Hydrangea-like Superstructured Micro/Nanoreactor of Topotactically Converted Ultrathin Bismuth Nanosheets for Highly Active CO₂ Electroreduction to Formate

Abstract

An electrocatalytic carbon dioxide reduction reaction (CO 2 RR) is an appealing route to obtain the valueadded feedstocks and alleviate the energy crisis. However, how to achieve high-performance electrocatalysts for CO 2 reduction to formate is challenging owing to the poor intrinsic activity, insufficient conductivity, and low surface density of active sites. Herein, we fabricated an extremely active and selective hydrangealike superstructured micro/nanoreactor of ultrathin bismuth nanosheets through an in situ electrochemical topotactic transformation of hierarchical bismuth oxide formate (BiOCOOH). The resulted bismuth nanosheet superstructure is in the form of three-dimensional intercrossed networks of ultrathin nanosheets, forming an ordered open porous structure through self-assembly, which can be used as a micro/nanoreactor to enable a large electrochemically active surface area as well as high atomic utilization. Such a distinctive nanostructure endows the material with high electrocatalytic performances for CO 2 reduction to formate with near-unity Faradaic selectivity (>95%) in a wide potential window from −0.78 to −1.18 V. Furthermore, this micro/nanoreactor can give the high current densities over 300 mA cm −2 at low applied potentials without compromising selectivity in a flow cell reactor. Density functional theory (DFT) and in situ attenuated total reflection-infrared spectroscopy (in situ ATR-IR) were further conducted to interpret the CO 2 RR mechanisms.

Recent progress of Bi-based electrocatalysts for electrocatalytic CO2 reduction

“…Most recently, Peng et al initially made bismuth oxide with hydrangea-like shapes as a Bi nanosheet precursor, followed by converting it into ultrathin Bi nanosheets using topotactic transformation. 71 As expected, the ultrathin Bi nanosheets exhibited an outstanding FE foramte selectivity (∼96%) in a broad range of overpotentials (from −0.78 V to −1.18 V vs. RHE). The above examples suggest that the precursor determines the finial morphology, fashion, geometry and physicochemical properties of Bi electrocatalysts, therefore attention should be paid to precursor synthesis, design, composition and selection in future studies.…”

Aligned InS Nanorods for Efficient Electrocatalytic Carbon Dioxide Reduction

“…The electrocatalytic carbon dioxide reduction reaction (CO 2 RR) powered by renewable sources is regarded as a promising route to achieve energy sustainability and reduce the greenhouse effect. − However, the process of CO 2 electroreduction involved a complex reaction path, leading to poor selectivity for chemical products . Among them, formate (or formic acid) is the most common liquid product of CO 2 reduction, which involved only two-electron transfer reaction paths. , In addition, as a safe and convenient liquid fuel, formic acid is not only an important intermediate in industrial reactions but also widely used in hydrogen energy storage and formic acid fuel cells. , However, electrochemical carbon dioxide reduction to formate currently faces great challenges, including slow reaction kinetics, low selectivity of target products, and competitive hydrogen eolution reaction (HER) . Therefore, the development of electrocatalysts with high activity, selectivity, and stability for the CO 2 RR is the key to the large-scale application of electrochemical carbon dioxide reduction to formate technology.…”

“…1 Among them, formate (or formic acid) is the most common liquid product of CO 2 reduction, which involved only two-electron transfer reaction paths. 2,5 In addition, as a safe and convenient liquid fuel, formic acid is not only an important intermediate in industrial reactions but also widely used in hydrogen energy storage and formic acid fuel cells. 6,7 However, electrochemical carbon dioxide reduction to formate currently faces great challenges, including slow reaction kinetics, low selectivity of target products, and competitive hydrogen eolution reaction (HER).…”

Electrospun one-dimensional electrocatalysts for boosting electrocatalysis

“…The electrochemical reduction of CO 2 to value-added products is a highly appreciated strategy for alleviating the greenhouse effect and energy crisis. 88 However, the multipleelectron transfer process leads to sluggish reaction kinetics for CO 2 reduction. 89 In addition, the competitive HER also CrystEngComm Highlight hinders the application of CO 2 reduction.…”