Carbon Nanogrid‐Directed Interfacial Electric Field Engineering Boosts Selective CO2‐to‐Formate Electrosynthesis

Why It Matters

The breakthrough demonstrates a scalable route to high‑efficiency, durable CO₂‑to‑formate electrolysis, addressing a key bottleneck for carbon‑neutral chemical manufacturing.

Key Takeaways

• Sn nanoparticles confined in carbon nanotube nanogrid.
• 95.6% formate FE at 300 mA cm⁻².
• Over 90% FE sustained 200 hours in alkaline flow cell.
• Enables 1.1 M formic acid production at 400 mA for 300 h.
• Interfacial electric field accelerates charge transport and suppresses HER.

Pulse Analysis

Electrochemical reduction of carbon dioxide to value‑added chemicals has long been hampered by the trade‑off between activity, selectivity, and durability. Conventional tin‑based catalysts suffer from poor electrical conductivity and rapid structural degradation when operated at industrially relevant current densities. Moreover, the competing hydrogen evolution reaction (HER) often erodes formate selectivity, limiting the economic viability of CO₂‑to‑formate processes. Addressing these challenges requires innovative catalyst designs that can manipulate the local reaction environment at the electrode interface.

The nanogrid‑directed interfacial electric field strategy leverages a three‑dimensional carbon nanotube (CNT) scaffold to spatially confine tin nanoparticles, creating a hierarchical Sn@CNT architecture. This configuration generates a confined electric field that redistributes charge density, accelerates electron transfer, and promotes water dissociation, thereby lowering the energy barrier for *HCOOH intermediate desorption. Operando spectroscopy confirms that the engineered field suppresses HER while enhancing CO₂ adsorption, delivering a remarkable 95.6% Faradaic efficiency for formate at 300 mA cm⁻². Stability tests show the catalyst maintains over 90% efficiency for 200 hours in alkaline flow cells and produces 1.1 M formic acid at 400 mA for more than 300 hours in solid‑electrolyte cells.

Beyond the immediate performance gains, this approach establishes a versatile design principle for electrochemical interfaces. By tuning the geometry and conductivity of nanogrid frameworks, researchers can tailor interfacial fields for a wide range of electrocatalytic reactions, from nitrogen reduction to oxygen evolution. The scalability of CNT‑based scaffolds and the low cost of tin make the technology attractive for commercial CO₂ utilization plants, potentially reducing the carbon footprint of chemical manufacturing while generating market‑grade formic acid. Future work will explore integration with renewable electricity sources and adaptation to other metal catalysts, paving the way for broader adoption of field‑engineered electrosynthesis.