TiO2 Photonic Crystals with Localized Surface Photothermal Effect and Enhanced Photocatalytic CO2 Reduction Activity

Photothermal effect through absorbing infrared light is an important strategy for various living beings to regulate their body temperature. Although utilization of this effect in modern human technologies such as photoconversion and catalysis is important, it is still in its infancy for the scientific research. Herein, we design and prepare TiO2 photonic crystals (TiO2 PCs) through a template-free anodization-calcination method for photocatalytic solar fuel production. Encouragingly, a slow photon effect was substantiated, contributing to enhanced light utilization ability. More importantly, we present the localized surface photothermal effect and explain how this heat arising from TiO2 PCs can be harnessed for photocatalytic reaction. Owing to its extraordinary physicochemical property and effective light utilization, photocatalytic CH4 production performance of TiO2 PCs is greater than that of commercial TiO2 and TiO2 nanotube arrays. Such a photothermal effect deriving from unique photonic crystal structure has great potential in photoconversion application.