Volume 210, 2018

Ligament size-dependent electrocatalytic activity of nanoporous Ag network for CO2 reduction

Abstract

Electrochemical CO2 reduction (ECR) depends significantly on the nanostructures of electrocatalysts. Here we show a nanoporous Ag network catalyst (np-Ag) for efficient electrochemical reduction of CO2. The np-Ag samples with an average ligament size of 21 nm (denoted by np-Ag (21 nm)) and 87 nm (denoted by np-Ag (87 nm)) were fabricated by dealloying the rapidly solidified Mg80Ag20 (wt%) alloy ribbons in 1 wt% citric acid and 5 wt% phosphoric acid, respectively. The ligament size effect on the electrocatalytic activity and selectivity of CO2 conversion into CO is investigated. When catalysing CO2 reduction in 0.1 M KHCO3, the np-Ag (21 nm) catalyst exhibits a significantly enhanced selectivity with a faradaic efficiency for CO formation of 85.0% at −0.8 V versus RHE, about two times that (41.2%) over the np-Ag (87 nm). Additionally, a superior catalytic activity is also achieved over the np-Ag (21 nm), with a >2.5-fold increase in the CO partial current density relative to the np-Ag (87 nm). The improved selectivity and activity of np-Ag (21 nm) are attributed to the enhanced electrochemical surface area, higher local pH derived from ligament size effect, as well as more defect sites (i.e., grain boundaries) in ligaments.

Graphical abstract: Ligament size-dependent electrocatalytic activity of nanoporous Ag network for CO2 reduction

Associated articles

Supplementary files

Article information

Article type
Paper
Submitted
05 Mar 2018
Accepted
16 Mar 2018
First published
17 Mar 2018

Faraday Discuss., 2018,210, 289-299

Ligament size-dependent electrocatalytic activity of nanoporous Ag network for CO2 reduction

W. Yang, W. Ma, Z. Zhang and C. Zhao, Faraday Discuss., 2018, 210, 289 DOI: 10.1039/C8FD00056E

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