A hybrid mesoporous sheet-like NiCo2O4@P,S,N-doped carbon nano-photocatalyst for efficient synergistic degradation of Congo red: Statistical, DFT and mechanism studies

Abstract

Here, a hybrid mesoporous sheets-like nano-catalyst was used to investigate the degradation of Congo Red (CR) dye. The photocatalytic efficiency of CR dye degradation was evaluated using a variety of mesoporous hybrid materials containing P,S,N-doped carbon (PC1), CoO@P,S,N-doped carbon (PC2), NiO@P,S,N-doped carbon (PC3), and NiCoO@P,S,N-doped carbon (PC4) sheet-like. The results indicated that the PC4 nano-catalyst exhibited exceptional efficacy in the photocatalytic degradation of CR dye, achieving a degradation efficiency exceeding 99 %. The results also showed that PC4 possessed a band gap of 1.7 eV. To formulate an effective photodegradation system, Analysis of Variance (ANOVA), a valuable statistical method, was employed to examine how varying pH, PC dose, and irradiation time can improve the photodegradation performance. Influential key parameters, including pH, PC dose, irradiation time, and CR concentration, were optimized through response surface methodology applying a four-factor, three-level Box-Behnken design (BBD). To achieve a 99 % decolorization of CR, the optimum conditions were determined to be pH 3.8, PC dose at 14 mg, irradiation time of 10.2 min, and CR concentration of 14.3 ppm. Kinetic models demonstrated that CR degradation followed pseudo-first-order kinetics. Moreover, band gap comparisons, scavenger analysis, and density functional theory (DFT) were used to discuss the CR degradation mechanism.