Selective photocatalytic reduction of CO(2) to methanol in CuO-loaded NaTaO(3) nanocubes in isopropanol

A series of NaTaO(3) photocatalysts were prepared with Ta(2)O(5) and NaOH via a hydrothermal method. CuO was loaded onto the surface of NaTaO(3) as a cocatalyst by successive impregnation and calcination. The obtained photocatalysts were characterized by XRD, SEM, UV–vis, EDS and XPS and used to photocatalytically reduce CO(2) in isopropanol. This worked to both absorb CO(2) and as a sacrificial reagent to harvest CO(2) and donate electrons. Methanol and acetone were generated as the reduction product of CO(2) and the oxidation product of isopropanol, respectively. NaTaO(3) nanocubes loaded with 2 wt % CuO and synthesized in 2 mol/L NaOH solution showed the best activity. The methanol and acetone yields were 137.48 μmol/(g·h) and 335.93 μmol/(g·h), respectively, after 6 h of irradiation. Such high activity could be attributed to the good crystallinity, morphology and proper amount of CuO loading, which functioned as reductive sites for selective formation of methanol. The reaction mechanism was also proposed and explained by band theory.