Ni调控Zn基氧化物催化剂的异丁烷氧化脱氢性能OA北大核心

A series of ZnNiAl metal oxide-supported Zn-Ni bimetallic catalysts were prepared by roasting and reduction treatment using ZnNiAl hydrotalcite(ZnNiAl-LDH)as a precursor,which had a fixed(Zn+Ni)/Al molar ratio of 2 but varied in the Ni/(Zn+Ni)molar ratio(x=0,0.1,0.5,1.0,2.0).The effect of Ni substitution content on the structure,texture,surface chemical state,reducing ability,acidity and alkalinity and CO desorption properties of the Ni-Zn-Al catalysts were systematically explored,in connection with their catalytic performance in the oxidative dehydrogenation of isobutane(i-C4H10)with CO2(CO2-ODHB).The results indicate that Ni can control the composition and reduction ability of the substituted phase,optimize the pore structure and stabilize the catalytic performance in CO2-ODHB.Trace Ni substitution(x=0.1)helps to establish appropriate Zn-Ni-Al interactions in the ZNA-0.1-R catalyst,achieving suitable surface acidity and weak alkalinity,inhibiting carbon deposition and promoting the CO desorption and the elimination of carbon deposition,over which the conversion of i-C4H10 is stable(＞41％)with a selectivity of 90％to i-C4H8.However,excessive Ni substitution(x ≥ 0.5)can aggravate the side reaction due to excessive acidity and competitive adsorption of CO2,resulting in a significant increase in the selectivity to CH4.