Functionalization Site Modulation Of Copper-based Catalysts And Its Mechanism Of Activation Of Peroxymonosulfate

Advanced Oxidation Processes（AOPs）based on persulfates exhibit the advantages of strong oxidation capacity,high reactivity and low environmental risk.In recent years,copper-based heterogeneous catalysts with low energy consumption and high natural reserves have proven to be ideal activators for persulfates.However,the activation of persulfates by copper oxides suffers from bottlenecks such as slow regeneration rates of low-valent metals and blocked electron transfer between catalyst and perovskite.In order to accelerate the Fenton-like activation rate and improve the utilization of the oxidant,this study systematically investigates the mechanism of enhanced catalytic oxidation performance by functionalizing the surface sites of copper-based catalysts,exploring the changes in the structural properties of the catalysts and resolving the interfacial microscopic reaction processes.Details are as follows:（1）Construction of multivalent composite Cucatalytic sites to facilitate the conversion of Cu（II）to Cu（I）during Fenton-like reactions.The metal-ligand derivatives,Cu₂O/CuO,were obtained by calcination at different temperatures under an air atmosphere.The Cu₂O/CuO complex showed excellent catalytic activity（100%bisphenol A’s removal over 30 min of reaction）and high stability in the activation of peroxymonosulfate（PMS）.The Cu₂O/CuO/PMS system mediated a radical/non-radical catalytic mechanism that was highly adaptable to a wide p H range（3～11）and a diversity of inorganic anions(SO₄^2-,NO₃^-,HCO₃^-,and Cl^-)for the effective degradation of bisphenol A.Experiments and characterizations indicated the presence of diverse reactive species in the system,including free radicals(^·OH,SO₄^·-)and non-radicals（Cu（III）,¹O₂,surface complexes）,and proposed a synergistic catalytic mechanism for the Cu（I）/Cu（II）/Cu（III）redox cycle.In addition,based on UPLC/MS results and toxicity assessment data,a possible oxidative degradation pathway for BPA was proposed,where the system could degrade bisphenol A to a less toxic or harmless small molecule.（2）Modulation of the surface oxygen defect of CuO to form an ultrafast short-range catalytic pathway for efficient activation of persulfate.CuO with rich oxygen vacancies（OVs）,MSCuO-300,was synthesised by introducing the molten salt（Na NO₂）and calcined at low temperature（300℃）under an air atmosphere to effectively degrade tetracycline hydrochloride（TTCH）(k=0.095 min^-1).The direct adsorption and activation of OV and its modulated Cu-O bonds played a dominant role,rather than the adsorption of surface hydroxyl groups,which formed a short-range catalytic pathway.The shortened catalytic path between the active site and the PMS accelerated the charge transfer at the interface,which facilitated the activation of the PMS,compared to Cu_xO-500 and commercial CuO,the activation rate of PMS was improved by 11.97 and 12.64 times,respectively.OVs contributed to the generation of the main active species(¹O₂,and O₂^·-).In addition,the MSCuO-300/PMS system showed promising practical applications,with less influence on parameters of the real water environment,such as p H（3 to 11）and anions,operating in continuous reactors for up to 168 h（100.0%removal rate）.This work deepens the understanding of the functionalised modulation of copper oxide multi active site complexes and surface oxygen defects for efficient activation of PMS to degrade organic pollutants,which provides a relevant theoretical basis that heterogeneous Fenton reaction mediated by copper-based catalysts to resolve refractory pollutants in wastewater.