Elucidating the effect of barium halide promoters on La_(2)O_(3)/CaO catalyst for oxidative coupling of methane  

作　　者：Yue Wang Xiao Yang Fumin Yin Kai Zhang Hongfei Guo Guowei Wang Guiyuan Jiang Chunyi Li Xiaolin Zhu 

机构地区：[1]State Key Laboratory of Heavy Oil Processing,China University of Petroleum,Qingdao 266580,Shandong,China [2]State Key Laboratory of Heavy Oil Processing,China University of Petroleum,Beijing 102249,China

出　　处：《Journal of Energy Chemistry》2022年第10期49-59,I0003,共12页能源化学（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(22178390,21961132026);the Key Research and Development Plan of Shandong Province(2018GGX107011);the Natural Science Foundation of Shandong Province(ZR2017BB020)。

摘　　要：The industrialization of oxidative coupling of methane(OCM)is restricted by the low once through yield of C_(2)hydrocarbons.Recently,the halogen-assisted OCM process has been attempted to overcome this issue,but the reaction stability was poor due to the rapid loss of gas-phase halides or molten alkali halides.In this work,the barium salts,particularly barium halides(BaCl_(2)and BaF_(2)),were demonstrated to be efficient promoters to improve the OCM reactivity of La_(2)O_(3)/CaO catalyst by increasing both C_(2)selectivity and C_(2)H_(4)/C_(2)H_(6)ratio,and simultaneously achieving outstanding reaction stability.The promoting mechanism can be understood in two aspects.On the one hand,the introduction of barium salts increased the amount of surface electrophilic oxygen species,serving as the alkaline active sites for selective methane activation.On the other hand,the barium halide additives induced the in-situ formation of methyl halide intermediates facilitating C_(2)H_(6)dehydrogenation,and their intimate contact with catalyst substrate restricted the rapid halogen loss and thereby improved the catalytic stability.This work not only provides a class of efficient OCM catalyst,but also offers a highly stable halogen-assisted reaction strategy.

关 键 词：Oxidative coupling of methane La_(2)O_(3)/CaO catalyst Barium halide promoters Active oxygen species Methyl halide intermediates 

分 类 号：TQ426[化学工程]