One-Step Hydrothermal Method Realizing Oxygen Vacancy Construction and P Doping of MnO₂ to Optimize Its Oxygen Evolution Performance

MnO₂ is considered one of the most potential catalysts for the oxygen evolution reaction, but its activity, which is determined by its electronic structure, crystal phase, and morphology, needs to be improved further. However, it is difficult to realize these multiscale structural regulations of MnO₂ simultaneously during the preparation. In this study, α-MnO₂ nanomaterial with a lot of oxygen vacancies (O_Vs) and Mn³⁺ is prepared by a one-step hydrothermal method, during which the protons of HCl can take the oxygen atom away from MnO₂ to form a lot of O_Vs. The introduction of NH₄H₂PO₄ can realize P doping in MnO₂ to stabilize the product in the α-phase. In addition, the O_V and P can increase the content of Mn³⁺ and regulate the Mn-O bond length synergistically to optimize the reaction kinetics. As a result, the product shows obviously enhanced catalytic activity. This study provides a one-step method for multiscale structural regulation of MnO₂, which can easily create oxygen vacancies and achieve nonmetallic doping to optimize the oxygen evolution reaction (OER) performance of MnO₂.