Photoelectrosynthetic processes in continuous-flow under concentrated sunlight: combining efficiency with selectivity

Introduction

To be the first CO2-neutral continent by 2050, Europe needs to develop and implement disruptive new technologies, based on scientific breakthroughs. In this regard, utilization of CO2 and organic waste as feedstock to generate valuable products will play a key role in turning the chemical industry on a more sustainable, circular path.

Project Overview

In the SunFlower project, we are going to demonstrate that two high-value processes (CO2 or CO reduction and glycerol oxidation will be studied first) can be synergistically coupled to produce chemicals (such as ethylene and lactic acid) and fuels. This will be achieved using novel photoelectrode assemblies (both photocathodes and photoanodes), original photoelectrochemical (PEC) device architectures, and automated processes.

Hypotheses

The SunFlower project is based on the following three hypotheses:

1. Proper engineering of continuous-flow PEC cells operating under concentrated sunlight will allow current densities similar to the electrochemical (EC) methods.
2. One semiconductor alone can supply the necessary energy input for bias-free operation of PEC cells, while generating two high-value products.
3. PEC methods can provide superior selectivity compared to their EC counterparts, even at high current density operation (as the current density and potential can be decoupled).

Validation Approach

To validate our hypotheses, we are going to use for the first time:

• The pairing of two high-value generating redox processes (none of them being H2 or O2 evolution).
• Concentrated sunlight (which has only been used for water-splitting so far).
• Custom-designed and developed PEC cells, elaborating on the photo-gas diffusion electrode concept.
• Machine learning, based on the broad dataset collected by the sensors built in the PEC system, optimizing the performance at a system level.

Conclusion

The proposed combination of these novel approaches will be of groundbreaking nature; therefore, it opens a whole new arena of solar energy conversion.