Plasmonic enhancement of CO2 conversion to methane using sculptured copper thin films grown directly on TiO2

• Cu sculptured thin films (STFs) directly grown on TiO2 catalytic films
• Excellent performance in methane production rate by TiO2/Cu STFs films
• Enhancement in methane production by plasmonic effect of Cu STFs

Columnar Cu nanostructures with tunable lengths are formed directly on porous TiO2 by oblique-angle electron beam evaporation and used as a cocatalyst for photocatalytic conversion of CO2 to methane. A remarkable enhancement in methane production rate is measured using the sculptured copper films with a maximum of 124.3 ppm · cm− 2 · h− 1 for 160 nm long Cu columnar structures under AM 1.5 illumination. This high methane production rate is attributed to a plasmonic enhancement effect due to the columnar Cu nanostructures.