António Vilanova

The solar redox flow cell (SRFC) is an emerging technology that uses semiconductors to photocharge redox pairs, storing solar energy in electrochemical fuels and heat. Despite being in its infancy, significant efforts have been made in the development of high‐efficient materials and in understanding the fundamental processes. However, little attention has been given to device architecture and scalability, which may prove equally important in bringing this technology closer to commercialization. This work is the first attempt at upscaling SRFCs, proposing an innovative 25 cm² photoactive‐area device: the SolarFlow25 cell. A computational fluid dynamics model is developed to implement design key features aiming at: maximizing light absorption by the semiconductor, ensuring effective diffusion and convection of redox species, and guaranteeing minimal electronic and ionic transport resistances. After being connected to a redox flow cell (RFC), the combined SRFC/RFC device is used to photocharge–discharge a ferrocyanide/anthraquinone (2,7‐AQDS) chemistry continuously. A nanostructured hematite (α‐Fe₂O₃) photoelectrode combined in series with a dye‐sensitized solar cell (DSSC) produces an unbiased photocurrent of ≈40 mA. The solar‐to‐output‐electricity‐efficiency remains stable at ≈0.44%, fourfold higher than any other reported hematite‐driven SRFC. The guidelines provided here are expected to help design and upscale future SRFC devices, making solar energy accessible in decentralized locations.

Mitigation of ohmic losses and mass transport limitations enables a large area BiVO₄-based water splitting device with a solar-to-hydrogen efficiency of 2.1%.

TiO ₂ films were prepared for facilitating the evolved gas bubbles to slip over the front window of PEC cells resulting in a transparency improvement of up to 10%.