A Closed-Loop System for Carbon-Neutral Fuel Production: Integrating Seawater Electrolysis and Direct Air Capture

Dulwich College Beijing, 100103 Beijing, China

^* Corresponding author: aurelie.labarre26@stu.dulwich.org

Abstract

This study explores a closed-loop system that integrates seawater electrolysis with direct air capture (DAC) for the sustainable production of carbon-neutral fuels. By harnessing renewable energy, hydrogen is generated from seawater, while carbon dioxide is extracted directly from the atmosphere. These feedstocks are subsequently utilized in catalytic processes, such as methanol synthesis, the Sabatier reaction, and Fischer– Tropsch synthesis, to produce a range of valuable hydrocarbon fuels. This integrated approach presents a promising strategy to decarbonize hard-to- abate sectors, particularly transportation and heavy industry, which are major contributors to global greenhouse gas emissions. This paper evaluates the technical feasibility of key system components, including the electrolyzer and DAC unit, and examines the impact of catalyst selection, reaction conditions, and system integration on overall efficiency and fuel yield. Special attention is given to the challenges of catalyst degradation in saline environments, energy input optimization, and scalability. Economic and environmental assessments are provided to determine the viability of implementing such systems at scale. Overall, this study offers a comprehensive analysis of the potential role of seawater electrolysis–DAC integration in supporting global decarbonization targets and facilitating a transition to circular, carbon-neutral fuel cycles.