O,N-Codoped CeF₃ Upconversion Nanoparticles for Efficient Photocatalytic Oxygen Evolution under Visible Light

Visible light response is as important as energy band potential for photocatalytic water splitting. In this work, upconversion CeF3 nanoparticles are developed by O and N doping. The contents and species of O and N regulated by various temperatures act on the large-scale regulation of defects and band structures distinctly, which can suppress the recombination of photogenerated carriers. O,N-CeF3-160 nanoparticles establish the most suitable defects and electronic structure in all O,N-CeF3 nanoparticles. It exhibits the optimal oxygen evolution rates up to 1277 μmol g–1 h–1, whose apparent quantum yield (AQY) is up to 53.09% at 550 nm. The photoluminescence (PL) spectra and density of state (DOS) illustration elucidate the internal reason for the distinct photocatalysis activity. Defects are just as important as band structure in the modification of O,N-codoped CeF3 upconversion nanoparticles. This work provides the approach to regulate CeF3 upconversion materials to achieve better photoactivity under visible light.