Dramatic coupling of visible light with ozone on honeycomb-like porous g-C 3 N 4 towards superior oxidation of water pollutants

•Honeycomb-like porous g-C3N4 was fabricated via a one-pot template-free method.•PGCN triggered a vigorous synergy between photocatalysis and ozonation.•Vis/O3/PGCN led to almost complete mineralization of PHBA.•The enhanced mineralization was due to systematically promoted generation of OH.•The mineralization procedure of PHBA in Vis/O3/PGCN was proposed.