Carbon quantum dots supported AgI /ZnO/phosphorus doped graphitic carbon nitride as Z-scheme photocatalyst for efficient photodegradation of 2, 4-dinitrophenol

The unique attributes of CQDs, such as low cost, facile synthesis, tremendous photochemical, and physicochemical stability, render them as versatile nanocomposites, as compared to conventional semiconductors. Herein, a green synthesis approach was opted using naturally occurring bamboo leaves as precursors for CQDs production via a facile and efficient hydrothermal method. The fabricated CQDs were exploited for construction of Z-scheme P-doped g-C3N4/AgI/ZnO/CQDs (PGCN) heterojunction by immobilizing AgI/ZnO/CQD on graphitic carbon nitride (g-C3N4), that acts as support targeted for 2, 4-dinitrophenol (DNP) eradication from simulated wastewater. TEM image depicts the presence of different fringes on an agglomerated structure which confirms the formation of nanocrystalline heterostructure. XRD, XPS, FT-IR, and EDX were used to provide structural, morphological information of synthesized samples relating the existence of heterostructure between AgI and ZnO/CQDs with the sheet-like structured g-C3N4 which have undergone successful inclusion of P dopant into g-C3N4 framework. Congruously, the optical properties of modified photocatalyst with suppression in photogenerated electron-hole pair recombination g-C3N4/AgI/ZnO/CQD nanostructure were evidenced by photoluminescence (PL) spectra and UV-Vis diffused reflection spectra (UV-Vis DRS). Synergistic process of adsorption and photocatalysis was effectual for complete mineralization of DNP into CO2, H2O, and inorganic ions. The integration of g-C3N4 to AgI/ZnO with CQDs accelerated photocatalytic activity attributed to electron sink behavior of CODs. The fabricated Z-scheme P-doped g-C3N4/AgI/ZnO/CQDs photocatalyst exhibited remarkable stability and recyclability for ten consecutive catalytic cycles.