Low-Crystallinity-Induced Lattice-Distorted Bismuth Nanosheets for Enhanced Electrocatalytic CO₂ Reduction to Formate

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical CO2 reduction to formate is key for carbon neutrality but faces challenges in activity and selectivity.
• Bismuth-based materials are promising electrocatalysts for CO2 reduction.

Purpose of the Study:

• To develop a crystallinity-mediated reconstruction strategy for engineering bismuth nanosheets with compressive strain.
• To enhance the efficiency and selectivity of the electrochemical CO2 reduction reaction (CO2RR) to formate.

Main Methods:

• Synthesized bismuth nanosheets (Bi NS-L and Bi NS-H) with varying crystallinity via electrochemical reduction of BOC precursors.
• Investigated the effect of compressive strain on CO2 adsorption and electrocatalytic performance.
• Coupled CO2RR with glycerol oxidation reaction (GOR) to reduce overall cell voltage.

Main Results:

• Lattice-distorted Bi NS-L, derived from low-crystallinity precursors, exhibited enhanced CO2 adsorption and activity.
• Bi NS-L achieved a formate Faradaic efficiency of 94.8% at -1.08 V vs RHE and a partial current density of 247.49 mA cm-2.
• Coupling CO2RR with GOR lowered the cell voltage to 2.3 V at 200 mA cm-2, producing 3965.6 μmol h-1 cm-2 formate.

Conclusions:

• Crystallinity-mediated reconstruction is an effective strategy to engineer compressive strain in bismuth nanosheets for efficient CO2 electroreduction.
• The engineered bismuth nanosheets demonstrate high activity and selectivity for formate production.
• Integrated electrocatalytic systems show potential for sustainable carbon utilization.