Highly enhanced and stable activity of defect-induced titania nanoparticles for solar light-driven CO₂ reduction into CH₄

Photocatalytic reduction of CO₂ to fuel offers an exciting opportunity for helping to solve current energy and global warming problems. Although a number of solar active catalysts have been reported, most of them suffer from low product yield, instability, and low quantum efficiency. Therefore, the design and fabrication of highly active photocatalysts remains an unmet challenge. In the current work we utilize hydrogen-doped, blue-colored reduced titania for photocatalytic conversion of CO₂ into methane (CH₄). The photocatalyst is obtained by exposure of TiO₂ to NaBH₄ at 350 °C for 0.5 h. Sensitized with Pt nanoparticles, the material promotes solar spectrum photoconversion of CO₂ to CH₄ with an apparent quantum yield of 12.40% and a time normalized CH₄ generation rate of 80.35 μmol g⁻¹ h⁻¹, which to the best of our knowledge is a record for photocatalytic-based CO₂ reduction. The material appears intrinsically stable, with no loss in sample performance over five 6 h cycles, with the sample heated in vacuum after each cycle.