Group leader: Dr. Mihalis Tsampas
Renewable energy sources are highly desirable in this era of dwindling petroleum reserves and increasing environmental concerns. Solar energy and wind energy can cover a substantial share of global energy needs, but due to the intermittency and diluteness of these sources, storage in energy-dense commodities, is required.
In the group of photoelectrocatalysis for solar fuel production, we combine solid state electrochemistry with (photo)catalysis to improve the efficiency of existing and to develop new routes for energy storage.
Photoelectrochemical PEC cells for solar fuels
A PEC cell is a device that can potentially achieve water splitting, and thus production of hydrogen or converting CO2 to fuel, using sunlight as the only energy input. Most of the PEC cells described so far in the literature are designed to operate in liquid phases. The main disadvantages of these cells is the low solubility of CO2 in liquid media and the difficulty to scale up.
In our group we focus on the optimization of an alternative PEC reactor and electrode design that can overcome these difficulties by gas phase operation. Reactor design is inspired by polymeric electrolyte membrane (PEM) electrolyzers and thus the two PEC electrodes are separated with an ionically conductive polymeric membrane, while photoelectrode design is based on titania nanotube arrays.
These PEM-PEC cells offer a variety of advantages vs the liquid PEC since they allow gas phase operation which ensures ease access of CO2 to the electrode, direct separation of the reaction products and also offers the possibility of capturing water from the ambient air (which implies that virtually no liquid water is needed for operation, making it a water-neutral process).
Solid oxide electrolyte cells for solar fuels - DIFFER-Syngaschem collaboration
Synthesis gas like carbon monoxide and hydrogen is a key intermediate for reactions that produce energy-rich chemicals such as synthetic natural gas (SNG) and liquid fuels (via Fischer-Tropsch synthesis). These chemicals are easy to use and store and are compatible with existing infrastructure. They are in particular important to store excess electricity inherent to intermittent energy sources such as solar and wind power.
In cooperation with Syngaschem we investigate high temperature water and carbon dioxide co-electrolysis to synthesis gas. Current status of co-electrolysis is limited by material stability issues and lack of understanding regarding the degradation mechanisms. We aim to improve performance of the electrode and electrolyte materials by using design criteria for optimal solid electrode/electrolyte combinations based on computational chemistry and advance characterization tools. Finally, we examine the possibility of coupling this technology with plasma activation for investigation electrocatalysis of vibrationally excited species.