Solid-state Synthesis of Phase Pure CuBi2O4 by Sequential Ball Milling

Abstract

Bismuth-based metal oxides are an intriguing class of photoelectrode materials that can potentially enable large-scale solar hydrogen production via photoelectrochemical (PEC) water-splitting. For realizing such PEC devices, Kusachiite (copper bismuth oxide) is one of the most promising photocathode materials for high solar to hydrogen efficiency. Here we attempt to synthesize phase pure copper bismuth oxide (CuBi2O4) nanopowders using a facile solid-state reaction technique subsequently sintered at 750 0C for 4 h in air. These CuBi2O4 (CBO) powders have been further sequentially ball milled (SBM) up to 25 h to elucidate the milling duration effect on the optical bandgap of the ball milled CuBi2O4 (SBM-CBO). The structural, optical, and Raman studies suggest that phase pure tetragonal CBO could be grown from raw CuO and Bi2O3 powders. The variations in morphology and chemical composition of CBO with increasing milling hours were examined using field emission scanning electron microscopy (FE-SEM) and Energy Dispersive X-ray (EDX) microanalysis, respectively. The optical bandgap was measured in the range of 1.70 - 1.85 eV from the UV-VIS-NIR Diffuse reflection data of SBM-CBO powders. The CBO photocathode materials with variable structural and optical properties could be a promising candidate for self-sustained PEC generation of hydrogen fuel.Comment: 4 pages, 5 figures, 2022 4th International Conference on Sustainable Technologies for Industry 4.0 (STI