An efficient gravity-driven catalytic membrane was developed in the current study. By taking advantage of its great surface area and high porosity, we prepared MnO2 nano-catalysts onto a polydopamine-coated nanofibrous substrate to achieve the combination of high catalyst loading (up to 9.7 wt%) and high water permeability (6155 +/- 448 L m(-2) h(-1) bar(-1)). In this approach, polydopamine was used as a green template for the spontaneous immobilization of MnO2 from a potassium permanganate solution, which resulted in uniformly-dispersed nano-catalysts without the need of strong reducing agent. Gravity-driven catalytic filtration results showed efficient removal (> 95%) of the model pollutant methyl blue. This gravity-driven catalytic filtration process may open new opportunities for contaminant removal with high efficiency and low energy consumption.