Study on the synthesis of MnOx/CN/Ag composites and catalytic performance in degrading organic pollutants

Volatile organic compounds (VOCs) pose severe threats to the environmental sustainability and human health, necessitating the development of efficient degradation technologies. Photothermal catalysis, combines the advantages of photocatalysis and thermal catalysis, has emerged as a promising strategy for the degradation of VOCs. Manganese oxides (MnO _x ) and carbon nitride (CN) have attracted much attention due to their excellent photocatalytic properties. Notably, the introduction of the precious metal silver (Ag) further enhances the catalytic activity through synergistic effects. In this study, the MnO _x /CN/Ag composite was prepared by precipitation method. The structure and morphology of the material were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Light absorption capacity, charge transfer efficiency and carrier recombination ability have been evaluated using UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), electrochemical impedance spectroscopy (EIS) and photoluminescence spectroscopy (PL). The photothermal catalytic performance toward toluene and tetracycline hydrochloride (TC) was assessed, then the reduction properties were analyzed by H ₂ -temperature programmed reduction (H ₂ -TPR). The results show that the MnO _x /CN/Ag composites achieves a degradation efficiency of 97% for toluene at 260℃ and a TC degradation efficiency of close to 80%. The superior catalytic performance and stability of the composite can be attributed to abundant oxygen vacancy and low reduction temperature. This work not only provides a novel photothermal catalytic material for enhancing VOCs degradation but also offers insights into the treatment of multiply environmental pollutants.