Study On Microwave Catalysis And Low Temperature Catalytic Methane Dry Reforming Of Ni-based Catalysts

The proposal of carbon neutrality and carbon peaking makes the adsorption and conversion of carbon dioxide a hot spot,and the trend of replacing traditional energy sources with new energy sources such as methane is irresistible.Methane carbon dioxide dry reforming can both"eat"carbon dioxide and generate syngas（H₂,CO）.In this reaction process,nickel-based catalysts have activity comparable to noble metal catalysts but are cheap,but their defects such as carbon deposition and sintering lead to deactivation.This feature attracts the attention of researchers to design new Ni catalysts or new methods to apply methane drying.in the reforming reaction.In this paper,microwave catalysis is used to reduce the carbon deposition and reaction energy consumption of Ni-based catalysts,and high-activity Ni-based catalysts are developed to realize low-temperature catalysis to reduce the sintering deactivation of Ni-based catalysts.The prepared catalysts were subjected to XRD,TPR,XPS,Raman,TG,BET,TEM and other series of characterization analyses,systematically investigated the catalytic performance of the catalyst for methane dry reforming reaction.The main research contents are as follows:（1）Ni-M/Ce O₂ catalysts were prepared by impregnation method,where M is La and Co.The types of additive metals and the performance differences between the microwave mode and the conventional mode were explored.It is found that the introduction of additives can improve the activity and stability of the catalyst.The Ni-La/Ce O₂ catalyst with the best activity is at 2wt.%La content.Ce O₂ is used as the carrier after calcined twice by temperature-programmed hydrothermal method.The calcination temperature of the catalyst is 800℃.The best activity.At the same time,its activity in microwave reaction mode（MCRM）is higher than that in conventional reaction mode.Ni-Co/Ce O₂ has the best stability under microwave,and its stability under microwave catalysis is higher than that of conventional mode.（2）A novel class of Ni and semiconductor metal oxide hybridized nanostructured Ni catalysts Ni/@-Zr O₂/SBA-15 were prepared by co-precipitation,and Ni-Mo/@-Zr O₂/SBA-15 catalysts were prepared by adding additive Mo to Ni/@-Zr O₂/SBA-15by impregnation.The effects of different metal oxides,Ni content and additive Mo in hybrid nanostructured catalysts on hybrid nanostructured Ni catalysts were investigated,and their catalytic activity and stability at low temperatures of 500°C were investigated.It was found that Zr O₂ and Ce O₂ in the hybrid nanostructured catalysts exhibited high catalytic activity at low temperatures of 500°C and the difference in activity between the two was small;the activity of Ni content of 10wt.%was the best;the auxiliary Mo greatly improved the stability of Ni-Mo/@-Zr O₂/SBA-15 catalyst at a low temperature of 500°C,and the activity effect at lower temperatures was small,but the activity was inhibited at high temperatures;Ni-Mo/@-Zr O₂/SBA-15 catalyst has a CH₄ conversion rate of 8.3%and a CO₂ conversion of 12.7%at 500°C,and the comparison experiment with the comparison sample Ni/SBA-15 shows that all hybrid nanostructured Ni catalysts have higher activity and stability.（3）The hybrid nanostructured Ni catalyst Ni/@-Zr O₂/MCM-22 was prepared by co-precipitation method,the effect of different semiconductor Zr O₂ content was explored,and the catalyst activity under Ni/15%@-Zr O₂/MCM-22 was found.The highest,the catalytic activity of the hybrid nanostructured Ni catalyst is much higher than that of the common supported Ni catalyst Ni/MCM-22,and it has better stability at 500°C.