During the second reporting period, the DESIRED project made substantial scientific, technical, and organisational progress, consolidating its position as a European frontrunner in solar-fuel technologies. The consortium advanced all major project objectives, delivered high-quality scientific outputs, and significantly strengthened the technological foundations required to demonstrate the DESIRED fuel production system at TRL 4.
Major achievements during RP2 include:
- Breakthroughs in Photocatalyst and Electrode Development
The project delivered multiple generations of novel Cu-oxide–based photocathodes with markedly enhanced stability, charge-transfer efficiency, and selectivity. Notably, DESIRED achieved:
• Multilayer Cu2O/Al2O₃/TiO2 architectures with 2.8-fold higher photocurrent and up to 69% methanol Faradaic efficiency in saline electrolytes, demonstrating compatibility with seawater conditions.
• The first demonstration of time-evolving multicarbon (C2–C₄) products from a Cu2O/Zn₅(OH)₈Cl2 heterostructure, supported by mechanistic DFT analysis connecting chloride chemistry to C–C coupling.
• A new family of hybrid inorganic–organic overlayers that suppresses photocorrosion and doubles the IPCE, extending operation to >20 h.
• New-concept materials that showcase unprecedented C–C coupling behaviour and establish new design rules for next-generation photocathodes.
These advances directly address Objective 1 and significantly expand the scientific basis for selective, stable, and energy-efficient CO2 photoreduction.
- Discovery of Bio-Sourced Frustules as Cu2O Facet Inducers
A particularly impactful discovery was the unexpected facet-selective behaviour of diatom-derived frustules, which act not merely as supports but as inorganic facet inducers for Cu2O nanostructures.
This work:
• Clarified the distinct role of mono-layer (PN) and bi-layer (Cw, Nsp) frustule morphologies.
• Demonstrated selective induction of {111} and {110} Cu2O facets, each associated with different CO2RR product pathways.
• Provided mechanistic insight, supported by DFT, linking Cu–Cu spacing to C–C coupling energetics.
These findings open a new research direction in catalyst design and provide DESIRED with a bio-inspired lever for tuning selectivity, reinforcing Europe’s innovation leadership.
- Design, Engineering and Realisation of the Level 2 Integrated Photoreactor
DESIRED completed the full engineering, construction and integration of the Level 2 photoreactor—a milestone system capable of oscillatory flow, dual-compartment PEC operation, and coupling to a customised solar concentrator.
Key achievements include:
• A validated radiation digital twin, enabling optimum reactor–collector co-design.
• A novel hybrid specular–diffuse reflector with >15% improved optical efficiency compared to purely specular CPC-type designs.
• A fully realised two-compartment, 450 mL Level 2 reactor, compatible with multiple electrode configurations and ready for TRL-4 validation in WP4.
This achievement directly advances Objectives 2 and 3 and lays the foundation for demonstrating DESIRED’s integrated fuel production concept under real solar conditions.
- Advances in Sustainability Assessment and Societal Dimensions
Work in WP5 progressed the Integrated Life Cycle Sustainability Assessment (ILCSA) methodology.
These contributions support Objective 4 and ensure that DESIRED technologies evolve within a sustainability-driven and socially acceptable framework.
- Impact, Dissemination and European Leadership
The consortium significantly intensified its dissemination and engagement activitiesholders and industry.
These achievements strengthen Objective 5 and demonstrate DESIRED’s growing influence within the global artificial photosynthesis and CCU communities.
- Overall Contribution to Long-Term Impact
Across RP2, DESIRED delivered strong evidence of technological feasibility, novel scientific concepts, robust sustainability grounding, and increasing visibility—demonstrating clear progress toward the long-term goal of enabling renewable, carbon-neutral solar fuels and contributing to the EU’s transition to a net-zero greenhouse-gases economy by 2050.
