Efficient CO₂ Electroreduction with a Monolayer Bi₂WO₆ through a Metallic Intermediate Surface State

Abstract

Electrocatalytic conversion of carbon dioxide to high-value fuels and chemical feedstocks represents a promising solution toward carbon neutrality. Ongoing efforts have been directed to the development of high-performance, mass production, and cost-efficient catalysts, which, in turn, requires a more precise understanding of the operando details of the catalytic interface and fine control over the reaction pathway. Here, we report that a two-dimensional (2D) monolayer Bi2WO6 with high bismuth exposure demonstrates excellent performance for the electrocatalytic conversion of CO2 to formic acid, including the high Faradic efficiency (FE) over a broad potential range (over 90% from 0.9 to 1.3 V vs RHE, >98% FE at 1.0 V vs RHE) and a high current density over 250 mA/cm2 in a flow cell equipped with a gas diffusion electrode (>97% FE). The distinct reaction pathway observed in the electrocatalytic process, in contrast to the photocatalytic reactions, was investigated by density functional theory. Additionally, the mechanistic investigation further elucidates in operando phase transition to a “metallic intermediate state” on monolayer Bi2WO6 during the electrocatalytic process, providing the experimental evidence to the basis of satisfying performance from all Bi-based catalysts in CO2 reduction.

W4PCl11monolayer: an unexplored 2D material with moderate direct bandgap and strong visible-light absorption for highly efficient solar cells

“…In experiment, 2D Bi 2 WO 6 monolayer have been successfully synthesized and applied to photocatalytic field recently. 67,68 The previous works show that 2D Bi 2 WO 6 monolayer is an indirect semiconductor with the bandgap of 2.76 eV at the HSE06 level and the CBM and VBM of Bi 2 WO 6 monolayer deducted by the vacuum energy level are −4.63 and −7.39 eV, respectively, matching those of W 4 PCl 11 monolayer with the typical band alignment of type-II heterostructure. 13,66 Thus, as shown in Fig.…”

Metal-induced oxygen vacancies on Bi2WO6 for efficient CO2 photoreduction

“…It can be seen from Fig. 2c that the (200) interplanar spacing of BWO in the HRTEM image is 0.273 nm, and the interplanar spacing of Au particle is 0.231 nm [31][32][33]. Additionally, the elemental mapping images (Fig.…”

The Critical Role of Initial/Operando Oxygen Loading in General Bismuth-Based Catalysts for Electroreduction of Carbon Dioxide

“…15,16 Notably, although satisfying high Faraday efficiencies (FEs) and current densities have been achieved in the field of electrocatalytic carbon dioxide reduction to formic acid with bismuth-based materials, it is still difficult to clarify the universal determining factor (if any) for the performance of whole bismuth-based catalyst family, which is certainly beneficial to its ongoing development toward industrializa-tions. This task is made even more challenging considering the inevitable in situ structural/morphological reconstructions of the Bi-based catalysts in the electrochemical reduction of carbon dioxide under operando electrolysis conditions, 17,18 during which the phase transformation, the changes of valence state, local coordination environment, and electron-transfer behavior of catalysts all requires careful consideration. In addition to the precise in situ characterizations of the electrode materials, the correlation between these initial and operando states, if existing, is also of significant value to facilitate the advancing of future catalytic systems.…”

“…23,24 It has been recently revealed that nonmetal bismuth materials go through an in situ structure change during the electrocatalytic process, into a metallic meta-phase with close-to-zero valence state of Bi, while much of the solid evidence indicated that such an immediate metalloid bismuth is the actual active species. 17,25,26 It is therefore interesting to notice that the asprepared metal bismuth even shows inferior performance for carbon dioxide reduction compared to other bismuth compound derivatives in an aqueous solution. Two possible reasons could contribute to this phenomenon.…”

“…The Role of Initial/Operando Oxygen-Level in Bi-Based CO 2 RR Catalysts. Bi-based materials exhibited excellent performance in the reductive conversion of carbon dioxide to formic acid, as a result of the selective adsorption of formic acid intermediates (*HCO 2 ) on the bismuth surface. , It has been recently revealed that nonmetal bismuth materials go through an in situ structure change during the electrocatalytic process, into a metallic meta-phase with close-to-zero valence state of Bi, while much of the solid evidence indicated that such an immediate metalloid bismuth is the actual active species. ,, It is therefore interesting to notice that the as-prepared metal bismuth even shows inferior performance for carbon dioxide reduction compared to other bismuth compound derivatives in an aqueous solution. Two possible reasons could contribute to this phenomenon.…”