Research On Mixed Oxides Derived From Hydrotalcite-like Compounds For N₂O Decomposition

Greenhouse gas emissions is a topic of global concern, nitrous oxide （N₂O） become oneof the hot subjects on environment because of their high global warming potential. In thiswork, we make hydrotalcite-like precursors Co-M-Al series and Co-M-Al-Ce series bycoprecipitation, and prepare catalysts for catalytic decomposition of N₂O by hightemperature calcination, on the xperimental research of catalytic decomposition of N₂O, weachieved the following findings:（1）The XRD and FTIR results showed that the series of Co-M-Al and Co-M-Al-Ceprepareed by coprecipitation except Co0Cu3-HT belongs to hydrotalcite precursors. Thehydrotalcite-like precursors contain CeO2characteristic diffraction peaks with Ceintroduction. After calcination, the majority of hydrotalcite precursors form compositeoxides and own spinel structure when the content of Co is high.（2）Experimental study found that different series of catalysts have different catalyticdecomposition temperature when N₂O conversion rate were50%and90%. In the series ofCo-M-Al catalysts, the most active Co2.5Ni0.5catalytic’s T50and T90were417℃and469℃. In the series of Co-M-Al-Ce catalysts, the most active Co2.5Ni0.5Ce0.05catalyst’sT50and T90were310℃and380℃. In the series of K/Co-M-Al-Ce catalysts, the mostactive1.5%K/Co2.5Ni0.5Ce0.05catalytst’s T50and T90were310℃and380℃.the K/Co-M-Al-Ce series, the most active1.5%K/Co2.5Ni0.5Ce0.05catalytst’s T50and T90were261℃and346℃. Thus,1.5%K/Co2.5Ni0.5Ce0.05catalyst has better application prospectrelative to other two series of catalysts.（3）Ni-containing catalysts by XPS characterization results showed that after theintrodction of elements Ni, chemical environment surrounding Co has be changeed, and Coelectron transfer capability is improved, which may be the reason for the high activity of theCo2.5Ni0.5catalyst; After the introdction of elements Ce, the metal oxide particles are reduced and the dispersion are increased, which may be the reason for the high activity ofthe Co2.5Ni0.5Ce0.05catalyst; when K is loaded, the electron density around the cobaltincreases, it may result in weakening of the bond between the oxygen and reactive metal ions,and reduce the surface temperature reduction, thereby the activity of the catalyst is improved,which may be th reason for the high activity of the1.5%K/Co2.5Ni0.5Ce0.05catalyst.