Copper/Carbon Heterogenous Interfaces for Enhanced Selective Electrocatalytic Reduction of CO₂ to Formate

Abstract

bismuth-, [5,7] and tin-based [8] electrodes, the low abundance and uneven distribution of the respective elements result in a high cost. Cu is an Earth abundant element and has a considerably lower price. [9] Recent studies revealed that formate could be generated over metallic Cu catalysts via CO 2 RR, while it is always accompanied by the production of other products. To improve the performance of Cu-based catalyst for formate production, an effective approach was to design Cu-based heterostructures. [10] Cu-Au bimetallic catalyst showed an outstanding formate Faradaic efficiency (FE) of 81% and a formate current density (j formate ) of 10.4 mA cm −2 for formate at −0.6 V versus reversible hydrogen electrode (RHE). [11] Wang et al. reported a CuS/Cu 2 O catalyst which exhibited FE of 67.6% for formate production with current density of 15.3 mA cm −2 at the given potential −0.9 V versus RHE. [9] On cobaltdecorated Cu thin films, formate could be formed with FE of 80% and the current density of 1.1 mA cm −2 at −0.65 V versus RHE. [12] Carbon-supported copper catalysts also were used to produce formate via CO 2 RR, [3,13] and it has been well known that electrocatalytic performance not only depends on the morphologic and structural characteristics of metal particles, but also the properties of the carbon substrates. Metal-organic frameworks (MOFs) are one of the attractive carbon precursors which have been widely used to fabricate the hybrid catalysts containing metal (oxides) nanoparticles and porous carbon materials. MOF-derived Cu 2 O/Cu nanospheres anchored in nitrogen-doped hollow porous carbon hybrid composites (Cu 2 O/ Cu@NC) exhibited FE of 70.5% for formate production with current density of below 10 mA cm −2 at −0.68 V versus RHE. [14] Yang et al. presented a catalyst of Cu nanoparticles embedded in carbon substrate for CO 2 RR to formate with FE of 78% and current density of 6 mA cm −2 at −1.2 V versus RHE. [15] In spite of these impressive efforts, the current density of CO 2 to formate over Cu-based catalysts is always very low. A current density of 65.8 mA cm −2 at −1.8 V versus Ag/Ag + was observed with an FE to formic acid of 90.5% over MOFs-decorated Cu cathode in the electrolytes containing ionic liquid, organic solvent, and H 2 O. [16] However, the utilization of organic solvent and ionic liquid increases the preparation cost, and the volatilization of acetonitrile may lead to the loss of electrolyte. Therefore, developing a Cu-based electrocatalyst with high formate selectivity and activity under the aqueous media remains a great challenge.Herein, we developed a hybrid composite electrocatalyst including Cu 2 O, Cu, and nitrogen-doped carbon (HCS/Cu), Electrochemical reduction of CO 2 (CO 2 RR) to formate is a promising route to prepare value-added chemical. Developing low-cost and efficient electrocatalysts with high product selectivity is still a grand challenge. Herein, a novel Cu anchored on hollow carbon spheres catalysts (HCS/Cu-x, x represents the mass of CuCl 2 added in the system) ...

Facet Dopant Regulation of Cu2O Boosts Electrocatalytic CO2 Reduction to Formate

“…d) FE HCOO − of advanced Cu‐based CO 2 RR catalysts. (Cu foam, [ 22 ] P4VP‐modified Cu, [ 23 ] HOD‐CuO, [ 24 ] Cu 2 O/CuS, [ 14b ] Cu fiber felt, [ 25 ] Cu 2 O/Cu@NC‐800, [ 26 ] CuS x , [ 14a ] Cu‐Au bimetallic, [ 27 ] CuS/N,S‐rGO, [ 28 ] HCS/Cu‐0.12, [ 29 ] and this work). e) Stability test of S3‐Cu 2 O‐70 at −0.9 V RHE in 0.1 m KHCO 3 electrolyte.…”

Reconstructing Cu Nanoparticle Supported on Vertical Graphene Surfaces via Electrochemical Treatment to Tune the Selectivity of CO2 Reduction toward Valuable Products

“…In contrast, formate was the dominant product over the ET-L catalyst under every applied potential, achieving the highest FE formate of ∼77.2% at −1.0 V RHE . This suggested that the ET-L catalyst was among the best formate-selective Cu-based catalysts. , Though ET-L was able to produce C2+ products from −1.2 to −1.4 V RHE , the suppressed FE C2+ suggested that its reaction pathway to C2+ products was not preferred. As a control, the VG without Cu was electrochemically treated using the same ROR treatment.…”

Electro‐Synthesis of Organic Compounds with Heterogeneous Catalysis

“…Du et al have designed a new Cu‐anchored on hollow carbon sphere catalyst (HCS/Cu‐x, where x represents the mass of CuCl 2 added in the system), allowing for controllable Cu/C heterogeneous interfaces. [ 189 ] The optimized HCS/Cu‐0.12 catalyst with a rich Cu/C heterogeneous interface and hollow structure is advantageous to mass transmission. Wu and colleagues devised a novel core‐shell configuration for bimetallic alloy/oxide nanowire catalysts.…”