Copper based TiO2 honeycomb monoliths for CO2 photoreduction

Abstract

The direct photoreduction of CO₂via catalytic conversion of copper supported on TiO₂ based monolithic structures is a means by which solar fuels can be produced. Copper based monolithic structures with varying loadings were synthesized through a sol–gel dip coating procedure and tested for CO₂ reduction with H₂O as a reductant in the gaseous phase. Results established that increased copper concentration can decrease crystalline size and promote anatase to rutile phase transformation. The coated monolithic structures were dominated by mainly Cu¹⁺ species, as confirmed by XPS while bulk characterization suggests that these species are present in the crystal lattice via substitution of Ti⁴⁺ ions with Cu¹⁺ ions. The catalytic performance of the Cu doped TiO₂ monoliths for hydrocarbon formation was found to be considerably higher when compared to pure TiO₂ under UVA or visible light irradiation.