Visible Light Active Ce-Doped and Cu–Ce co-doped TiO<sub>2</sub> Nanocrystals and Optofluidics for Clean Alcohol Production from CO<sub>2</sub>
Andrea Diego-Rucabado, Ivan Merino‐Garcia, J.I. Espeso, J. González, Beatriz Arce, Rafael Valiente, Garikoitz Beobide, Israel Cano, Rosa Martín‐Rodríguez, Imanol de Pedro, Jonathan Albo
Abstract
High Resolution Image Download MS PowerPoint Slide Considering CO 2 as an alternative and sustainable resource, rather than as a waste to be treated, this work proposes the combination of doped TiO 2 nanocrystals with optofluidics for the continuous photoreduction of CO 2 to alcohols under ultraviolet and visible light. This approach aims at overcoming one of the major limitations of this technology, namely, current photoreactor configurations and low activity under visible light of the up-to-date photocatalysts. Ce-doped and Cu–Ce-codoped TiO 2 nanocrystals, synthesized by a simple and green hydrothermal method with different Cu and Ce contents, are used in a planar optofluidic microreactor with an enhanced surface-area-to-volume ratio, uniform light distribution, and a larger photon receiving area. The results show promising alcohol production rates when doping the photoactive TiO 2 nanocrystals with Ce, which leads to a maximum rate of 116 μmol·g –1 ·h –1 for ethanol and 106 μmol·g –1 ·h –1 for methanol, exceeding most of the reported values for visible-light-driven CO 2 photoreduction to alcohol systems. It is worth noting that the system remains pseudostable for up to 6 h of continuous operation. Altogether, this work provides novel insights into the development of innovative systems for the transformation of CO 2 to alcohols under sunlight irradiation.