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.