CO2 photoreduction to methanol over Nb and N co-doped TiO2 aerogel deposited CuxO

Abstract

Global warming is primarily caused by greenhouse gases such as CO2. One smart solution to mitigate its impact is to convert CO2 into hydrocarbons through photoreduction processes. In this work, CO2 was photo-catalytically reduced over new aerogel-based materials to produce methanol, using a solar simulator and a specifically designed photoreactor.Cu-loaded Nb and N co-doped TiO2 aerogels (Cu/ATiO2: Nb, N) were synthesized by the sol-gel method followed by supercritical CO2 drying and annealing in a controlled atmosphere. The obtained photocatalysts benefit from the peculiar properties of aerogels with high specific surface area (88 m2/g) and porosity. N and Nb doping improved the electronic and optical properties, resulting in a significantly improved visible light absorption compared to pure TiO2 aerogel (ATiO2) or commercial catalyst P25. CuxO nanoparticles, smaller than 5 nm and uniformly distributed on the surface of aerogels, contribute to the improvement of the conversion efficiency. Used for CO2 photoreduction, one of the best-reported methanol yields (1.69 ± 0.05 mmol/gcat/h) was obtained, and the impact of Cu, Nb, and N on methanol production was studied.

Keywords

• Nb and N co-doped TiO2
• CO2 photoreduction
• Methanol
• CuxO
• Aerogel