Development of ultrathin 2D layered titanate Pt/K₂Ti₄O₉/rGO nanocomposites for enhanced visible active photocatalytic detoxification of harmful organic pollutants

In this work, different wt% of rGO-loaded Pt-K₂Ti₄O₉ (x = 2.5, 5, 7.5, 10, and 12.5 wt%) nanocomposites were prepared by a facile hydrothermal process and used for the degradation of two different dyes such as congo red (CR) methylene blue (MB) and tetracycline (TC) antibiotic solution under visible light illumination. The bare K₂Ti₄O₉ (labeled as KTO) and the most active Pt-K₂Ti₄O₉/5% rGO (labeled as Pt-KTO/5% rGO) composite catalysts were thoroughly characterized by XRD, FT-IR, Raman, XPS, FE-SEM with EDS, HR-TEM, UV-DRS, and PL analyses. The photocatalytic activity of Pt-KTO/5% rGO was remarkable compared to bare KTO and other rGO-supported catalysts. Pt-KTO/5% rGO composite photocatalyst showed enhanced photocatalytic degradation of 97%, 99%, & 99% for CR, MB & TC at 180, 120 and 180 min, respectively. Mineralization of dyes (TOC of 85%, 87%, and COD of 76%, 79% for CR, MB) and antibiotics (TOC of 78% and COD of 69% for TC) was confirmed by chemical oxygen demand (COD) and total organic carbon (TOC) measurements. The Pt-KTO/5% rGO catalyst showing the highest activity also demonstrates recyclability. A suitable photocatalytic reaction mechanism has been proposed for the higher activity of Pt-KTO/5% rGO composite catalyst under visible light irradiation.