Development of processes for direct production of hydrogen from sunlight

Aim of the project is the development of full technology (i.e. materials selection, prototype development, techno-economical evaluation) for direct water splitting from sunlight, followed by a demonstration of up scaling and the set-up of a prototype production equipment. A photo-electrochemical approach, employing either single-photo-electrode cells or tandem cells should be followed for this purpose. A pure photocatalytic approach cannot be excluded a-priori, but it should be clearly demonstrated to be applicable for the developed system.

Goals should be obtained considering a wide variety of solids, with particular attention to cheap and chemically robust systems (e.g. metal oxides, nitrides, Si-based materials). A preliminary screening using both theoretical (band gap and band energies calculations) and experimental tools (photosensitivity, charge separation capability) is required in order to identify suitable system to be tested in a true photocatalytic apparatus.

Proposals should also aim at the development of an innovative device that is able to overcome the limitations occurring in current state-of-the-art technologies. The new cell concept should be development based on optimized photo-catalysts to be suited for large-scale production processes, as demonstrated by a prototype system.

The proposals should put their main emphasis on following topics:

• selection of materials with optimised photocatalytic properties
• proof-of-concept for a new photo-electrolysis device concept for decentralised hydrogen production
• demonstration of solar-to-hydrogen reliable and efficient conversion at demonstrator scale
• investment cost for the new technology estimated by a socio-techno-economical assessment

Projects are expected to start at TRL 3 and to reach at least TRL 5.

Proposals should build upon experience and results from previously funded projects both on national and European level on component and system development.

The FCH 2 JU considers that proposals requesting a contribution from the EU of EUR 2.5 million would allow the specific challenges to be addressed appropriately. Nonetheless, this does not preclude submission and selection of proposals requesting other amounts.

Expected duration: 4 years

A maximum of 1 project will be funded under this topic.

The direct conversion of solar energy to hydrogen remains a fundamental goal for the forthcoming energy economy based on renewable sources. It is therefore important to develop new and less expensive technologies for obtaining hydrogen by water photo splitting using sunlight. These aims are fully based on the recommendations from the ongoing Green Hydrogen Study.

To bring photo-electrolysis to a commercially viable level, main efforts have so far been focused on the development of new photo-catalytic materials with high efficiencies at lower costs. Systems with relatively high efficiency are usually composed by expensive and often chemically unstable materials, while other less sophisticated systems do not yet have satisfactory yields. While benchmark materials have been established over the past few years, none of the materials is close to being optimised yet. In fact, a basic problem remains to be solved which is the development of both novel semiconductors with superior electronic properties and optimal potentials, additionally showing a high capability of absorbing the visible components of sunlight.

In order to further advance the technology towards the market, the materials research must be accompanied by development of reliable and highly flexible photo-electrolysis devices that operate at high solar-to-hydrogen-efficiencies and exhibit lower production costs. Advanced device engineering is required to maximise electrode performance, optimise the mass and current transfer characteristics, and prevent corrosion and photo-corrosion. An operative prototype with significant hydrogen production, able to consider the effect of variable solar illumination, has not been developed yet.

A real proof of concept and not a simple benchmarking is mandatory as a result of the project.

Expected outcomes from the project are the following:

• Full analysis (e.g. definition of materials, project of the system, BoP, effect of a variable solar irradiation, thermal management) of photocatalytic systems for direct hydrogen production from sunlight
• A prototype system with an exposed surface higher than 10 m² has to be developed with selected material, including full gas control (i.e. hydrogen and oxygen collection, purification, online analysis, storage, etc.) Optimized management of the prototype should be demonstrated
• Specific targets to be obtained by the prototype system are the following:
  • H₂ production demonstrated > 15 g/h or 10 Kg_H2 over the complete running time
  • Efficiency > 5 %
  • Running time > 6 months with a degradation lower than 10% under harsh operating conditions
  • H₂ cost < 5 €/kg H₂
• The materials selected and most promising should be upscaled and proved through in-field testing
• A cost analysis of the developed technology must be performed