α-MnO2 activation of peroxymonosulfate for catalytic phenol degradation in aqueous solutions

► α-MnO2 catalysts in nanosphere, nanorod and nanowire were synthesized. ► α-MnO2 can effectively activate peroxymonosulfate for phenol degradation. ► Nanowired α-MnO2 presented the highest activity with stable performance. ► Phenol degradation on α-MnO2 followed the first order kinetics.