Flow-through ag hollow fibre gas diffusion electrodes for electrochemical CO2 reduction

Flow-through ag hollow fibre gas diffusion electrodes for electrochemical CO2 reduction

The challenge of global warming associated with anthropogenic carbon dioxide (CO2) emissions has attracted a great deal of attention around the world, driving the pursuit of technologies to protect the environment for future generations. Electrochemical carbon dioxide reduction reaction (CO2RR) offers a promising approach to achieving carbon neutrality and sustainable development, enabling the conversion of CO2 into fuels and high-value products through renewable energy resources. Over the past decade, significant research has focused on the development of efficient electrocatalyst materials, suitable electrolytes, and optimal electrocatalytic operations. To achieve the desired efficiency and selectivity of products, electrodes should combine with high activity and selectivity, affordability, and robust stability. Gas diffusion electrodes (GDE) exhibit significant potential for achieving high performance of CO2RR as they reduce the distance of gas diffusion paths and provide high reactant concentration to electrocatalytic surfaces. Hollow fibre GDEs (HFGDE) have recently gained much attention as a novel electrode configuration, primarily due to their simple fabrication, and tubular geometry, which provides an expanded active surface area. In this thesis, we focused on the development of Ag-based HFGDE with high selectivity and activity for CO2 conversion in aqueous electrolytes under high current densities, aiming for industrial applications. Initially, the nano/microparticles surface of Ag HFGDE was fabricated through in-situ reconstruction, significantly improved the selectivity of CO production. Then, the microenvironment at the electrode/electrolyte interface on HFGDEs during CO2 conversion processes was modulated by introducing cationic surfactant, which effectivity suppressed the competing hydrogen evolution reaction (HER) and promoted the selectivity of CO production. Finally, we integrated surface reconstruction with local reaction microenvironment regulation on Ag HFGDE, achieved their application at industrially relevant current densities in acidic electrolyte. These findings provide a pathway for optimising electrode design and reaction conditions to achieve more efficient and selective CO2 conversion at industrial scales, which has significant implications for sustainable energy production and carbon conversion technologies.

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