Binary doping of indium oxide with cobalt and iron: Promotion of the photothermal valorization of CO2

The catalytic valorization of carbon dioxide (CO 2 ) is a current challenge with implications in the mitigation of global warming, as well as to set up circular industrial processes. In this work, we present a novel photothermal approach to selectively convert it into carbon monoxide. To this end, the co-doping of nanostructured, high surface-area indium oxide is achieved using cobalt and iron. The joint use of microscopy and spectroscopic X-ray techniques was able to show that the two cations occupy cationic network positions of the oxide. Nevertheless, while cobalt is preferentially located at near-surface positions, iron occupies bulk ones. The catalytic response of the co-doped sample outperforms the single-doped materials and makes fruitful use of the combination of heat and light through a synergistic catalytic effect. The co-doped material would thus open a way to intensify the classical thermal process, rendering a highly active and selective system for the valorization of carbon dioxide.