Electrochemically Driven Cation Exchange Enables the Rational Design of Active CO₂Reduction Electrocatalysts

Abstract

Metal oxides or sulfides are considered to be one of the most promising CO2 reduction reaction (CO2RR) precatalysts, owing to their electrochemical conversion in situ into highly active electrocatalytic species. However, further improvement of the performance requires new tools to gain fine control over the composition of the active species and its structural features [e.g., grain boundaries (GBs) and undercoordinated sites (USs)], directly from a predesigned template material. Herein, we describe a novel electrochemically driven cation exchange (ED‐CE) method that enables the conversion of a predesigned CoS2 template into a CO2RR catalyst, Cu2S. By means of ED‐CE, the final Cu2S catalyst inherits the original 3 D morphology of CoS2, and preserves its high density of GBs. Additionally, the catalyst's phase structure, composition, and density of USs were precisely tuned, thus enabling rational design of active CO2RR sites. The obtained Cu2S catalyst achieved a CO2‐to‐formate Faradaic efficiency of over 87 % and a record high activity (among reported Cu‐based catalysts). Hence, this study opens the way for utilization of ED‐CE reactions to design advanced electrocatalysts.

Recent Progress in Electrocatalytic Methanation of CO2 at Ambient Conditions

“…[133] The formed biphasic catalyst coupled with inter-particle GBs and undercoordinated sites are the active sites and modulate the binding energies to the intermediates produced in CO 2 RR. [134] Though it was reported that Cu electrodes derived from the reduction of thick Cu 2 O films exhibit high FE toward CO and formate formation at low overpotentials, [135] the Cu particles with GB structures in the oxide-derived Cu catalysts possess strengthen binding sites for further hydrogenation of *CO into hydrocarbons. [136,137] However, some reports shows that oxidized Cu catalysts favor for electrochemical CO 2 RR to C 2 products, rather than to CH 4 .…”

An Investigation of Active Sites for electrochemical CO2 Reduction Reactions: From In Situ Characterization to Rational Design

“…Recently, Hod's group prepared a Cu 2 O@CoS x electrocatalyst using an electrochemically driven cation exchange method. [ 82 ] The rich grain boundaries and under‐coordinated sites acted as active species during CO 2 RR, exhibiting a CO 2 ‐to‐formate FE greater than 87%.…”

An Efficient Interfacial Synthesis of Two‐Dimensional Metal–Organic Framework Nanosheets for Electrochemical Hydrogen Peroxide Production

“…Since the discovery of graphene in 2004, two‐dimensional (2D) materials have been attracted huge research attentions due to their unique physical, optical and electrical properties so as to many highly promising applications [1] . Apart from extensively investigated 2D materials such as g‐C 3 N 4 , layered double hydroxides (LDH), transition‐metal dichalcogenides (TMDs), and hexagonal boron nitride (h‐BN), [2–5] the 2D metal–organic frameworks (MOFs) comprised of metal centers and organic linkers have aroused emerging interests in materials and catalysis [6–13] . Because of their extraordinarily high surface areas, tunable pore size and regulable internal surface, MOFs have been widely applied in many fields, such as electrocatalysis [14–17] .…”

“…[1] Apart from extensively investigated 2D materials such as g-C 3 N 4 , layered double hydroxides (LDH), transition-metal dichalcogenides (TMDs), and hexagonal boron nitride (h-BN), [2][3][4][5] the 2D metal-organic frameworks (MOFs) comprised of metal centers and organic linkers have aroused emerging interests in materials and catalysis. [6][7][8][9][10][11][12][13] Because of their extraordinarily high surface areas, tunable pore size and regulable internal surface, MOFs have been widely applied in many fields, such as electrocatalysis. [14][15][16][17] To date, the most reported method for synthesizing 2D MOF NSs was ultrasonication and solvo-thermal method.…”