Unveiling the potential of NiFe layered double hydroxide (LDH)/CuWO4 S-scheme heterojunction for sulfamethoxazole photodegradation and nitrobenzene photoreduction to aniline

S-scheme heterojunction of NiFe layered double hydroxide (LDH) loaded onto CuWO4 was constructed via a hydrothermal approach. Different characterization techniques were used to understand the morphology, particle size, surface area, chemical composition, and crystallinity of photocatalysts. The NiFe/CuWO4 heterojunction was employed for photodegradation of sulfamethoxazole and the photoreduction of aniline. The photodegradation activity of sulfamethoxazole was conducted under different conditions of pH, time, photocatalytic dosages, and pollutant concentration. DFT calculations were used to calculate the EHOMO, ELUMO, fermi level and work function to understand the distribution of electron density around the atoms. The NiFe/CuWO4 almost degraded 95% of 20 mg/L sulfamethoxazole within 30 min at pH=6, almost double that of pristine NiFe and CuWO4. Furthermore, the recyclability test showed only a 10-12% decrease in the photodegradation efficiency of sulfamethoxazole after six catalytic cycles that display higher stability of NiFe/CuWO4 heterojunction. Further, the photocatalytic reduction of nitrobenzene to aniline was carried out at room temperature without any external reducing agent. NiFe/CuWO4 displays a maximum aniline yield of 90% in 240 min with 100% selectively.