乙炔电还原制备乙烯的反应机理  

Reaction mechanism of electrochemical reduction of acetylene to ethylene

作　　者：宋秀丽[1,2] 贾瑞龙[1] 解学佳[1] 梁镇海[1] 朱珍平[3] 

机构地区：[1]太原理工大学化学化工学院,山西太原030024 [2]太原师范学院化学系,山西太原030031 [3]中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西太原030001

出　　处：《化工学报》2016年第4期1340-1347,共8页CIESC Journal

基　　金：国家自然科学基金委员会与神华集团有限责任公司联合资助项目(U1261103);中国科学院山西煤炭化学研究所煤转化国家重点实验室开放基金项目(J12-13-913)~~

摘　　要：选择钯电还原乙炔制备乙烯并通过气相色谱法对产品进行表征,利用第一性原理计算方法探讨乙炔在催化剂Pd(111)表面的吸附情况,采用循环伏安法研究钯电极在硫酸溶液中还原乙炔的电极过程,测定电极的稳态极化曲线并根据极化曲线推算Tafel斜率,重点结合表观传递系数及反应级数对拟定的乙炔电还原制备乙烯的反应机理进行验证。实验结果表明:乙炔分子在Pd(111)面上呈平行桥键构型时最稳定;钯电极在硫酸溶液中可将乙炔电还原为乙烯;得出了反应最可能的速率控制步骤。Electrochemical synthesis of ethylene from acetylene was put forward and the synthesized ethylene was characterized by gas chromatography（GC）. First-principle calculations were carried out to examine the adsorption of acetylene over the Pd（111） surface. The electrochemical reduction behavior of acetylene has been investigated on a Pd electrode by cyclic voltammetry（CV） and stable polarization curves in sulfuric acid. The formation mechanism of ethylene in the sulfuric acid was proposed and the transfer coefficients of the reaction were calculated. The results showed that the acetylene molecule tended to be adsorbed through the threefold parallel-bridge configuration that was computed to be the most stable because of its lowest adsorption energy. The rate-determining step in the electrolysis process has been obtained. The rate of this step obtained from the assumed process agreed well with the experiment results.

关 键 词：乙炔 乙烯 吸附 还原 电化学机理 第一性原理 速率控制步骤 

分 类 号：O643[理学—物理化学] O646[理学—化学]