Three-dimensionally ordered macro-/mesoporous bismuth for efficient electrocatalytic CO₂ reduction to formate.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Bismuth (Bi)-based catalysts with nanoporous structures show promise for electrocatalytic reduction of carbon dioxide (CO2) to formate.
• Current methods for preparing nanoporous metallic Bi with controlled structures are challenging.
• Developing efficient catalysts is crucial for CO2 utilization and conversion.

Purpose of the Study:

• To controllably fabricate a three-dimensionally ordered macro-/mesoporous (3DM/m) bismuth catalyst.
• To investigate the catalytic performance of the 3DM/m Bi catalyst for CO2 electroreduction.
• To overcome the limitations of existing methods for preparing structured nanoporous Bi.

Main Methods:

• A hard-soft dual-template approach combined with a low-temperature wet-chemical reduction method.
• Utilized ammonia gas as an auxiliary reducing agent to facilitate the reduction of Bi3+ ions.
• Characterized the catalyst's structure and evaluated its electrochemical performance for CO2 reduction.

Main Results:

• Successfully fabricated a 3DM/m Bi catalyst with a well-defined hierarchical porous structure.
• Achieved a high formate faradaic efficiency of 95.6% at -0.9 V vs. the reversible hydrogen electrode (RHE).
• Demonstrated excellent formate selectivity (>85%) over a wide potential range (-0.8 V to -1.2 V vs. RHE).

Conclusions:

• The developed 3DM/m Bi catalyst offers a promising solution for efficient CO2 electroreduction to formate.
• The hierarchical porous architecture enhances catalytic activity by providing abundant active sites and facilitating mass transport.
• This method provides a new pathway for fabricating advanced nanoporous catalysts for electrochemical applications.