Porous Carbon Aerogel Decorated with TiO2 Quantum Dots for Highly Improved Photocatalytic H2 Evolution

Abstract

The design of photocatalysts plays a central role in determining the photocatalytic H2 yield. Here, we used a design strategy that is different from conventional methods to prepare our photocatalytic systems. Large porous carbon aerogels (CA) with rich surface areas were used to receive photogenerated electrons. TiO2 quantum dots were used as photocatalysts and anchored on large porous CAs to form CA@TiO2 systems. The H2 yield of the optimized CA@TiO2 composite is ∼2.1 mmol/g, ∼11 times higher than that of pure TiO2 quantum dots. High-resolution X-ray photoelectron spectroscopy and high-angle annular dark-field scanning transmission electron microscopy demonstrate that the photogenerated electrons can be easily transferred from TiO2 quantum dots to porous CAs. Thus, efficient charge separation can be realized for the succeeding highly efficient H2 evolution. Our results here provide a different way from conventional methods to design photocatalytic systems with high H2 yield.