Development\nof a SnNb<sub>2</sub>O<sub>6</sub>‑Based\nDirect Z‑Scheme Heterojunction: A Novel Approach for Efficient\nTetracycline Photocatalytic Degradation

With ever-increasing attention toward the removal of\npharmaceuticals\nand personal care products (PPCPs), it is highly essential to study\npromising approaches for this purpose. We introduced a novel Z-scheme\nSNO-ACO photocatalyst developed via hydrothermal precipitation for\ndegrading tetracycline (TC-HCl) under visible light. SNO-ACO-9% achieved\n93% TC-HCl removal in 30 min, with a high pseudo-first-order kinetic\nrate (0.064 min<sup>–1</sup>), 3.5 times faster than SNO, demonstrating\nexceptional efficiency and potential in environmental remediation,\nespecially for antibiotic pollution. The photocatalyst’s mechanisms\ninvolve enhanced light absorption and charge separation, which was\nfacilitated through the addition of a strong oxidative photocatalyst,\nAg<sub>2</sub>CO<sub>3</sub>, in a comparatively low amount in ratio\nto the parent reductive photocatalyst, SnNb<sub>2</sub>O<sub>6</sub>, without using a third agent as a charge mediator. Electron spin\nresonance (ESR) and scavenging experiments verified the formation\nof different reactive oxygen species and the Z-scheme heterojunction\nmechanism. This study will provide insight into using a more efficient\nsystem with heightened overall photodegradation activity in emerging\ncontaminant removal.