Nanoscale hybrids for hydrogen production through water splitting using sunlight

A consortium of European universities, research centres and companies, led by IMDEA Materials Institute, is working on the production of new, more efficient hybrids composed of nanocarbons (e.g. graphene) and inorganics (metal oxides) that can produce hydrogen by water splitting using sunlight. These hybrids have recently shown up to 25 more photocatalytic activity than traditional materials.

The research project CARINHYPH, funded by the EU 7th Framework programme, gathers a group of European researchers and industrialists to produce new hybrid nanomaterials for more efficient hydrogen production through photocatalytic water splitting. Hydrogen fuel is one of most promising sources of energy for the future; in addition to having a high energy content, it produces only water after combustion, instead of CO2. Yet one of the challenges is to produce hydrogen efficiently, that is, obtaining a significant amount relative to the energy used to produce it. One of the most promising methods is photocatalytic water splitting, in which a catalyst absorbs sunlight and carries out the splitting of water molecules, somewhat similar to photosynthesis in plants.




Figures: Schematic of nanocarbon/inorganic hybrids for photocatalytic water splitting.


The aim of this project is to produce materials with superior photocatalytic efficiency by combining nanocarbons (Carbon NanoTubes (CNTs) and graphene) with photoactive nanoinorganics such as metal oxides. The potential of these new nano hybrids lies in three aspects:

  • Due to their nanometric size, they have an exceptionally high surface to volume ratio, accessible for the dissociation of water to produce hydrogen.
  • The nanocarbons extend the light absorption range of the hybrid, therefore increasing the amount of solar energy captured for the photocatalytic reaction.
  • The lifetime of the charge generated in the hybrid after light absorption is extended by separating the negative (electron transfer to the nanocarbon) from the positive (the holes stay in the inorganic), thus avoiding their recombination and enabling the completion of the photocatalytic water splitting.

In order to materialise these three features into a more efficient hybrid that can also be produced on an industrial scale and have a positive impact on society, the consortium of this research project comprises partners with different areas of expertise. The nanocarbons will be synthesised by Thomas Swan LTD, a global supplier of high-quality CNTs and graphene. These nanocarbons will be chemically functionalised in Prof. Maurizio Prato´s laboratory at INSTM in order to integrate them with the inorganic to form a hybrid. The integration will take place at IMDEA Materials as well as the Universities of Cambridge and Münster, using techniques such as atomic layer deposition (ALD) and gyroid infiltration. A whole range of novel femto-second spectroscopy techniques will then be used at the University of Erlangen to study the charge transfer process at the nanocarbon/inorganic interface. Photocatalytic efficiency measurements will be performed at Münster, the results of which will be the basis for the construction of a reactor. The reactor will be built by INAEL (an SME from the Madrid region), and it will demonstrate the potential of these materials on a semi-industrial scale.

Towards the final stages of the project the partners will prepare a roadmap for industrial deployment to exploit the new materials developed during the project. This roadmap will include a full life cycle assessment of materials and processes prepared by EMPA.   

The three-year project started in January 2013, and is coordinated by IMDEA Materials Institute (Spain). The total budget for the project is 3.8 MEuros, 75% of which comes from the European Commission. More information can be found on the project website