纳米泡沫银用于流动池电催化还原CO_(2)

Electrocatalytic Reduction of CO_(2) by Nano Silver Foams in the Flow Cell

纳米泡沫银(AgNFs)具有疏松多孔的内部结构,这种结构利于CO_(2)气体的传递,非常适合应用于流动池电催化体系。首先通过化学还原法制备了乙酸银前驱体,然后进行电化学还原制得AgNFs催化剂。进一步研究了不同CO_(2)流量、不同催化层厚度和不同pH电解质对AgNFs催化CO_(2)还原性能的影响,结果表明AgNFs在CO_(2)流量大于5 mL/min、催化层厚度为52.3μm、电解质为0.5 mol/L KOH时具有更好的催化活性和CO选择性,在电流密度-20~-80 mA/cm^(2)范围内,CO的法拉第效率(FECO)始终大于99%。在70 h的稳定性测试中,FECO稳定在93%以上。AgNFs的多孔结构能促进更多反应活性位点的暴露,利于CO_(2)的传质扩散,这是AgNFs在流动池中CO_(2)电催化还原性能好的主要原因。

Nano silver foams(AgNFs)possess a loose and porous internal structure,making it conducive to the transfer of CO_(2) gas and highly suitable for application in the electrocatalytic systems of a flow cell.Herein,silver acetate precursor was prepared using the chemical reduction method,and then AgNFs catalyst was obtained through electrochemical reduction.Additionally,the effects of different CO_(2) flow rates,different catalytic layer thickness and pH electrolyte on the catalytic performance of AgNFs for CO_(2) reduction were investigated.The results indicated that AgNFs exhibited superior catalytic activity and CO selectivity when the CO_(2) flow rate was greater than 5 mL/min,the catalytic layer thickness was 52.3μm and the electrolyte was 0.5 mol/L KOH.The Faraday efficiency of CO(FE CO)remained greater than 99%in the range of-20~-80 mA/cm^(2).During the 70 h stability test,the FE CO was stable at more than 93%.The good electrocatalytic reduction performance of AgNFs in the flow cell is mainly attributed to the porous structure of AgNFs,which promotes the exposure of more reactive sites and facilitates the mass transfer and diffusion of CO_(2).