was found to be originated from the enhanced light absorption of BT and the increased surface electron density brought by the PC support. Based on the study of BT loading on support, multilayer BTPC catalyst was designed to take the most advantage of the transmitted light and achieve a higher conversion of CO₂ in the unit area of irradiation.