Pd修饰Cu电极的电化学CO2还原

Electrochemical CO2 Reduction on Pd-Modified Cu Foil

利用微分电化学质谱和电化学原位衰减全反射红外光谱技术探究了Cu和CuPd催化剂上CO2和CO的电化学还原行为.红外光谱观察到了生成甲醇、甲烷与乙烯的CHx中间物种.在CuPd电极CO2还原过程中,红外光谱的CO吸附峰起始电位比Cu正移大约300 mV,说明CuPd能够有效促进CO2还原;CO饱和溶液中,Cu和CuPd电极CO起始吸附电位基本相同;两电极上CO谱带出现的电位与CO3^2-的谱带降低的电位基本相同,说明C O的吸附需要CO3^2-的脱附.利用电化学在线质谱发现在CuPd电极上CO还原产生CH4和CH3OH的起始电位比Cu电极正移约200 mV.推测催化活性的提升可能是由于Pd的引入改变了Cu的d能带,且Pd吸附更多的H,从而促进CO2还原,使CO能够与H结合并被深度还原.

Bimetallic catalysts can improve CO2 reduction efficiency via the combined properties of two metals.CuPd shows enhanced CO2 reduction activity compared to copper alone.Using differential electrochemical mass spectrometry(DEMS)and electrochemical infrared(IR)spectroscopy,volatile products and adsorbed intermediates were measured during CO2 and CO reduction on Cu and CuPd.The IR band corresponding to adsorbed CO appears 300 mV more positive on CuPd than that on Cu,indicating acceleration of CO2 reduction to CO.Electrochemical IR spectroscopy measurements in CO-saturated solutions reveal similar potentials for CO adsorption and CO3^2-desorption on CuPd and Cu,indicating that CO adsorption is controlled by desorption of CO3^2-.DEMS measurements carried out during CO reduction at both electrodes showed that the onset potential for reduction of CO to CH4 and CH3OH on CuPd is about 200 mV more positive than that on Cu.We attribute these improvements to interaction of Cu and Pd,which shifts the d-band center of the Cu sites.