Enhancing Nb2O5 activity for CO2 photoreduction through Cu nanoparticles cocatalyst deposited by DC-magnetron sputtering

[Display omitted] •The Cu deposition over Nb2O5 showed a high CO2 reduction capacity.•The Cu deposition decreases the recombination rate of the charges photogenerated.•The magnetron sputtering system provided a cluster of Cu highly dispersed.•The Nb2O5/Cu material showed high conversion for the methanol. Herein we demonstrate that the deposition of a small loading of Cu nanoparticles (0.51 wt %) by DC-magnetron sputtering over niobium oxide (Nb2O5) increases its photocatalytic activity for the reduction of carbon dioxide (CO2) into methane (CH4), methanol (CH3OH), acetone (CH3COCH3), acetic acid (CH3COOH), isopropanol (CH3CH(OH)CH3) and formate (HCOO−). The improvement in the CO2 photoreduction of the Nb2O5/Cu can be attributed mainly to a reduction in the recombination rate of the electron-holes pairs photogenerated due to the electron trapping by Cu species as observed by the photoluminescence analysis, high dispersion of Cu, and high specific surface area of material even after addition Cu.