New insights into heterogeneous generation and evolution processes of sulfate radicals for phenol degradation over one-dimensional α-MnO 2 nanostructures

•Three 1D MnO2 catalysts were applied to activate peroxymonosulfate.•Structure-dependent performance of MnO2 in phenol degradation was observed.•In situ radical generation and evolution was investigated by EPR and competitive radical tests.•Kinetics and degradation pathways of phenol were illustrated.