Facile fabrication of three-dimensional MnO2 for trichloroethylene degradation by plasma catalysis

•3D MnO2 catalysts were fabricated by a facile one-pot hydrothermal method.•MnO2 IV with hierarchical flower-like structure exhibited the best activity in NTP.•The abundant defects and vacancies in MnO2 IV facilitated oxygen species utilization.•RSM method indicated that applied voltage has the greatest impact on both MR and EY.•TCE degradation mechanism was proposed based on the detection of various species.