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.