Nanorod β-Ga2O3 semiconductor modified activated carbon as catalyst for improving power generation of microbial fuel cell

Nanorod monoclinic β-Ga2O3 semiconductor, synthesized by a facile hydrothermal method, was firstly researched as a catalyst to modify activated carbon air cathode in microbial fuel cells (MFCs). The maximum power density of modified MFC reaching 1843 ± 40 mW m−2 was 3 times higher than the control. The Brunauer-Emmett-Teller (BET), transmission electron microscope (TEM), and X-ray diffraction (XRD) results revealed the larger surface area and porous structure could provide more active sites to improve the performance of MFCs. The result of X-ray photoelectron spectroscopy (XPS) confirmed that plenty of oxygen vacancy existed in the synthesized β-Ga2O3. Tafel curve and rotating disk electrode (RDE) results illustrated the high exchange current density of β-Ga2O3 and the four-electron pathway at the cathode during the oxygen reduction reaction (ORR), respectively. The cathode modified with β-Ga2O3 displayed excellent improvement towards ORR and therefore improved the performance of MFCs.