Efficient electrosynthesis of high-purity carbon monoxide using “porous water” electrolyte

A research group has developed a new method for extracting high-purity carbon monoxide.

    High-purity carbon monoxide (CO) is a key raw material in the chemical industry, widely used in the preparation of phosgene and metal carbonyl compounds. Currently, CO production still relies primarily on fossil fuels and involves energy-intensive gas purification steps. Electrocatalytic CO₂ reduction (CO₂RR) is considered an ideal strategy for green CO synthesis. However, in practice, the electrolysis product often contains large amounts of unreacted CO₂ and impurities, resulting in high subsequent separation costs. Therefore, the direct synthesis of high-purity CO at low CO₂ concentrations has become a major challenge in the field of CO₂ electroreduction. This study proposes a novel strategy based on a “porous water” electrolyte, achieving efficient and stable synthesis of high-purity CO (97.0 wt%) in a low CO₂ concentration environment (15% CO₂), providing new insights for the resource utilization of CO₂.

Research Summary

    This study developed a novel electrolyte (Porous Electrolyte, PE) based on porous water. Dispersed zeolite nanocrystals (zeolite-NC) provide a stable microporous environment, enabling efficient adsorption and enrichment of CO₂ in the liquid phase. Under the action of an electric field, CO₂ is spontaneously released through an interfacial concentration gradient and efficiently converted to CO on a Ni-N/C electrocatalyst. This strategy avoids the traditional multi-step CO₂ capture-regeneration-electrolysis process, significantly improving the product purity of CO₂RR. At a current density of 150 mA cm⁻², CO purity remains above 90.0 wt% while significantly reducing energy consumption and costs. This method provides a new and efficient route for the electrosynthesis of high-purity CO₂.

Research Highlights

1. “Porous Water” Enhances CO₂ Adsorption and Increases Local Concentration
Zeolite nanocrystals provide permanent pores, allowing CO₂ to be physically adsorbed in the liquid phase and spontaneously desorbed under the action of an electric field, thereby increasing the interfacial CO₂ concentration.

2. Achieving High-Purity CO Electrosynthesis

Under a 15% CO₂ atmosphere, this strategy can directly synthesize 97.0 wt% pure CO₂, avoiding the separation issuescaused by unreacted CO₂ in traditional CO₂RR.

3. Low Energy Consumption and High Stability

Compared to traditional CO₂ regeneration-separation strategies, this method reduces energy consumption by 49.3% andcan operate stably for over 20 hours at 100 mA cm⁻², demonstrating excellent long-term stability.

4. Interfacial Electric Field Enhances Electron Transport and Accelerates Reaction Kinetics

The surface ion exchange interaction between K⁺ and Si-OH enhances the interfacial electric field, accelerating electrontransfer and thus enhancing the intrinsic activity of CO₂RR.