Syntheses and characterisation of p-type copper niobium oxides for photocatalytic hydrogen generation

Copper niobium oxides have small band gaps and can absorb visible light, making these materials promising for semiconductor photocatalysis. Their chemical stability also greatly surpasses those of the binary copper oxides, which are prone to photocorrosion. Herein, we thoroughly investigate the material system Cu-Nb-O and syn-thesise up to six different phase-pure and highly crystalline oxides: CuNbO3, CuNb13O33, CuNb3O8, monoclinic and orthorhombic CuNb2O6, and Cu3Nb2O8. Synthesis conditions have been optimised towards easier and more economic syntheses compared to known literature procedures, and all materials were thoroughly analysed with respect to optical and electronic properties and their chemical stability. All materials are utilised in photo -catalytic hydrogen evolution, with a heterojunction of monoclinic and orthorhombic CuNb2O6 being the most active one.

Automated summary

We thoroughly investigated copper niobium oxides and synthesized six different phase-pure and highly crystalline oxides. These materials have small band gaps and can absorb visible light, making them promising for semiconductor photocatalysis. They also have better chemical stability compared to binary copper oxides.