In situ growth of Ag aerogels mediating effective electrocatalytic CO2 reduction and Zn-CO2 batteries

Abstract

Metal aerogels have outshined themselves in electrocatalysis, however, the brittle property has constrained their intrinsic activity by the traditional drop-coating method of electrode preparation. Herein, a rapid in-situ growth strategy to obtain porous Ag aerogels on conductive carbon cloth (Ag As/CC) working as free-standing electrode was designed for electrocatalytic CO2 reduction to CO. The preserved porous network structure of Ag aerogels with hydrophobic surface effectively inhibits the competing reaction of hydrogen evolution. The CO Faraday efficiency of 99.6%, mass activityCO of 23.33 mA mg−1, and Energy efficiencyCO of 59.85% were achieved at −1.0 V vs. RHE. Ag As/CC exhibits quick charge response ability with relaxation time constant of 0.04 s, and high mass transfer with Tafel slope of 59 mV dec−1. It also worked as the cathode to drive Zn-CO2 rechargeable battery with a peak power density of 2.16mW cm−2, to achieve electrocatalytic CO2 fixation and energy storage.