Using magnesium reduction strategy to produce black Ga2O3 with variable oxygen vacancies for photocatalytic applications

Gallium Oxide (Ga 2 O 3 ) exhibits great potential in photocatalysis due to its strong redox capability. Nevertheless, working in the deep ultraviolet region and having a high recombination rate limit its application. Using magnesium powder as the reducing agent, colored Ga 2 O 3 with different oxygen vacancy concentrations was prepared by a high temperature solid state reduction method. It is found that the band gap of Ga 2 O 3 is related to the concentration of oxygen vacancy , which can be controlled by reducing agents. Under 30 min of simulated solar light irradiation, black Ga 2 O 3 displays 86.2% degradation efficiency over Rhodamine B dye, which is about two times more than that for the white Ga 2 O 3 . Furthermore, after irradiation by the visible light for 120 min, the photocatalytic degradation efficiency of RhB dye for black Ga 2 O 3 increases to approximately 40.6% (26.3% for white Ga 2 O 3 ). Enhanced separation efficiency of the photogenerated carriers and local absorption of visible light are the main reasons for improved photocatalytic degradation efficiency. A novel method for studying Ga 2 O 3 and semiconductor oxides is established by the preparation of colored Ga 2 O 3 .