Plasmonic Titanium Nitride Facilitates Indium Oxide CO2 Photocatalysis

Abstract

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, In₂ O_{3- 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 @In₂ O_{3- x} (OH)_y are combined. This heterostructured material synergistically couples the metallic TiN and semiconducting In₂ O_{3- 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.

Keywords: CO 2 photocatalysis; indium oxide; photothermal; plasmon resonance; titanium nitride.