The Controllable Reconstruction of Bi‐MOFs for Electrochemical CO₂ Reduction through Electrolyte and Potential Mediation

Abstract

Monitoring and controlling the reconstruction of materials under working conditions is crucial for the precise identification of active sites,e lucidation of reaction mechanisms,and rational design of advanced catalysts.Herein, aBibased metal-organic framework (Bi-MOF) for electrochemical CO 2 reduction is selected as ac ase study.I ns itu Raman spectra combined with ex situ electron microscopyr eveal that the intricate reconstruction of the Bi-MOF can be controlled using two steps:1 )electrolyte-mediated dissociation and conversion of Bi-MOF to Bi 2 O 2 CO 3 ,a nd 2) potential-mediated reduction of Bi 2 O 2 CO 3 to Bi. The intentionally reconstructed Bi catalyst exhibits excellent activity,selectivity,and durability for formate production, and the unsaturated surface Bi atoms formed during reconstruction become the active sites.T his work emphasizes the significant impact of pre-catalyst reconstruction under working conditions and provides insight into the design of highly active and stable electrocatalysts through the regulation of these processes.

Dynamic Evolution of Active Sites in Electrocatalytic CO2 Reduction Reaction: Fundamental Understanding and Recent Progress

“…Higher activity and lower CO selectivity for smaller particles Molecular catalysts CuPc [175] No catholyte Ex situ XPS and operando XAS Transition to metallic Cu with diverse coordination number CH 4 FE max of 62% when coordination number is 4.2 NNU-33(S) [176] 1 m KOH XRD, in situ XAS, and Raman Anion exchange of sulfate by hydroxyl moiety CH 4 FE increased from 55% to 82% after anion exchange HKUST-1 [144] 1 m KOH SEM, operando XAS Conversion to Cu cluster C 2 H 4 selectivity 45% Bi-MOFs [182] 0.1 m KHCO 3 In situ Raman, ex-situ TEM First conversion to Bi 2 O 2 CO 3 , then to metallic Bi Formate FE of 92% within 10 h FeF 20 TPP [195] 0.5 m NaHCO 3 Operando UV-vis and XAS Fe(III) conversion into Fe(II) first, then electron localization at the ligand is changed CO FE of 93% SACs Cu-N-C [177] 0.1 m CsHCO 3 Operando XAS Reversible conversion to metallic Cu…”

“…Own to the abundant unsaturated surface Bi atoms, the in situ constructed Bi catalysts behaved excellent performance toward formate production. [ 182 ]…”

Gadolinium Changes the Local Electron Densities of Nickel 3d Orbitals for Efficient Electrocatalytic CO2 Reduction

“…Electrochemical active surface areas (ECSAs) were measured through double‐layer capacitances ( C d1 ) based on cyclic voltammograms (Figure S10) [37, 38] . As shown in Figure 4d, CBNNiGd‐700 possesses a larger ECSA than CBNNi‐700, clarifying the superior electrocatalytic capability of the former.…”

“…Electrochemical active surface areas (ECSAs) were measured through double-layer capacitances (C d1 ) based on cyclic voltammograms (Figure S10). [37,38] As shown in Fig- ure 4d, CBNNiGd-700 possesses a larger ECSA than CBNNi-700, clarifying the superior electrocatalytic capability of the former. CBNNiGd-700 and CBNNi-700 have the similar specific surface areas (Table S1) and the CO 2 adsorption capacities (Figure S11), together with the virtually identical number of Ni I active sites on their surfaces (Table S2).…”

Toward High‐Performance CO2‐to‐C2 Electroreduction via Linker Tuning on MOF‐Derived Catalysts

“…Electrochemical reduction of CO 2 (eCO 2 RR) to achieve valueadded chemicals, especially C 2 products ethylene (C 2 H 4 ) [1,2] and ethanol (C 2 H 5 OH) [3] has been identified as the most potential solution to mitigate the greenhouse effect and the energy crisis. [4] As a kind of porous material, metal-organic frameworks (MOFs) have been extensively explored in eCO 2 RR due to their ordered structure, [5,6] high porosity, [7,8] adjustable chemical functionality, [9][10][11] and flexibility in the structure design. [10,12] Additionally, the structures of MOF catalysts are easy to be in situ reconstructed under electrochemical conditions to be derive to new structures, [2,13] which are commonly referred to as MOF-derived catalyst.…”