Effective photocatalytic degradation of organic dyes using ZNC/rGO nanocomposite photocatalyst derived from ZIF-8/rGO thermolysis for water treatment

•Photocatalytic water treatment using nano-structured semiconductors.•Thermolysis of ZIF-8/graphene oxide composite affords a highly active photocatalyst for organic pollutant degradation.•New synthetic strategy based on coupling semiconductors to enhance the electron-hole separation and reduce the recombination of photogenerated charge carriers.•ZNC derived from ZIF-8 is a good n-type semiconductor and rGO is a highly conducting material.•ZNC/rGO was used to oxidize wastewater containing methylene blue dye to environmentally friendly substances (CO2 and H2O) under simulated solar light irradiation.