Nowadays, the energy transition including the circular economy of carbon dioxide constitutes one of the major world challenges. The green hydrogen production and the conversion of CO2 into value-added chemicals and/or fuels, using renewable energy and earth-abundant elements as well as environmental friendly materials is a key priority. In this scenario, besides the highly efficiency water splitting processes, several features such as the CO2 capture, the electro-chemical efficiency of the CO2 conversion processes in sub products and the separation of one of these ones from the electrolyte and the other sub products have paramount importance. So, the energy efficiency based on a better detailed knowledge and understanding of the involved mechanisms concerning to the catalyst as well as the processes taking place at the electrode and cell level constitute the clue for assuring a clear industrial feasibility. This strategy allows us to define what it would take for renewably based electro-synthesis products to substitute those obtained from petrochemical processes.
For it, in this project, new strategies on the catalysts morphology and structure and on the electrodes and reactor design is developed with special attention paid in achieving reduced overpotential values, improved selectivity and increased productivity, aside of the H2, towards determined sub products from the CO2RR or NRR such as syngas, methanol or even double bonded carbon molecules like ethylene or ammonia in the case of nitrogen. All this must lead to achieve a competitive overall chain from solar to fuels merit figure above 12% or higher solar to hydrogen values assuming a solar energy conversion to electricity of 20% as reference. Likewise, efforts will also be promoted to reduce the aspects related to degradation and to develop regeneration methodologies to extend the useful life of these systems for promoting the routes for their scale-up.
Specially, among other, new catalysts based on transition metals considering their morphology and structure, replacing oxides with sulfides, selenides or phosphides will be considered taking into account the requirements of the selective steps from the molecule adsorption up to obtaining the desired product, while increasing the current densities >100 mAcm-2 keeping high faraday efficiencies.
Likewise, the environment of the catalyst and the structure of the gas diffusion electrodes will be considered both to carry out an electrolysis both in the liquid phase and in the gas phase.
These research actions are addressed to corroborate the industrial feasibility and competitiveness of the electro conversion of H2O, CO2 and N2 as alternative for the future energy models considering solar refineries, working with or without direct illumination, as energy paradigms delivering high current densities at low voltage cells improving energy balance and keeping high stability, in order to achieve products substituting those from petrochemical processes.
Este proyecto ha sido financiado a cargo del Programa Estatal de Generación de Conocimiento y Fortalecimiento Científico y Tecnológico del Sistema de I+D+i y de I+D+i Orientada a los Retos de la Sociedad, en el marco del Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020. Financiado por el Ministerio de Ciencia e Innovación (MICINN) a través de la Agencia Estatal de Investigación.