Synthesis of Highly Efficient (0D/1D) Z-Scheme CdS-NPs@ZnO-NRs Visible-Light-Driven Photo(electro)catalyst for PEC Oxygen Evolution Reaction and Removal of Tetracycline

Abstract

Herein, we synthesized the cadmium sulfide nanoparticles (CdS-NPs) coated zinc oxide nanorods (ZnO-NRs) core-shell like CdS-NPs@ZnO-NRs heterojunction for photo(electro)chemical applications. The CdS-NPs and ZnO-NRs were synthesized through a simple hydrothermal path. The physicochemical and optoelectronic properties of the as-prepared catalysts are characterized by various spectroscopy techniques, such as FTIR, XRD, SEM, TEM, EDX, VB-XPS, DRS, and PL. The photocatalytic performances of the CdS-NPs@ZnO-NRs catalyst were evaluated by photodegradation of tetracycline (TC) in aqueous media under visible-light irradiation, which demonstrated 94.07 % of removal (k’ = 0.0307 min−1) within 90 min. On the other hand, the photoelectrochemical (PEC) water-oxidation/oxygen-evolution reaction (OER) was performed, which resulted in the photocurrent density of 3.002 mA/cm2 and overpotential (at 2 mA/cm2) of 171 mV (vs RHE) in 1.0 M KOH under AM 1.5G illumination. The reactive species scavenging experiment demonstrates the significant contributions of photogenerated holes towards TC removal. Furthermore, the Z-scheme CdS-NPs@ZnO-NRs core-shell heterojunction exhibits high efficiency, recyclability, and photostability, demonstrating that the CdS-NPs@ZnO-NRs is a robust photo(electro)catalyst for visible-light PEC applications.