Periodic Reporting for period 1 - GH2 (GreenH2 production from water and bioalcohols by full solar spectrum in a flow reactor)
Période du rapport: 2022-10-01 au 2023-09-30
There are enormous global efforts from different research communities to minimize our dependency on grey (fossil-based) or blue (fossil-based with carbon capture and storage) H2. Herein water as the only feedstock and solar energy as the only renewable driving force have been widely recognized as available and sustainable sources for green H2 production.
Water splitting for H2 production driven by solar energy is quite attractive while the current efficiency is very moderate due to both the extremely sluggish water oxidation half reaction and limited light harvesting (mostly UV-visible light). In addition, the separation of one product H2 from the other O2 during water splitting is very costly.
The project is designed to address these challenges by
i) utilizing the full solar spectrum (300-2500nm) instead of UV visible light (300-700nm), ii) coupling water splitting with biomass-derivative oxidation to avoid water oxidation, iii) combining solid Z-scheme UV-visible photocatalysis and Infrared-driven thermal catalysis, and
iv) using a flow reactor instead of batch reactors, targeting to produce green H2 from both water and biomass with a high quantum yield of 60%.
Furthermore, the project will co-produce high-value chemicals with a high selectivity of >90%. In addition, the integration of low-cost and efficient catalysts with novel flow reactors will assure a continuous and efficient production of H2 and high-value chemicals. The entire process does not use fossil fuels nor produce CO2, thus this is a zero carbon-emission technology. Finally, the system can be readily scaled up by numbering up the reactor modules. All these are built upon a multidisciplinary and international consortium with the global experts in photocatalysis, thermal catalysis, reactor engineering, product separation, simulation and social science. Therefore, the scientific and technical challenges, as well as the environmental, societal and economic impacts will be fully addressed in the project. The proposed technology will typically benefit the EU economy by an innovative green H2 production process from water and biomass, heavily contributing to a low carbon society. In addition, the international team including members from Asia will facilitate the technology exploitation out of the EU, to further benefit the EU economy.
Water splitting for H2 production driven by solar energy is quite attractive while the current efficiency is very moderate due to both the extremely sluggish water oxidation half reaction and limited light harvesting (mostly UV-visible light). In addition, the separation of one product H2 from the other O2 during water splitting is very costly.
The project is designed to address these challenges by
i) utilizing the full solar spectrum (300-2500nm) instead of UV visible light (300-700nm), ii) coupling water splitting with biomass-derivative oxidation to avoid water oxidation, iii) combining solid Z-scheme UV-visible photocatalysis and Infrared-driven thermal catalysis, and
iv) using a flow reactor instead of batch reactors, targeting to produce green H2 from both water and biomass with a high quantum yield of 60%.
Furthermore, the project will co-produce high-value chemicals with a high selectivity of >90%. In addition, the integration of low-cost and efficient catalysts with novel flow reactors will assure a continuous and efficient production of H2 and high-value chemicals. The entire process does not use fossil fuels nor produce CO2, thus this is a zero carbon-emission technology. Finally, the system can be readily scaled up by numbering up the reactor modules. All these are built upon a multidisciplinary and international consortium with the global experts in photocatalysis, thermal catalysis, reactor engineering, product separation, simulation and social science. Therefore, the scientific and technical challenges, as well as the environmental, societal and economic impacts will be fully addressed in the project. The proposed technology will typically benefit the EU economy by an innovative green H2 production process from water and biomass, heavily contributing to a low carbon society. In addition, the international team including members from Asia will facilitate the technology exploitation out of the EU, to further benefit the EU economy.
During the first year of the project significant advances has been made in the development of the UV-visible light catalyst and Infrared catalyst to harvest the full solar spectrum. For the UV-visible light catalyst a new photocatalyst was developed using agricultural fertilizer. To utilise the full spectrum of the sunlight, an IR light responsive material was also developed to drive the reaction. Oxygen vacancies engineering strategy was used to introduce extra band in the bandgap of traditional semiconductors, decreasing the photon energy needed for excitation. An efficient IR driven catalyst has been developed, after screening a series of semiconductor support bases and co-catalysts.
Thermal driven catalysts have been developed, as a route to thermally-driven co-catalysts that can be incorporated to UV-visible and IR photocatalysts for a combined photo- and thermal reactor using solely the infrared light for heating. Major efforts were put into synthesis and pre-screening of non-noble, 3d-transition metal catalysts that should be suited. Research focused on Cu catalysts supported on high-surface area oxide supports. The effects of support, of Cu particle size and shape, as well as the effect of water on the reactivity of the prepared catalysts in ethanol steam reforming was investigated.
