To combat global warming, it is essential to reduce CO₂ emissions to zero or even below zero. The PHOENIX project aims to gradually convert CO₂—first into carbon monoxide (CO), then into propanol (a liquid fuel)—while simultaneously converting PET plastic into glycolic acid, a valuable chemical compound. The basis of this innovative concept is a special reaction pathway with several reactors that seamlessly combines the technologies of photovoltaic electrolysis (PV-EC) and photoelectrochemistry (PEC). To this end, PHOENIX is developing a powerful tandem photovoltaic system and novel electrocatalysts for converting CO into propanol and PET into glycolic acid – supplemented by highly efficient photoelectrodes. PHOENIX is deliberately pursuing a high-risk, high-potential approach with the aim of achieving a real breakthrough in the field of renewable energies while contributing to the solution of two global environmental problems.

Normal solar cells are not sufficient for this because they do not generate the necessary voltage. Additional energy is therefore often supplied – PHOENIX wants to avoid this. The goal is to develop a so-called tandem solar cell that is powerful enough on its own to directly power the entire process – without any additional power source.

This tandem cell, developed at ZSW, consists of two light-active layers: a Cu(In,Ga)Se2 layer and a perovskite layer. Both materials can be adjusted so that together they generate a particularly high voltage of over 2 volts, which is sufficient for the reaction. The central issue is the production of the tandem using scalable technologies that could also be used in industrial manufacturing. The lower CIGS layer of the solar cell is produced in a highly scaled continuous coating system. Slot die coating is used for the upper layer of perovskite. This enables larger cell areas, but also presents challenges: The layer thickness must be precisely controlled, the ink must flow evenly, and the film must be of the same quality throughout. The end result should be a tandem solar cell with an active area of several square centimeters that supplies enough current and voltage to drive the desired chemical reaction – an important step toward practical application (technology readiness level 4).

Project Website: https://phoenix-heu.eu/

LinkedIn Channel: https://www.linkedin.com/company/phoenix-heu

Cordis Subpage: https://cordis.europa.eu/project/id/101172764