Synthesis of a UiO-66/g-C(3)N(4) composite using terephthalic acid obtained from waste plastic for the photocatalytic degradation of the chemical warfare agent simulant, methyl paraoxon

In our study, Zr-based UiO-66 (Zr) was synthesized using terephthalic acid obtained from waste plastic. Thereafter, UiO-66/g-C(3)N(4) composites were prepared by the solvothermal method, and their photocatalytic activity in the photodegradation of the chemical warfare agent simulant, dimethyl 4-nitrophenyl phosphate (DMNP), was evaluated. The as-synthesized UiO-66/g-C(3)N(4) exhibited a high surface area (1440 m(2) g(−1)) and a high capillary volume (1.49 cm(3) g(−1)). The UiO-66/g-C(3)N(4) samples absorbed a visible light band with bandgap energies of 2.13–2.88 eV. The as-synthesized UiO-66/g-C(3)N(4) composites exhibited highly efficient degradation of DMNP with a short half-life (t(1/2) of 2.17 min) at pH 7 under visible light irradiation. The trapping experiments confirmed that the h(+) and ˙O(2)(−) radicals played an important role in the photocatalytic degradation of DMNP. The UiO-66/g-C(3)N(4) catalyst simultaneously performed two processes: the hydrolysis and photocatalytic oxidation of DMNP in water. During irradiation, a p–n heterojunction between UiO-66 and g-C(3)N(4) restricted the recombination of photogenerated electrons and holes, resulting in the enhancement in the degradation rate of DMNP.