Bi-doped Ceria with Increased Oxygen Vacancy for Enhanced CO2 Photoreduction Performance

Oxygen vacancy plays an important role in promoting CO2 adsorption and reduction on photocatalysts. Bi was heavily doped into ceria, forming a solid solution catalyst Ce1-xBixO2-δ meanwhile maintaining the fluorite structure, to increase the oxygen vacancy concentration. The sample Ce0.6Bi0.4O2-δ showed the highest photocatalytic activity with a CO yield of ～4.6 times that of the pristine ceria nanorods. Bi was homogeneously dispersed into the fluorite ceria which was confirmed by XRD and EDX elemental mapping. It has been evidenced by the results of Raman and XPS that Bi introduction boosts the concentration of oxygen vacancy in the solid solution that can facilitate the adsorption/activation of carbonate and bicarbonate intermediates on its surface according to in-situ FT-IR.