Decarbonisation Technology February 2026 Issue

hydrogen and captured CO₂, offering a promising alternative for the decarbonisation of the transportation sector. In general, there are four steps for the production of e-fuels (see Figure 1 ); • H₂ production. • Nitrogen (N₂) or CO₂ capture. • Synthesis of new molecules from feed gas. • Final refinement of the raw product. Water electrolysis and CO₂ capture constitute the core upstream steps of e-fuel production. Renewable H₂ is generated via alkaline, proton exchange membrane (PEM), or solid oxide electrolysis (SOE) electrolysers, while CO₂ is sourced from direct air capture (DAC) or, more economically, from industrial emissions. Using these inputs, e-fuels are synthesised through methanol, Fischer-Tropsch (FT), or Haber-Bosch (HB) pathways (Boretti, 2024) . Drop-in fuels such as e-kerosene, e-diesel, and e-gasoline arise from reverse water gas shift and Fischer- Tropsch (RWGS-FT) systems or methanol- based routes. E-methanol serves as a synthetic fuel and chemical intermediate, whereas higher alcohols provide safer handling and better gasoline compatibility ( Panzone, et al., 2020 ) E-ammonia, produced from nitrogen and renewable hydrogen, is increasingly viewed as a leading maritime fuel. E-fuels benefit from existing infrastructure compatibility, combustion system suitability, and growing technological readiness. However, production costs remain high, constrained by electrolyser efficiency and CO₂ feedstock prices. Advances in catalysts, electrolysis, and capture technologies remain essential for large-scale deployment. Methanol-based routes The direct hydrogenation of CO₂ to methanol has become one of the most actively studied routes for carbon utilisation, though the reaction mechanism remains complex and not yet fully elucidated. Achieving high conversion and selectivity under moderate conditions requires highly efficient catalysts capable of activating both CO₂ and H₂. CO₂-to-methanol (direct hydrogenation) Typical CO₂-to-methanol synthesis operates at 220-300°C and 5-10 MPa, achieving methanol

Methanol

Renewable power or byproduct hydrogen

Plant

Figure 2 CO₂-to-methanol circular value chain

selectivity above 70% under optimised conditions. Copper (Cu)-based catalysts remain the benchmark due to their high low-temperature activity, cost-effectiveness, and stable interactions with oxygenated intermediates, minimising poisoning. However, deactivation due to impurities and structural instability remains a problem for these catalysts. To address these issues, multi-component Cu-based catalysts incorporating oxides such as Al₂O₃, ZrO₂, CeO₂, and MgO have been developed (Ren, et al., 2022) . Zirconium dioxide (ZrO₂) stabilises formate and methoxy intermediates, cerium dioxide(CeO₂) introduces oxygen vacancies to promote CO₂ activation (Chang, et al., 2023), and MgO adds basic sites that enhance CO₂ adsorption, nearly doubling methanol yield compared with unmodified Cu-ZnO-ZrO₂ systems (Sajnani, et al., 2025) . CO₂ hydrogenation to methanol thus represents not only an efficient carbon-reuse pathway but also a route toward sustainable energy carriers, chemical feedstocks, and value-added products supporting decarbonisation and circular economy objectives (see Figure 2 ). However, the commercial deployment of CO₂-derived methanol is limited by the cost of renewable hydrogen and CO₂ capture. Continuous progress in catalyst design, reactor integration, and process optimisation is essential to realise the role of methanol in a low-carbon circular economy. Methanol-to-gasoline (MTG) The MTG process converts methanol to gasoline-range hydrocarbons via methanol dehydration to dimethyl ether (DME),