Synthesis Of Tranition Metal Single Atom-doped Carbon Materials Catalysts And Applied To The Degradation Of Micro-pollutants In Water

In recent years,heterogeneous catalysts based on new nanomaterials have attracted more and more attention in environmental remediation.The electronic structure of the support will be changed when single atom is attached or embedded in the support structure,which will affect the catalytic performance,and the support for the single atoms'adsorption stability also plays an important role.Nitrogen-doped reduced graphene oxide?rGO?has the advantages of large surface area and high mechanical strength.It can be used as an ideal support material for the manufacture of various graphene-based composite materials.Graphite-phase carbon nitride?g-C₃N₄?has convenient and stable synthesis.It can be used as an excellent matrix to support metal atoms because it's high performance,excellent electronic band structure,rich synthetic elements and other excellent properties.In this research,nitrogen-doped reduced graphene oxide-supported monoatomic copper materials?SA-Cu/rGO?and graphite-phase carbon nitride-supported monoatomic chromium materials?SA-Cr/g-C₃N₄?were synthesized,and used fenton-like reactions to degradation pollutants.Detonation method was used to degrade the pollutants to investigate their performance.X-ray photoelectron spectroscopy?XPS?,transmission electron microscopy?TEM?,extended X-ray absorption fine structure spectroscopy?EXAFS?,electron spin resonance spectrometer?ESR?,and scanning electron microscopy?SEM?were used to analyze the two materials.Characterized.Rhodamine B?RhB?,sulfa antibiotics?SAs?,and bisphenol A?BPA?were selected as target pollutants.The degradation performance of two single-atom catalysts was investigated.The main content of the study consists of the following three parts:?1?Study on the degradation of Rhodamine B by single-atom catalyst activated hydrogen peroxide under visible lightThe SA-Cr/g-C₃N₄ sample prepared as a Fenton-like catalyst showed remarkable catalytic activity and excellent stability in a wide pH range of activated H₂O₂ under visible light irradiation.The kinetic rate of SA-Cr/g-C₃N₄ catalytic degradation of organic dyes is 6 times that of pure g-C₃N₄.What's more,a wide range of trace pollutants including sulfamethoxazole?SMX?,bisphenol A?BPA?,acetamiprid?ACE?and tetrabromobisphenol A?TBBPA?have been passed through the photofenton-like method described above successfully oxidized.ESR analysis and quenching experiments show that·OH radicals are the main active substances responsible for the efficient oxidative degradation of trace pollutants.?2?SA-Cr/g-C₃N₄ combined with visible light activated H₂O₂ to degrade bisphenol AIt was found that SA-Cr/g-C₃N₄ showed excellent performance,excellent cycle stability,and a wide pH range?3.0 to 11.0?suitable for BPA degradation applications,with high degradation and mineralization efficiency??98%?.The combination of X-ray absorption fine structure analysis and DFT mechanical studies revealed that the Cr?II?-N₄ position in pyrrole-rich g-C₃N₄ is more effective for generating·OH radicals through H₂O₂ activation.This findings may provide some guidance for the rational design and manufacture of new multifunctional SACs for environmental remediation.?3?SA-Cu/rGO activated PMS to degrade sulfa antibioticsThrough heterogeneous activation of persulfate monosulfate?PMS?,single-center copper atoms embedded in reduced graphene oxide?SA-Cu/rGO?can degrade various antibiotics,including sulfamethoxazole?SMX?,meropenem and sulfafuran.Compared with pure rGO,SA-Cu/rGO showed enhanced catalytic activity,the SMX degradation rate increased from 73.48%to 99.62%in 60 minutes,and the corresponding first-order kinetic rate increased from 0.018 min^-1 to 0.088 min^-1.In addition,SA-Cu/rGO also shows excellent durability over a wide pH range and has good reusability.After 5 cycles,the catalytic performance remains above 90%.The results of ESR analysis and quenching experiments show that·OH and SO₄^·-free radicals and singlet ¹O₂ are the main active species for SMX oxidat ion.The synergistic combination of r-GO and exposed Cu active sites can improve catalytic performance.It promotes the pre-enrichment of pollutants through adsorption and the in situ interaction of pollutants with active free radicals on the surface.This study provides a new strategy for the rational design and synthesis of graphene-supported monoatomic Cu catalysts,and provides new insights into the application of SA-Cu/rGO in environmental remediation.