Photoelectrochemistry (PEC) lab
Chemical energy storage by means of electrochemical processes
Electrochemical energy storage
Chemical energy storage
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The main objective of the PEC laboratory is to convert CO2 - through photoelectrochemical (PEC) reduction - into value-added chemicals and fuels, such as syngas, hydrocarbons, and oxygenates compounds using energy that is not produced from fossil fuels, as well as the production of hydrogen by photoelectrochemical water-splitting. Moreover, the integration of renewable energy could make this PEC process a potential candidate for an environmentally sustainable use of CO2 that can support storage, both to reduce total costs and the distance between emission sources and storage sites.
The PEC Lab facility has been conceived in different sections:
a photoanode-driven PEC reactor that consists of a photo-anode half-cell (such as WO3-TiO2 nanotubular structures), a cathode half-cell (such as copper-based electrodes with BDD or TiO2 nanotubes substrates) and a protonic membrane (Nafion®);
a solar simulator (LOT Quantum Design), a potentiostat/galvanostat (Autolab PGSTAT204 with FRA32M electrochemical impedance spectroscopy (EIS) module), a micro-gas chromatograph (Agilent 490) for the analysis of the gas phase and a gas chromatograph (Agilent GC7890A) coupled with a mass spectrometer (Agilent 5977A MSD) to analyze the liquid phase.
two EL-Bronkhorst flow meters to set the gas feeding (CO2 and N2).
The simplified process can be summarized as follows: 1) the light crosses the quartz window and reaches the photoanode, where photo-generated electrons and hole pairs are generated and O2 evolves; 2) the protons pass through the protonic membrane, while electrons are collected and reach the cathode through an external wire; 3) the protons react with CO2 in presence of electrons on the electrocatalyst to produce chemicals or fuels, and each other in order to produce hydrogen. The physical separation of the two reactions in a photoanode and electrocathode respectively is necessary to increase the efficiency of the process and limit charge recombination.
The activities involve the synthesis and electrochemical characterization of Cu based photoelectrodes as well as Cu/Zn-based p-n heterojunctions, and WO3 TiO2 nanotubular structures.