A new visible-light-responsive carbon–nitrogen-co-doped zinc oxide photocatalysts: Applications on dye remediation

C–N-co-doped ZnO was successfully developed as a visible-light photocatalyst by incorporating carbon (C) and nitrogen (N) into the ZnO lattice using a two-step sol–gel and physical grinding method. Characterizations included DRS, FTIR, XRD, SEM, XPS, and TGA all confirming successful doping. The DRS analysis confirmed the shift in photoresponse from the UV region to the visible-light region. The XRD analysis confirmed the hexagonal wurtzite structure of ZnO, with slight redshifts in 2θ values for the 5% C–N–ZnO NPs. SEM images showed particles of varying sizes while the XPS analysis confirmed the presence of C, N, Zn, and O. The C–N-co-doped ZnO exhibited enhanced photocatalytic activity, decomposing 91% of methylene blue in 140 min under visible light. The degradation followed a pseudo-second-order kinetic reaction, with decomposition rates increasing with higher photocatalyst quantities and decreasing with higher dye concentrations.

Uniform and stable C–N-co-doped nanocomposites were prepared and their excellent photocatalytic dye degradation under visible-light irradiation was observed.