Anchored silver-palladium aerogel on carbon cloth via diazonium chemistry for electrochemical reduction of CO2.

[Display omitted] • New approach to engineering surface-bound catalysts via diazonium chemistry. • eCO 2 RR using a surface-anchored Ag-Pd aerogel on carbon cloth. • Cost-effective, simple, stable, efficient method for electrode surface modification. • First report of eCO 2 RR utilizing electro-grafted surface of CC with catalyst. Electrochemical CO 2 reduction reaction (eCO 2 RR) is a promising route for removal of CO 2 from the atmosphere and transforming it into value-added products. The development of new and efficient catalysts plays a vital role in this regard. Here a combination of carbon grafting and bimetallic metal aerogel is presented as a catalyst for eCO 2 RR. The grafted surface plays an essential function in assembling the catalyst on the carbon cloth (CC) surface as a supported catalyst. Herein, we describe the use of para -aminothiophenol (p-TP) as a grafting agent combined with diazonium chemistry to fix a metallic aerogel catalyst on CC as support. The silver, palladium and bi-metallic silver-palladium aerogels (Ag- p-TP , Pd- p-TP , and AgPd- p-TP) anchored onto the surface of CC yielding the corresponding surface-bound materials were used for testing the electrochemical reduction of CO 2. The mono-metallic Ag carbon cloth (Ag- p-TP /CC) exhibited the ability in reducing CO 2 to CO with moderate Faradaic efficiency (FE) of 74 % in 0.1 M, NaHCO 3 electrolyte at p H = 7.5. The bimetallic AgPd- p-TP -CC further enhanced the Faradaic efficiency for CO formation to 88.7 %, with an unexpectedly low onset potential of −0.09 V vs. RHE. Surprisingly, formate was identified to be the liquid product when Pd- p-TP -CC and AgPd- p-TP -CC were used, with maximal FE formate of 19.0 % and 25.7 % at −1.0 V vs. RHE, respectively. In contrast, CC lacking the chemical grafting that allows immobilization of the metal aerogel (Ag-Pd/CC) exhibits lower FEco% for eCO 2 RR, highlighting the importance of this chemical modification of the carbon cloth surface. Diazonium chemistry coupled with metal aerogels is a new approach to generating surface-bound catalysts for the effective reduction of CO 2. [ABSTRACT FROM AUTHOR]