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

Abstract: 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 0.5h. 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 80.35µmolg-1h-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 6h cycles, with the sample heated in vacuum after each cycle.