Turning Perspective in Photoelectrocatalytic Cells for Solar Fuels

Abstract

The development of new devices for the use and storage of solar energy is a key step to enable a new sustainable energy scenario. The route for direct solar-to-chemical energy transformation, especially to produce liquid fuels, represents a necessary element to realize transition from the actual energy infrastructure. Photoelectrocatalytic (PECa) devices for the production of solar fuels are a key element to enable this sustainable scenario. The development of PECa devices and related materials is of increasing scientific and applied interest. This concept paper introduces the need to turn the viewpoint of research in terms of PECa cell design and related materials with respect to mainstream activities in the field of artificial photosynthesis and leaves. As an example of a new possible direction, the concept of electrolyte-less cell design for PECa cells to produce solar fuels by reduction of CO2 is presented. The fundamental and applied development of new materials and electrodes for these cells should proceed fully integrated with PECa cell design and systematic analysis. A new possible approach to develop semiconductors with improved performances by using visible light is also shortly presented.

CO2 Reduction of Hybrid Cu2O–Cu/Gas Diffusion Layer Electrodes and their Integration in a Cu‐based Photoelectrocatalytic Cell

“…The development of photoelectrocatalytic (PEC) solar cells for the reduction of CO 2 is an area of fast‐growing interest, although often attention is just focused on the electrocatalysts/electrode aspects. However, cell design (which should meet important aspects for practical application, such as a compact design easy to scale‐up, continuous flow operations, easy recovery of the reaction products and low costs of productions) is often determining the choice of the electrode materials and their characteristics . Therefore, it is crucial that the development of the electrodes is made taking into consideration above aspects.…”

Future Challenges in Heterogeneous Catalysis: Understanding Catalysts under Dynamic Reaction Conditions

“…At the sight of depleting fossil fuel reserves and facing increasing environmental problems connected to their continued usage,1, 2, 3, 4 novel strategies to power our society are presently being developed based on renewable energies. As for example planned within the German “Energiewende”,5 renewable energies in combination with chemical energy conversion will play a crucial role in such future energy scenarios 1, 2, 3, 6, 7, 8, 9, 10.…”

Needs and Gaps for Catalysis in Addressing Transitions in Chemistry and Energy from a Sustainability Perspective

“…However,f rom a practical perspective, the key parameter is the productivity in H 2 per unit cost of the cell, [36] because H 2 recovery becomes an additional cost when production is not physically separated from O 2 evolution. In water splitting, the main parameter analyzed is the solar-to-hydrogen (STH) efficiency or related aspects.…”

“…In addition, these systems may be operated without using al iquid electrolyte (instead using gas diffusion electrodes), [36] which avoid the presence of an electrical double layer and the consequent change in the surfacec haracteristics of the electrodes and in the surfacec oncentration of adspecies. Thus, it may be virtually impossible to obtain high selectivities, according to the conventional electron transfer theory.T os olvet his problem,w em ust combine nanostructured electrodes( foran onuniform potential distribution on the electrode) with the use of catalytic elements, which shunt the reaction pathways from the ideal electron transfer process.…”