Dual transfer channels in FeCN/ZnSe/V2O5 dual Z-Scheme ternary heterojunctions facilitating efficient degradation of Congo red dye

The current study investigates the fabrication of a dual Z-scheme photocatalytic system, i.e., FeCN/ZnSe/V2O5, to effectively remove Congo red (CR) dye. Recently, photocatalysis has gained popularity as a practical wastewater treatment approach due to using solar energy (a renewable energy source). All photocatalysts were synthesized using a simple and cost-effective method, such as thermal polycondensation and the hydrothermal method, to fabricate FeCN and ZnSe, respectively, while the calcination technique was used to construct bare V2O5. A physical mixing approach was used to form the binary and ternary heterojunctions of FeCN/ZnSe and FeCN/ZnSe/V2O5 heterojunction photocatalyst. By prolonging light absorption ability, lowering the recombination rate, and boosting charge separation efficiency, a dual Z-scheme route upgraded the photocatalytic performance of the ternary heterojunction photocatalyst. PL, EIS, and TPR investigations confirmed the lower recombination and higher charge transference in FeCN/ZnSe/V2O5 ternary heterojunction. The synthesized FeCN/ZnSe/V2O5 ternary heterojunction performed better photocatalytic efficiency towards CR degradation than other photocatalysts, 87% during 60 min of light irradiation. The ESR studies with scavenging investigations also established the crucial part of •O2⁻ and •OH species during photodegradation. Also, recyclability experiments were performed to explore the stability of the synthesized ternary heterojunction photocatalysts, and ~78% removal efficiency was attained after 5 catalytic cycles, indicating its good reusability with stability. Graphical Abstract