Enhancing TiO2 activity for CO2 photoreduction through MgO decoration

Herein we report on the influence of MgO's basic character in the photoactivity of MgO:TiO2 nanocomposites for the CO2 reduction reaction. TiO2 nanoparticles, decorated with MgO in different mass proportions, were synthesized by the physical mixing of pre-synthesized oxides followed by calcination. The decorated samples presented enhanced photocatalytic activity with higher selectivity for CO, while CH4 was also produced, as well as HCOOH and CH3COOH in a liquid medium in lower proportions. The results indicate that the beneficial MgO influence is only effective at low amounts, whilst a high MgO amount favors an insulating behavior instead of semiconducting, reducing the nanocomposite performance for CO2 photoreduction.