In Situ Engineering of the Cu⁺/Cu⁰ Interface to Boost C₂₊ Selectivity in CO₂ Electroreduction

Abstract

The Cu+/Cu0 interface in the Cu-based electrocatalyst is essential to promote the electrochemical reduction of carbon dioxide (ERCO2) to produce multi-carbon hydrocarbons and alcohols with high selectivity. However, due to the high activity of the Cu+/Cu0 interface, it is easy to be oxidized in the air. How to control and prepare a Cu-based electrocatalyst with an abundant and stable Cu+/Cu0 interface in situ is a huge challenge. Here, combined with density functional theory (DFT) calculations and experimental studies, we found that the trace halide ions adsorbed on Cu2O can slow the reduction kinetics of Cu+ → Cu0, which allowed us to in-situ well control the synthesis of the CuO-derived electrocatalyst with rich Cu+/Cu0 interfaces. Our Cu catalyst with a rich Cu+/Cu0 interface exhibits excellent ERCO2 performance. Under the operation potential of −0.98 V versus RHE, the Faraday efficiency of C2H4 and C2+ products are 55.8 and 75.7%, respectively, which is about 16% higher than that of CuO-derived electrocatalysts that do not use halide ions. The high comes from the improvement of the coupling efficiency of reaction intermediates such as CO–CO, which is proved by DFT calculations, and the suppression of hydrogen evolution reaction. Therefore, we provide an in-situ engineering strategy, which is simple and effective for the design and preparation of high-performance ERCO2 catalysts.

Operando Studies for CO2/CO Reduction in Flow‐Based Devices

“…The interface between Cu 0 and Cu + in the context of CO 2 RR has emerged as a pivotal factor significantly enhancing both the selectivity and stability of end products [88] . Another type of metal oxide‐derived material, characterized by rich nanograin‐boundary and denoted as Cu 2 O(CO), was prepared through a thermally reducing Cu 2 O nanocubes within a CO atmosphere.…”

Modification of Cu–ZnO–ZrO2 catalysts with La2O3 to quantitatively tune Cu+–Cu0 dual sites for hydrogenation of dimethyl adipate to produce 1,6-hexanediol

“…44 The Cu + / (Cu + + Cu 0 ) ratios were calculated. [45][46][47] And the X(Cu + ) values for CZZ-L0-CP, CZZ-L1-CP, CZZ-L2-CP, CZZ-L4-CP and CZZ-L6-CP were 37.3%, 43.7%, 50.0%, 52.8% and 53.1%, respectively (Table S6 †). Combined with the XPS and TPR characterization results, it can be seen that the added La prevents further reduction of Cu 2 O.…”

Nanograin-Boundary-Abundant Cu2O-Cu Nanocubes with High C2+ Selectivity and Good Stability during Electrochemical CO2 Reduction at a Current Density of 500 mA/cm2

“…Thus, an in-depth understanding of the structure evolution of the Cu-based catalysts under realistic CO 2 RR conditions is imperative, including the formation and stabilization of Cu 0 /Cu + interfaces. Over the past decade, many strategiessuch as plasma treatment, dopant modification, halogen adsorption, vacancy steering, surface modification with organic molecules, and structure confinement effects , have been used to create abundant nanograin boundaries and Cu 0 /Cu + interfacial sites on Cu-based catalysts. For example, Cuenya and co-workers synthesized a superior Cu catalyst using plasma treatment which gave rise to stable oxide layers and achieved a high FE of ethylene (60%) at a potential of −0.9 V versus the reversible hydrogen electrode (RHE) .…”

“…Cuprous oxide (Cu 2 O) is more resistant to electrochemical reduction than cupric oxide (CuO) at negative potentials . Cu 2 O nanomaterials therefore represent an ideal platform for creating Cu catalysts with abundant nanograin boundaries and Cu 0 /Cu + interfaces for CO 2 RR. ,, However, under high polarization and high current densities, the structural evolution from pristine Cu 2 O to Cu 0 occurs very rapidly, leading to dendritic Cu nanostructures that show a strong HER reaction . Therefore, designing and preparing Cu catalysts with abundant and stable nanograin boundaries and Cu 0 /Cu + interfaces is critical to the implementation of the CO 2 RR to C 2+ products on an industrial scale.…”