Band structure studies of semiconductor catalysts were carried out and provided an in-depth learning of photocatalytic H2 evolution mechanism under visible-light and infrared irradiation. In order to exploit the full spectrum of natural light from UV, visible, to near IR, fundamental studies on a chemically and structurally modified UV-visible catalyst were performed. A series of spectroscopic, microstructural and surface-chemical characterisation facilities were established/employed to probe the band and microstructures of the selected photocatalytic systems, including UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), Femtosecond transient absorption spectroscopy (fs-TAS), Nanosecond transient absorption spectroscopy (ns-TAS) scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and electronic paramagnetic resonance (EPR), among others. Those were employed to probe the underlining mechanisms of photon absorption and hot electron dynamics, in relation to structural characteristics. DFT simulations were employed to probe the band structures and guide further improvement of the catalysts.
For the development of a lab-based continuous flow system kinetic models were used to evaluate various reactor configurations and then build the most promising reactor.
Membranes systems were developed for the purification of hydrogen from the gas stream and the recovery of co-added value chemicals from the downstream side of the reactor.
Early-stage Life Cycle Assessment (LCA) and techno-economic analysis (TEA) were conducted for various biomass dehydrogenation routes for several bio-alcohol feedstocks to calculate the maximum environmental and economic potential achievable with such a technology. In parallel, a literature analysis was conducted to gather, categorize, and thoroughly analyze the methodologies, models, and input-output variables adopted and suggested in the scientific community concerning the evaluation of the environmental, societal, and economic impacts of technologies and processes aimed at achieving energy transition.
Thermal driven catalysts have been developed, as a route to thermally-driven co-catalysts that can be incorporated to UV-visible and IR photocatalysts for a combined photo- and thermal reactor using solely the infrared light for heating. Major efforts were put into synthesis and pre-screening of non-noble, 3d-transition metal catalysts that should be suited. Research focused on Cu catalysts supported on high-surface area oxide supports. The effects of support, of Cu particle size and shape, as well as the effect of water on the reactivity of the prepared catalysts in ethanol steam reforming was investigated.
Band structure studies of semiconductor catalysts were carried out and provided an in-depth learning of photocatalytic H2 evolution mechanism under visible-light and infrared irradiation. In order to exploit the full spectrum of natural light from UV, visible, to near IR, fundamental studies on a chemically and structurally modified UV-visible catalyst were performed. A series of spectroscopic, microstructural and surface-chemical characterisation facilities were established/employed to probe the band and microstructures of the selected photocatalytic systems, including UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), Femtosecond transient absorption spectroscopy (fs-TAS), Nanosecond transient absorption spectroscopy (ns-TAS) scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and electronic paramagnetic resonance (EPR), among others. Those were employed to probe the underlining mechanisms of photon absorption and hot electron dynamics, in relation to structural characteristics. DFT simulations were employed to probe the band structures and guide further improvement of the catalysts.
For the development of a lab-based continuous flow system kinetic models were used to evaluate various reactor configurations and then build the most promising reactor.
Membranes systems were developed for the purification of hydrogen from the gas stream and the recovery of co-added value chemicals from the downstream side of the reactor.
Early-stage Life Cycle Assessment (LCA) and techno-economic analysis (TEA) were conducted for various biomass dehydrogenation routes for several bio-alcohol feedstocks to calculate the maximum environmental and economic potential achievable with such a technology. In parallel, a literature analysis was conducted to gather, categorize, and thoroughly analyze the methodologies, models, and input-output variables adopted and suggested in the scientific community concerning the evaluation of the environmental, societal, and economic impacts of technologies and processes aimed at achieving energy transition.
For the UV-Visible light catalyst the project team achieved a remarkable early-stage success by adjusting the structure of the photocatalyst and parameters of hydrogen production from ethanol and generated a 70% Quantum Yield in light-driven production of Hydrogen.
For the IR driven catalyst a flow reactor was designed to systematically investigate the ethanol reforming potential under IR irradiation (>700 nm). Under optimised conditions, the catalyst shows a hydrogen production rate of ca. 4.5 mmol h-1 and a high yield rate (ca. 4.4 mmol h-1) of valuable oxidation product acetaldehyde with a high selectivity of ca. 90%.
For the IR driven catalyst a flow reactor was designed to systematically investigate the ethanol reforming potential under IR irradiation (>700 nm). Under optimised conditions, the catalyst shows a hydrogen production rate of ca. 4.5 mmol h-1 and a high yield rate (ca. 4.4 mmol h-1) of valuable oxidation product acetaldehyde with a high selectivity of ca. 90%.