Scalable Chemical Interface Confinement Reduction BiOBr to Bismuth Porous Nanosheets for Electroreduction of Carbon Dioxide to Liquid Fuel

Abstract

Electrochemical reduction of carbon dioxide (CO2) toward chemical and fuel production is a compelling component of the new energy system. Two‐dimensional bismuth with a particular surface has been identified as a highly efficient electrocatalyst for converting CO2 to formate. However, the development of a controllable synthetic strategy for possible large‐scale production of such Bi materials remains highly challenging. Herein, a scalable chemical interface confinement reduction method is proposed for topotactic transformation of BiOBr (001) nanosheets to metallic Bi (001) porous nanosheets (PNS). As expected, the Bi (001) PNS exhibits excellent electrochemical performance on CO2 reduction to formate, with Faradaic efficiency of 95.2% and formate partial current density of 72 mA cm−2. Density functional theory calculations suggest that Bi PNS selectively exposes (001) surfaces with small‐angle grain boundaries can significantly lower the free energy barrier for the formation of *OCHO, which are responsible for the high activity and selectivity toward CO2‐to‐formate conversion.

Fabrication of 2D/2D BiOBr/g-C3N4 with efficient photocatalytic activity and clarification of its mechanism

“…The distinctive lattice fringes with d = 0.277 nm correspond to the (110) planes, which are perpendicular to the (001) planes. 45 The 2D g-C 3 N 4 nanosheets possess flexible and amorphous structures (Fig. 3b).…”

Recent progress of Bi-based electrocatalysts for electrocatalytic CO2 reduction

“…67 By using BiOBr nanosheets with an exposed (001) surface as precursors, Fu et al successfully fabricated porous Bi nanosheets possessing the (001) surface with rich grain boundaries via topotactic transformation. 69 The porous Bi nanosheets showed a FE foramte of 95.2% at −1.4 V vs. RHE. DFT calculations explained that the excellent CO 2 RR performance originated from the grain boundary-containing (001) surface endowing lower adsorption energy to the intermediate *OCHO.…”

Galvanic‐Cell Deposition Enables the Exposure of Bismuth Grain Boundary for Efficient Electroreduction of Carbon Dioxide

“…[15] In this regard, numerous research efforts have been devoted to tailoring the nanoarchitectures, morphologies, compositions, and defects of Bi-based catalysts toward efficient and stable electroreduction of CO 2 into formate. [8,[16][17][18][19][20][21][22][23] Despite the great achievements, the complicated synthetic routes and/or modest performance restrict the practical applications. Therefore, breakthroughs are still desirable to develop scalable and facile methods for direct synthesis of active Bi electrocatalysts.It has been well recognized that grain boundary can optimize electrocatalytic CO 2 activity and selectivity by stabilizing reaction intermediates.…”

“…Due to its characteristics of low melting point and easy oxidation, the present strategies of incorporating grain boundaries into metallic Bi are mainly based on the (electro)-chemical transformation of Bi-based compounds. [22,26] Yet the effect of residual negative ions and oxides on the performance of CO 2 RR as well as the structural change of Bi nanostructures remains elusive, making it rather difficult to exclusively clarify the correlation between grain boundaries and enhanced CO 2 RR.Electrodeposition is a common approach for directly growing metal catalysts onto conductive substrates, which can assure efficient electron transfer, enhance the exposure of active sites and facilitate electrolyte access. [15] However, the reported Bibased electrocatalysts through the current/voltage-controlled deposition methods exhibit a relatively low current density Metallic bismuth (Bi) holds great promise in efficient conversion of carbon dioxide (CO 2 ) into formate, yet the complicated synthetic routes and unobtrusive performance hinder the practical application.…”

“…Due to its characteristics of low melting point and easy oxidation, the present strategies of incorporating grain boundaries into metallic Bi are mainly based on the (electro)-chemical transformation of Bi-based compounds. [22,26] Yet the effect of residual negative ions and oxides on the performance of CO 2 RR as well as the structural change of Bi nanostructures remains elusive, making it rather difficult to exclusively clarify the correlation between grain boundaries and enhanced CO 2 RR.…”