Block Copolymer Particle‐Templated Cavitated Carbons Achieve Local Alkalinity for Enhancing Acidic Electrochemical CO2 Reduction

Why It Matters

Enabling efficient CO₂ electroreduction in acidic media sidesteps carbonate precipitation, raising overall carbon‑utilization efficiency and advancing scalable CO₂‑to‑fuel technologies.

Key Takeaways

• Cavitated carbon particles create ~130 nm cavities.
• Cavities generate local OH⁻, raising pH near catalyst.
• Au/CCP boosts CO production, suppresses H₂ evolution at pH 2.
• Performance exceeds solid carbon-supported Au catalyst.
• Binder and cation tuning further optimizes selectivity.

Pulse Analysis

Acidic electrochemical CO₂ reduction has long been hampered by the hydrogen evolution reaction, which dominates when protons are abundant. Conventional neutral or alkaline electrolytes avoid this issue but suffer from carbonate formation that wastes CO₂ feedstock. By engineering a nanostructured carbon support with internal cavities, the research team creates a confined micro‑environment where OH⁻ ions accumulate, effectively raising the local pH while the bulk remains strongly acidic. This strategy reconciles the competing demands of low carbonate buildup and high CO₂RR selectivity.

The cavitated carbon particles are fabricated through block‑copolymer templating, producing a uniform network of ~130 nm pores. Gold nanoparticles deposited on this scaffold (5 wt.% Au/CCP) exhibit markedly higher faradaic efficiency for CO production compared with a solid‑carbon counterpart (Au/SCP) that lacks cavities. Flow‑cell measurements at pH 2 show CO selectivity exceeding 80 % and a substantial reduction in H₂ evolution. Complementary multiphysics simulations reveal that the confined geometry concentrates hydroxide ions, generating a localized alkaline zone that suppresses proton reduction. Adjustments to binder chemistry, cation type, and concentration further fine‑tune the microenvironment, demonstrating the versatility of the approach.

The implications extend beyond laboratory proof‑of‑concept. Operating CO₂ electrolysis under acidic conditions eliminates the need for carbonate management, simplifying system design and reducing capital costs for large‑scale deployment. Moreover, the cavity‑confinement principle offers a modular toolkit for tailoring catalyst microenvironments across a range of electrocatalytic processes. As the industry seeks cost‑effective pathways to convert CO₂ into fuels and chemicals, such micro‑architectural innovations could accelerate commercialization and improve the overall carbon‑capture value chain.