New solution for green hydrogen production

Scientists at Paderborn University are researching carbon materials for photocatalysis

Universität Paderborn

Coal, gas, oil: the use of fossil fuels is declining. Clean energy gained from renewable sources is gradually supplanting its polluting competition. For an energy source to be able to be widely used, it must be affordable and, above all, available. In recent years, hydrogen has proven to be particularly suitable for various applications. However, its production currently usually requires fossil fuels. To change this, scientists at Paderborn University are working on a new research project to examine how hydrogen could be obtained from solar energy using specific carbon materials – in other words, thoroughly green. This project, entitled ‘C2-SPORT’ (standing for ‘Carbon Composites as Direct Z-Scheme Photocatalysts for Overall Water Splitting’), is receiving around 20,000 euros of funding as part of Paderborn University’s internal Wissenschaftskolleg. 

‘Using sunlight for water splitting in hydrogen and oxygen brings us a step closer to the ideal concept of a profitable, environmentally friendly energy source’, explains Junior Professor Maria Nieves López Salas of the Department of Chemistry at Paderborn University, who is heading up the project with Dr. Ying Pan, also from the Department of Chemistry. Their concept is based on what is known as the ‘direct Z-scheme’, a method inspired by natural photosynthesis. In simple terms, this involves combining two types of semiconductors. What makes this process special is that it incorporates the strengths of both types, achieving a previously unheard-of level of efficiency in water splitting. López Salas explains: ‘Semiconductor-based photocatalytic water splitting using solar energy to produce hydrogen and oxygen from water has proven to be a promising solution for tackling energy and environmental issues’. However, there are still obstacles to overcome: for example, splitting water entirely into hydrogen and oxygen using just one catalyst material is extremely difficult. ‘In photocatalytic reactions, light absorption, charge carrier separation and the surface reactions of catalysts work together to create hydrogen from sunlight. To ensure high efficiency, these catalysts must be able to absorb light and separate charges efficiently, among other things’, López Salas adds. The currently available semiconductors that consist of a single material struggle to meet these requirements.

Semiconductors containing carbon could be an interesting option for Z-scheme photocatalyst systems. This is partly because they offer good photocatalytic activity and are lighter than other materials such as titanium dioxide. They are also cheaper, reliable, and widely available on this planet. Suitable strategies that need to be researched could make them excellent candidates for hydrogen production. Pan notes: ‘Understanding this will have a significant impact on the search for technologies to convert solar energy into hydrogen energy. It could form the basis for extremely efficient catalysts and represent a major step towards new artificial photosynthesis devices.’

This project has been funded under the Paderborner Wissenschaftskolleg since April of this year. The aim is to create new research impetus at Paderborn University via interdisciplinary research projects and international collaborations. The call for tender is open to applicants from all fields and is aimed at postdoctoral researchers. The Wissenschaftskolleg offers an opportunity to work together with colleagues from foreign universities or research institutions on internationally oriented research projects. Visiting researchers from universities in Australia and China are also involved in the ‘C2-Sport’ project.