Preparation Of Palladium-based Catalyst By Plasma-assisted Atomic Layer Deposition And Its Applications In CO Oxidation And CO₂ Reduction

Supported Pd catalyst is an important noble metal material,which has become a research hotspot in recent years due to its high catalytic performance in CO oxidation and CO₂ reduction.However,since Pd is a rare noble metal,it is expensive to prepare.Therefore,it is very important to find a more efficient and stable preparation method to produce highly active Pd catalytic materials on the basis of traditional preparation methods.In this thesis,the use of plasma-assisted atomic layer deposition as a green,efficient and safe method provides a new idea for the preparation of Pd catalytic materials,the effects of Pd-based catalysts on CO oxidation and CO₂ reduction properties were investigated.（1）In this thesis,Pd/ASM catalysts with different loadings were prepared by plasma-assisted atomic layer deposition using palladium hexafluoroacetylacetonate as the precursor and porous material（30%γ-Al₂O₃,20%molecular sieve and 50%aluminum silicate,labeled as ASM）as the carrier.The catalysts were characterized by XRD,XPS,BET and TEM.The effects of different loadings of Pd catalysts on the catalytic CO oxidation performance was investigated.when the loading of Pd was 2 wt%,the catalytic effect was the best,and CO could be completely converted at 140°C.（2）In this thesis,Pd/γ-Al₂O₃,Fe₂O₃/γ-Al₂O₃ and Pd-Fe₂O₃/γ-Al₂O₃ catalysts were prepared by chemical impregnation and plasma-assisted atomic layer deposition usingγ-Al₂O₃ as the carrier and palladium hexafluoroacetylacetonate and iron nitrate as the metal precursors.The effects of plasma only,plasma+γ-Al₂O₃,Pd/γ-Al₂O₃,Fe₂O₃/γ-Al₂O₃ and Pd-Fe₂O₃/γ-Al₂O₃ catalysts on CO₂ hydrogenation reduction performance were compared,the results showed that the Pd-Fe₂O₃/γ-Al₂O₃ catalyst has the best catalytic effect,and the conversion rate of CO₂ was 16.3%.And by examining the influence of discharge power and the molar ratio of H₂/CO₂ on the catalytic performance of carbon dioxide catalytic hydrogenation,the optimized experimental conditions were obtained:when the ratio of H₂/CO₂ was 4,and the discharge power was 19.6 W,the conversion of CO₂ was 16.3%,and the selectivity to CH₃OH was 26.5%.