Transformation of CuOx/TiO2 Photocatalysts During CO2 Reduction

Photocatalytic processes utilizing the energy of light quanta to synthesize valuable compounds are studied quite widely, but particular attention is paid to the development of effective and stable photocatalysts. The present study considers the transformation of photocatalysts based on TiO₂ modified with copper and its oxide compounds (CuO_x) in the conditions of CO₂ reduction under the LED irradiation (397 nm). The influence of TiO₂ precalcination on the state of the copper cocatalyst is demonstrated. It is shown by in situ X-ray absorption (XANES) that modifying the calcined TiO₂ photocatalyst with copper results in higher content of (0) and (1+) copper sates than in the case of the non-calcined photocatalyst. It is established that the fraction of metal copper in both photocatalysts increases during the reaction due to the accumulation of photogenerated electrons on the copper cocatalyst.