Chirong Sun  Muhammad Shakir Hussain  Sheraz Ahmed  Jaehoon Kim

Vol. 32,  No. 1, pp. 27-34, Mar.  2026
10.7464/ksct.2026.32.1.27

High pressure CO production Electrochemical CO2RR Carbon nanotubes Nickel

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To mitigate the accelerating impacts of climate change, extensive research efforts have focused on reducing CO2 emissions and converting CO2 into value-added chemicals. Among the various strategies, the electrocatalytic reduction of CO2 (CO2RR) shows great potential for carbon recycling and renewable energy storage, particularly when coupled with intermittent renewable power sources. In this study, a high-pressure CO2RR system was developed to enhance the local CO2 concentration and suppress the competing hydrogen evolution reaction (HER) in order to enable selective electroreduction of CO2 to CO. The NiO/CNT composite catalyst exhibited superior catalytic performance compared to bare Ni or NiO, achieving a Faradaic efficiency (FECO) exceeding 75.1% at –3.0 V and 6.0 MPa. The synergistic combination of NiO and carbon nanotubes enhanced CO2 adsorption, charge transfer, and intermediate stabilization. This resulted in an improved CO selectivity under elevated pressures. The applied high-pressure conditions further promoted CO2 solubility and interfacial mass transport, while diminishing HER activity. This work provides new mechanistic insights into pressure-dependent CO2 reduction and highlights the critical role of the local microenvironment in determining product selectivity. The findings of this study establish a rational design framework for optimizing CO2RR systems by integrating pressure modulation with conductive composite catalysts in order to develop efficient and durable electrochemical CO2-to-CO conversion technologies.