Electrodeposited AgCu Foam Catalysts for Enhanced Reduction of CO₂ to CO

Abstract

Selective electrochemical reduction of CO2 is an emerging field which needs more active and stable catalysts for its practicability. In this work, we have studied the influence of Ag metal incorporation into Cu dendritic structures on the product distribution and selectivity of CO2 electroreduction. Bimetallic AgCu foams prepared by hydrogen bubble templated electrodeposition shift the potentials of CO production to more positive values compared to bulk silver. The presence of Ag during the electrodeposition significantly changed the size and the shape of the dendrites in the pore walls of AgCu foams compared to Cu foam. The CO adsorption characteristics are studied by operando Raman spectroscopy. In the presence of Ag, the maximum CO adsorption is observed at a more positive potential. As a result, an improved selectivity for CO is obtained for AgCu foam catalysts at lower overpotentials compared to Cu foam catalyst, evidencing a synergistic effect between the bimetallic components. We were successful in increasing the CO mass activity with respect to the total Ag amount. AgCu foams are found to retain the CO selectivity during long-term operation, and with their easily scalable electrodeposition synthesis they possess high potential for industrial application.

Hydrogen Bubble Templated Metal Foams as Efficient Catalysts of CO2 Electroreduction

“…These metals belong, according to Winand's classification, to the group of normal or intermediate metals. A non‐exhaustive list includes pure metals such as Sn [66,67] Pb, [68] Zn, [69,70] Bi, [71] Ag [72–74] and Cu, [75–78] as well as bimetallic systems where Sn foams are deposited on Cu surfaces [79–84] or when smoothly dispersed Ag and Cu form one bimetallic foam structure [85,86] . In what follows, we summarize the DHBT‐assisted preparation strategies of these metal foams, as well as some important aspects of CO 2 reduction occurring on them.…”

“…The recipe of Najdovski et al [46] . was later applied by Kottakkat et al [85] . in order to create bimetallic Ag−Cu foams for purposes of CO 2 electroreduction.…”

Synergy between a Silver–Copper Surface Alloy Composition and Carbon Dioxide Adsorption and Activation

“…17 Recently, the silver-copper (AgCu) catalyst has demonstrated a dramatic improvement in product selectivity and activity compared to pure Cu catalyst. [18][19][20][21] However, the bimetal systems underlying CO2RR activation mechanism responsible for the enhanced catalytic performance remains unclear. Various reaction mechanisms have been suggested based on preconceived notions of the material properties and reaction mechanisms.…”

Metallic Porous Electrodes Enable Efficient Bicarbonate Electrolysis

“…13 The bicarbonate electrolysis experiments were designed to test modifications of the cathodes: silver foam (denoted as " Foam "); etched silver foam (denoted as " Foam/E "); and etched silver foam coated with silver nanowires (denoted as " Foam/nanowires ") ( Figure 2b). Silver was selected as the cathode of choice because it mediates effective conversion of CO 2 to CO. 31,32 The Foam samples (2 cm × 2 cm × 200 µm) were prepared by washing commercially available silver foams with deionized (DI)…”