Plasmonic Titanium Nitride Facilitates Indium Oxide CO2 Photocatalysis

Nanoscale titanium nitride TiN is a metallic material that can effectively harvest sunlight over a broad spectral range and produce high local temperatures via the photothermal effect. Nanoscale indium oxide-hydroxide, In2O3-x(OH)(y), is a semiconducting material capable of photocatalyzing the hydrogenation of gaseous CO2; however, its wide electronic bandgap limits its absorption of photons to the ultraviolet region of the solar spectrum. Herein, the benefits of both nanomaterials in a ternary heterostructure: TiN@TiO2@In2O3-x(OH)(y) are combined. This heterostructured material synergistically couples the metallic TiN and semiconducting In2O3-x(OH)(y) phases via an interfacial semiconducting TiO2 layer, allowing it to drive the light-assisted reverse water gas shift reaction at a conversion rate greatly surpassing that of its individual components or any binary combinations thereof.