Degradation mechanism and properties of debris of photocatalytically degradable plastics LDPE-TiO2 vary with environments

•Environmental conditions affect photocatalytic degradation of LDPE-TiO2.•First report the effect of environments on degradation mechanism of LDPE-TiO2.•Organochlorine was first observed in the debris of LDPE-TiO2.•HO‧ in water containing NaCl attacks LDPE-TiO2 via reaction with Cl− forming Cl.