Thermo-sensitive C ₃ N ₄ for efficient photocatalytic degradation of methyl orange

The advancement of industrialization has led to severe environmental challenges stemming from inadequate pollutant management. Photocatalytic technology has emerged as a research focus due to its eco-friendly nature and high degradation efficiency. However, the widespread application of photocatalysts is hindered by limitations in recoverability and reusability. Therefore, designing high-performance photocatalysts with facile recoverability has become a critical research direction. Thermo-responsive materials, which precipitate upon heating and disperse upon cooling, offer a promising solution for enhancing recovery efficiency. In this study, a composite photocatalyst with thermo-responsive properties was successfully synthesized by combining graphite carbon nitride (g-C₃N₄) with the thermo-responsive copolymer NIPAM-DADMAC (poly(<i>N</i>-isopropylacrylamide)-<i>co</i>-diallyl dimethylammonium chloride). Key parameters including the optimal mass ratio of g-C₃N₄ to DADMAC-NIPAM, and the optimal recovery conditions were systematically determined by measuring the material's lower critical solution temperature (LCST). Experimental results demonstrated that under visible light irradiation, the composite photocatalyst achieved a remarkable 98.15% degradation rate of methyl orange (MO) within 120 min. Moreover, the composite exhibited exceptional stability and reusability, retaining over 77.92% of its degradation efficiency even after eight consecutive cycles. Additionally, its inherent thermo-responsive nature enabled highly efficient recovery of the catalyst. This research provides valuable insights and a novel strategy for the development of high-performance photocatalysts with enhanced recyclability, holding significant potential for practical applications in environmental remediation.