Defect-Driven Surface and Electronic Structure Modulation in Alloyed Bismuth Chalcogenide Nanosheets for CO₂...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Catalyst activity in electrochemical reactions is influenced by defects and edge site reactivity.
• The specific role of these factors in bismuth-based electrocatalysts for CO2RR remains underexplored.

Purpose of the Study:

• To investigate the impact of defects and edge sites on bismuth-based electrocatalysts for CO2RR.
• To synthesize and characterize Bi2Se3-xTex alloyed nanosheets with tunable defect concentrations.

Main Methods:

• Synthesis of Bi2Se3-xTex (x = 0, 1, 1.5, 2, 3) alloyed nanosheets.
• Characterization of surface morphology and electronic structure.
• Evaluation of CO2RR activity and Faradaic efficiency.
• Fabrication and testing of an integrated photoelectrochemical CO2RR device.

Main Results:

• Alloyed nanosheets exhibited rich defects and a high density of vertically aligned edges.
• Chalcogen vacancies introduced defect states, facilitating electron accumulation and lowering kinetic barriers for CO2RR.
• Achieved high Faradaic efficiency for formate production.
• The integrated photoelectrochemical device showed an applied bias photon-to-current efficiency of up to 12.1% for formate over 50 hours.

Conclusions:

• Defect engineering in Bi2Se3-xTex alloys effectively regulates CO2RR activity.
• Alloying provides a viable strategy for designing high-performance CO2RR catalysts.
• The study offers insights into optimizing bismuth-based electrocatalysts through controlled defect formation.