Modification Synthesis Of Cu/Zn/m-ZrO₂ Catalyst And Study On Methanol Synthesis By CO₂ Hydrogenation

In recent years,the excessive emission of carbon dioxide has caused great environmental problems.Converting carbon dioxide into chemical raw materials is an effective way to solve this problem and produce renewable energy.Carbon capture and utilization have received widespread attention from researchers.Technology has promoted a sustainable circular economy promoted industrial symbiosis and economic growth,and made it possible to store renewable energy.Methanol is an important industrial chemical with a wide range of uses.As a raw material for a variety of products,and as a substitute for fuel additives and transportation fuels,global demand is huge.The Cu/Zn/Zr catalyst shows good performance in the methanol synthesis from CO2 hydrogenation,but it is far from meeting the requirements of industrialization.This work improves the performance of carbon dioxide hydrogenation to methanol by modifying the Cu/Zn/Zr catalyst.First,by adding different surfactants,it was found that the Cu/Zn/Zr catalyst added with P123 had the best catalytic effect.On this basis,the ratio of Zr/(Cu+Zn)was adjusted and Zr/(Cu+Zn)=0.5:1,the catalyst has the best catalytic effect.The conversion rate of carbon dioxide was 13.8%,the selectivity of methanol was 68.1%,and the STY of methanol reached 150 mg g-1 h-1.Compared with Cu/Zn/Zr catalyst without added surfactant,the carbon dioxide conversion rate is increased by 5.3%,the selectivity of methanol is increased by 19%,and the space-time yield of methanol is doubled.Secondly,Cu/Zn/Zr catalyst with Zr/(Cu+Zn)=0.5:1 was doped with different of Y.It was found that the catalytic effect was best when Y/(Y+Zr)=0.05.The conversion rate of carbon dioxide was 18.2%,the selectivity of methanol was 73.5%,and the STY of methanol reached 220 mg g-1h-1.Compared with Cu/Zn/Zr catalyst without added surfactant,the conversion rate of carbon dioxide is increased by 4.4%,the selectivity of methanol is increased by 5.4%,and the STY of methanol is increased by 46%.It was found that adding an appropriate amount of Y can promote the exposure of active sites and is beneficial to the adsorption of CO2.Finally,different reducing agent were added to the precursor sulution of Cu/Zn/Zr catalyst with Zr/(Cu+Zn)=0.5:1,and the best catalytic effect.The conversion rate of carbon dioxide was 20.3%,the selectivity of methanol was 75.3%,and the STY of methanol reached 251 mg g-1h-1.Compared with Cu/Zn/Zr catalyst without added surfactant,the conversion rate of carbon dioxide is increased by 47%,the selectivity of methanol is increased by 10%,and the space-time yield of methanol is increased by 67%.It was found that the addition of a certain reducing agent produced Cu+ active site.At the same time,preformation of formaldehyde also increased the semiconductor ZnO phase crystals.Due to the synergy between CuO particles and the crystallized semiconductor ZnO phase,it exhibits good performance in the process of CO2 hydrogenation to methanol.