Experimental evaluation of the activity and selectivity of pure MnWO4 and doped with rare earth ions in the CO2 photoreduction process.

Abstract

The reduction of CO2 to produce useful carbon compounds offers a way to manage the emissions from various industrial sectors. However, selecting efficient systems remain a crucial issue, especially considering the low selectivity of the photocatalysts traditionally used in CO2 photoreduction processes. Here we demonstrate that the modification of MnWO4 with rare earth ions (Europium and Terbium) synthesized by the coprecipitation method can tune the activity and selectivity of the products formed in the process of CO2 photoreduction under UV irradiation. The CO2 photoreduction assays indicated that the photocatalysts presented good activity, resulting in acetate, acetone, acetic acid, ethanol, methane, and methanol products. Doping provided selectivity near 100% for CO2 conversion to methanol and increased the capacity of C2 (e.g., ethanol) production, opening the way for a better understanding of the activity and selectivity of tungstates in the CO2 photoreduction process.