Preparation And Properties Of Platinum-loaded Metal-Organic Framework Composite Nano-Catalysts

Many researchers have found that the composites based on metal-organic framework(MOF)can be applied in sewage treatment,organic catalysis,environmental pollution control,food safety,photocatalysis,defect engineering and supercapacitors.Precious metal nanoparticles play an important role in the field of catalysis.Hence,the nanocomposites based on MOF have attracted great attention.Most of MOF are microporous in nature,and the low-dimensional and hierarchical structure of MOF is often beneficial for the reactant species to reach the catalytic center and its diffusion paths become shorter.Based on this,three kinds of platinum-loaded MOF nanocomposite materials were prepared using low-dimensional MOFs as carriers,and their catalytic properties were studied using a variety of dyes and 4-nitrophenol(4-NP)as the research objects.The specific research work is as follows:1?Mn-BTC/GO was prepared in the dispersion of graphene oxide(GO)using Mn(CH₃COO)₂·4H₂O and pyromellitic tricarboxylic acid(H₃BTC)as a precursor.Pt NPs was loaded on the Mn-BTC/GO carrier using chloroplatinic acid as platinum source.The morphology and structure were characterized by SEM,XRD and XPS.The catalytic performance and kinetics of Pt NPs@Mn-BTC/GO for 4-NP in aqueous solution were analyzed,and the degradation performance of the catalyst for various dyes was verified.After 9 catalytic cycles,the catalyst still maintained 85%degradation efficiency and had high activity.2?Mn-BDC was synthesized by the solvothermal method using Mn(CH₃COO)₂ 4H₂O and terephthalic acid(PTA)as a precursor.Pt NPs was loaded on the MOF carrier of the Mn-BDC by the surface adsorption using chloroplatinic acid as a metal source,and finally Pt NPs@Mn-BDC was obtained.It was characterized by SEM,TEM and other technology.The catalytic performance and kinetics of Pt NPs@Mn-BDC for methylene blue were discussed,and the selectivity for methylene orange,methylene blue and carmine were analyzed.The results show that the catalyst maintains high catalytic activity after many catalytic cycles and the degradation efficiency is more than 85%.3?Co-3DHFLM(Co-based three-dimensional layered flower material)was synthesized by the solvothermal method using Co(NO₃)₂ 6H₂O and 2-methylimidazole as a precursor.Pt NPs@Co-3DHFLM was obtained by the surface adsorption using chloroplatinic acid as metal source.It was characterized by XRD,SEM and TEM.The results show that the precious platinum nanoparticles is well distributed on the surface of the carrier,and the structure of the carrier is intact.The catalytic performance and kinetic analysis of Pt NPs@Co-3DHFLM for carmine were discussed,and the degradation performance of 4-NP was evaluated.The experimental results showed that the catalyst maintained 87%degradation efficiency and good catalytic activity after 9 catalytic cycles.