Engineering the Local Microenvironment over Bi Nanosheets for Highly Selective Electrocatalytic Conversion of CO₂ to HCOOH in Strong Acid

Abstract

The extensive deployment of the electrocatalytic CO 2 reduction reaction (CO 2 RR) is presently limited by the utilization of alkaline/neutral electrolytes in which carbonate formation severely reduces the carbon efficiency and electrolysis stability. By contrast, the CO 2 RR in a strong acid electrolyte can overcome these shortcomings, yet the hydrogen evolution reaction (HER) greatly outcompetes the CO 2 RR in acidic media. Herein, CO 2 reduction to HCOOH, a significant chemical intermediate in many industrial processes, was realized in strong acid (pH ≤ 1) through introducing K + cations into the electrolyte. The K + -assisted acidic CO 2 RR accordingly manufactured HCOOH with a high Faradaic efficiency of 92.2% @−1.23 V RHE and a commercially relevant current density of −237.1 mA cm −2 . More importantly, a high single-pass carbon efficiency of 27.4% for HCOOH production was demonstrated in acid, which exceeded the value obtained in the alkaline CO 2 RR. Further mechanistic studies demonstrated that K + can engineer the local microenvironment over the Bi catalyst surface by reducing the proton coverage to suppress the competing HER and creating local interaction to stabilize the *OCOH intermediate, which ultimately promotes high-efficiency CO 2 conversion to HCOOH in strong acidic media.

Enhanced electrocatalytic reduction of CO2to formateviadoping Ce in Bi2O3nanosheets

“…However, various Bi-based electrocatalysts usually suffer from undesirable activity with a narrow potential window of high selectivity, a low current density for the formation of formate and relatively poor selectivity for formate production. 15,20,[24][25][26][27][28] Up to now, a lot of effort has been devoted to improving the ECR performance of Bi-based electrocatalysts, such as tuning the size, 29 controlling the morphology, [25][26][27][28]30,31 and heterostructure engineering. [32][33][34][35][36] Among these strategies, element doping to regulate the electronic structure of catalysts has been regarded as a powerful way to enhance the activity of ECR.…”

Metal–Organic Framework-Derived BiIn Bimetallic Oxide Nanoparticles Embedded in Carbon Networks for Efficient Electrochemical Reduction of CO2 to Formate

“…In order to obtain accurate results, quantitative sampling was repeated twice, and each sampling time was 30 min. The Faradaic efficiency of the gas product is calculated as eq . , where n in the formula represents the number of transferred electrons ( n = 2), g (mL min –1 ) represents the gas flow rate of CO 2 entering the H-type electrolytic cell, and the CO concentration detected by GC is represented by x . i is the total current measured during gas collection.…”

“…P-region transition metals such as Pd, Sn, , Bi, , Pb, and In , exhibit high formate selectivity in the electrochemical reduction of CO 2 . Especially, bismuth-based catalysts (Bi 2 O 3 , , Bi, etc.)…”

High Efficient Catalyst of N‐doped Carbon Modified Copper Containing Rich Cu−N−C Active Sites for Electrocatalytic CO2 Reduction

“…The conversion of CO 2 to the target products can be effectively realized by selecting electrocatalytic materials. Copper and copper‐based materials have been widely studied as CO 2 RR catalysts, which can electrocatalyze CO 2 to produce C 1 products such as CO and formic acid, and C 2 products such as ethanol and ethylene [7–9] . However, the catalytic mechanism of C 2 products has not been clarified so far.…”

“…Copper and copper-based materials have been widely studied as CO 2 RR catalysts, which can electrocatalyze CO 2 to produce C 1 products such as CO and formic acid, and C 2 products such as ethanol and ethylene. [7][8][9] However, the catalytic mechanism of C 2 products has not been clarified so far. Koper et al [10] calculated the hydrogen electrode model and found that two CO molecules were coupled on the Cu (100) crystal plane and formed *C 2 O 2 with electron transfer.…”