Defect and Interface Engineering for Aqueous Electrocatalytic CO2 Reduction

Abstract

Electrocatalytic CO 2 reduction (ECR) with rationally designed electrocatalysts is a promising strategy to reduce CO 2 emission and produce value-added products. Reactive sites of heterogeneous catalysts usually lie on the surface and subsurface, which allow improvement of the catalytic property by engineering the surface atoms. Defects of an electrocatalyst, such as dopants, atom vacancies, and grain boundaries, have potential to enable unconventional adsorption behaviors and chemical activities of reactants on the catalyst surface, and selectively enhance the stability of specific intermediates and corresponding ECR pathways. Moreover, the interface between two different electrocatalyst components can also stabilize active surface catalytic sites and enable their synergetic effects. In this review, we summarize how surface defects and interface can be rationally designed and functioned in ECR catalysts, and how these atomic-level controlling approaches help to promote efficiency and selectivity. The challenges and prospects are also discussed to suggest the future designs of ECR catalysts.

Strategies in catalysts and electrolyzer design for electrochemical CO 2 reduction toward C 2+ products

“…The primary disadvantage of this H-type cell is the low CO 2 solubility in aqueous electrolyte, which is only 0.034 M under ambient conditions, leading to limited CO 2 reduction current densities of j < 100 mA cm −2 (64). Moreover, other intrinsic drawbacks, including a limited electrode surface area and a large interelectrode distance, have failed to meet the growing research requirements (105,106). For C 2+ product generation, H-type cells usually show low selectivity under high overpotentials, e.g., 32% for ethylene at −0.98 V versus RHE (107), 13.1% for n-propanol at −0.9 V versus RHE (99), and 20.4% for ethanol at −0.46 V versus RHE (108), due to the seriously competitive hydrogen evolution.…”

Two‐Dimensional Electrocatalysts for Efficient Reduction of Carbon Dioxide

“…Both experimental and theoretical investigations have confirmed that the structural properties surveyed in the next subsections account for most of the unique catalytic properties of 2D materials …”

“…It is a chemically inert molecule with two strong C=O double bonds, each with a bond energy of about 805 kJ mol −1 . In the eCO 2 RR, there is a significant activation energy barrier associated with the initial one‐electron reduction of CO 2 to form the CO 2 .− radical anion due to a large structural change . Consequently, this process occurs at a highly negative potential on a noncatalytic electrode, with a standard reduction potential of −1.97 V vs. the standard hydrogen electrode (SHE) in dimethylformamide (DMF) or −1.90 V vs. SHE in water at room temperature .…”

Stepping towards Solar Water Splitting: Recent Progress in Bismuth Vanadate Photoanodes

“…Defect engineering, such as introduction of disorder and vacancy, can also be considered as a kind of self‐doping, which has been widely studied and reported in energy conversion applications . A typical case of defect doping is the hydrogenated treatment of TiO 2 to expand the photon absorption range from ultra‐violet to near‐infrared by creating a disordered surface and Ti 3+ self‐doping .…”