Cobalt-Niobium Co-doping of Indium Oxide: Structural and Adsorption/Catalytic Properties for CO2 Valorization

Abstract

The co-doping of the indium oxide structure with cobalt and niobium is essayed using a microemulsion method to produce high-surface-area, mesoporous, functional materials. The co-doping leads to a major nanometric bixbyite oxide phase with both cations occupying cation positions, and affecting the size and shape of the oxide entities. For specific cobalt to niobium atomic ratios, the presence of a second surface phase is encountered. Such surface phase corresponds to an ill-defined indium hydroxide-type phase. The coexistence of the two phases is a unique phenomenon associated with the presence of both cations, which play a decisive role in promoting the CO₂ adsorption capability of the solids, as well as the valorization of the molecule under dual heat-light excitation. The co-doping of indium oxide thus appears to be a unique way to intensify the analogous thermal (classical) catalytic process for the elimination/valorization of carbon dioxide.