Various reactors reported in literature for H2O2 production and contaminants degradation:(a) Carbon nanotube membrane stack filter (Adapted with permission (Gao et al., 2015). Copyright 2015, American Chemical Society), (b) 3-electrode flow-through reactor (Adapted with permission (Zhou et al., 2018d). Copyright 2018, Elsevier), and (c) vertical-flow reactor (Adapted with permission (Ren et al., 2016). Copyright 2016, Elsevier).