Facile Fabrication of Novel Hetero-Structured Organic–Inorganic High-Performance Nanocatalyst: A Smart System for Enhanced Catalytic Activity toward Ciprofloxacin Degradation and Oxygen Reduction

In this study, a novel organic–inorganic polyaniline/silver/silver molybdate (PANI/Ag/Ag₂MoO₄) heterojunction nanocatalyst has been fabricated by in situ depositing Ag₂MoO₄ on p-type PANI to explore two different catalytic properties, e.g., photocatalytic degradation of antibiotic ciprofloxacin (CIP) and electrocatalytic reduction of oxygen. After hybridization of Ag₂MoO₄ with PANI, the p-n heterojunction developed and consequently z-scheme induced efficient photogenerated charge carrier separation and migration occur due to the internal electric field developed at the heterojunction interface. Compared with pure Ag₂MoO₄, the heterojunction nanocomposite possessed significantly enhanced photocatalytic activity as evidenced by the degradation of Congo Red (CR) dye under UV light irradiation. The optimum composite with 20 wt % PANI nanorods exhibited paramount photocatalytic activity over all the composites. Subsequently, 99.99% of CIP removal was achieved with this optimal composite within 40 min. On the other hand, it displays admirable electrocatalytic activity toward oxygen reduction reaction (ORR) compared to Ag₂MoO₄ with high ORR onset potential. It is worth mentioning that PANI was beneficial toward both improved photocatalytic and electrocatalytic activity. Our study provides a simple method to design and fabricate a semiconductor composite material with staggered band structure which exhibits enhanced photocatalytic and ORR performance.