Electron‐Rich Bi Nanosheets Promote CO₂⋅⁻ Formation for High‐Performance and pH‐Universal Electrocatalytic CO₂ Reduction

Abstract

Electrochemical CO2 reduction reaction (CO2RR) to chemical fuels such as formate offers a promising pathway to carbon‐neutral future, but its practical application is largely inhibited by the lack of effective activation of CO2 molecules and pH‐universal feasibility. Here, we report an electronic structure manipulation strategy to electron‐rich Bi nanosheets, where electrons transfer from Cu donor to Bi acceptor in bimetallic Cu−Bi, enabling CO2RR towards formate with concurrent high activity, selectivity and stability in pH‐universal (acidic, neutral and alkaline) electrolytes. Combined in situ Raman spectra and computational calculations unravel that electron‐rich Bi promotes CO2⋅− formation to activate CO2 molecules, and enhance the adsorption strength of *OCHO intermediate with an up‐shifted p‐band center, thus leading to its superior activity and selectivity of formate. Further integration of the robust electron‐rich Bi nanosheets into III–V‐based photovoltaic solar cell results in an unassisted artificial leaf with a high solar‐to‐formate (STF) efficiency of 13.7 %.

Recent insights on the use of modified Zn-based catalysts in eCO2RR

“…The non-metal-based catalysts are mainly various carbon materials which include carbon fibers, graphene, carbon nanotubes (CNTs), and related modified carbon materials. 29 The metal-based catalysts are mainly divided into the following four categories according to their different products: (1) metals such as Ni, 30,31 Fe, 32 Pt 33 and Ti 34 are H-philic metals, which have relatively high HER potential and mainly cause the side reactions of HER; (2) Au, 35 Ag, 36 Zn, 37 Pd, 38 Ga 39 and other metals can strongly adsorb the *COOH intermediates, but the adsorption capacity for *CO intermediates is usually weak, therefore, the main product of eCO 2 RR is CO; (3) metal catalysts such as Pb, 40 In, 41 Sn, 42 Bi 43 and Cd 44 can effectively stabilize CO 2 − intermediates, can avoid CO 2 − intermediates being further reduced and can significantly promote the further electron-adding/proton-adding reaction of the CO 2 − intermediate on the catalyst surfaces, and the main product of eCO 2 RR is HCOOH; (4) the Cu-based catalysts can electrocatalytically reduce CO 2 to produce various C 1 , C 2 and C 3 products, 45 and in addition, by adjusting the chemical compositions, the surface structures or electrolyte contents of the catalyst, the product types and selectivity of the previously mentioned metal catalysts can be further adjusted.…”