Task 3.1 (Subtask 3.1.1). The main goal of this subtask is to develop novel metal hydride-based catalysts for ammonia synthesis at mild temperatures and pressures. The starting point is alkali metal hydrides, such as potassium hydride (KH) and sodium hydride (NaH), confined in graphitic carbon materials, as these nanocomposites have shown to be quite active for ammonia synthesis. These catalysts are tested in our ammonia testing setup, which is capable of testing at pressures and temperatures up to 10 bar and 450°C respectively. The reaction product is connected to an acid trap with an ionic conductivity meter to quantify the ammonia production rate via the adsorption and reaction of the formed gaseous ammonia with the acidic solution leading to a change in the ionic conductivity. Using X the effect of synthesis parameters on the degree of intercalation could be observed. The synthesis procedure of the metal hydride nanocomposites has been developed and already improved through changes in the synthesis (intercalation) procedures. Task 3.1 (Subtask 3.1.2). This subtask addresses the development of highly-active ammonia synthesis catalysts based on metal-nitrogen-hydrogen (M-N-H) materials, particularly mixed-anion materials which induce disorder and vacancies into the catalyst formulation in an effort to enhance the kinetics of ammonia synthesis. In this period, the subtask activity has focused on the commissioning of the ammonia test rig, a variable pressure and temperature gas flow panel with ammonia quantification via the absorption of ammonia in a dilute acid trap followed by ionic conductivity measurements. Catalyst synthesis procedures for metal nitride-hydride formulations have been developed, with initial testing of catalyst performance conducted to establish catalyst activity. In situ synchrotron X-ray powder diffraction studies of lithium nitride-hydride and lithium hydride based formulations have revealed insights into the mechanisms of nitrogen activation and ammonia formation Task 3.1 (Subtask 3.1.3). The main goal of this subtask is to design NH3 synthesis catalysts based on transition metal (TM) nanocluster and nanoparticle-based catalysts. Initial synthesis of catalysts by Pechini method included the TM metal doped cerias and perovskites, which have been structurally characterized. Not all the dopants could be successfully doped in the ceria structure neither in the perovskite, so that the excorporation of the catalytic metal was not yet demonstrated. Different synthesis routes are being currently tested. On the other hand, a setup commissioning for the catalyst performance test has been completed and firs measurements are expected for the oncoming weeks. Task 3.2 (Subtask 3.2.1). This subtask deals with the characterization setups are being adjusted in such a way that air-sensitive samples can be handled in protective atmosphere during data collection for characterization under projected pressure conditions and at high temperatures simultaneously. Additionally, a joint beamtime proposal with UoB for operando X-ray total scattering experiments on LiNH was submitted to Deutsches Elektronen-Synchrotron (DESY). The beamtime was allocated for the experiments in June 2023. Task 3.2 (Subtask 3.2.2). This Subtask deals with the in-situ characterization of ammonia synthesis catalysts by neutron techniques and isotopic exchange with gas flow experiments. Neutrons are particularly well-suited for looking at nitrogen and hydrogen with excellent coherent scattering cross-sections for both elements. Neutron beamtime has been applied for in conjunction with UoB. There has also been computational and other analytical methods developed to more straightforwardly elucidate new reaction mechanisms Task 3.3 (Subtask 3.3.1). This Subtask deals with the development of the first batch of POCS printed in several materials (Al, Ni and Cu alloys) and with various structural parameters (density, cell type and strut dimensions) . A small POCS with different geometry and materials for lab scale trials were delivered at CNR for a preliminary activities. Moreover, A POCS geometry was generated in ANSYS. Task 3.3 (Subtask 3.3.2). This Subtask deals with the development of coating methods based on a dip - spinning technique to deposit thin catalytic layers onto AlSi10Mg Periodic Open Cellular Structures (POCs) with cylindrical shape (10 mm diameter and 15 mm length) and different geometry (BCC, kelvin), manufactured (3D printed) and delivered to CNR by ENGIE. An aqueous liquid medium based on water, glycerol, and polyvinyl alcohol (slurry) has been optimized, through rheological studies, to obtain homogeneous and stable catalytic layers.The bare and activated supports were characterized by SEM/EDX. Moreover, porosity and pressure drop measurement were also measured. Adhesion of the deposited layers, evaluated by accelerated stress test in ultrasound bath, pointed out that the presence of anchoring points, the thermal or anodization pre-treatment (or both) of supports or the primer (DISPERAL P2) utilization (both in the slurry and coated on the supports) play a crucial role in achieving high mechanical stability which is characterized by a weight loss between 0.86 wt% (for BCC structures) and 7.3wt% (for Kelvin structures). Task 3.3 (Subtask 3.3.3). This Subtask deals with the preparation of a range of Fe and Ru based catalyst using commercially scalable routes (in powder and granules shape) for catalytic characterization at bench-scale level at different temperatures and pressures, to establish the optimal operation window and allowing to select the most promising formulation for ammonia synthesis. A setup commissioning for the catalyst performance test has been completed and validated with iron catalyst under standard high temperature/high pressure. Moreover, Ru-zirconia catalyst has been identified as promising for ammonia synthesis under conditions milder than typical Haber Bosch. Task 3.4 (Subtask 3.4.1 and 3.4.2). These subtasks deal with the development and characterization of CMSM selective to NH3 to be used in a membrane reactor. New CMSM with high NH3 permeance and selectivity at temperatures (200 - 250 °C) will be developed by taking advantage of both mechanisms of NH3 permeation: molecular sieving where the gases smaller than the pore will pass and adsorption diffusion which is related to the interaction between the pore and the gas. Among the gases involved, NH3 is the smallest (0.26 nm) compared to H2 and N2 (0.29 and 0.365 nm respectively); thus, at AMBHER membranes with high percentage of ultra-micropores (< 0.35nm) and with pores containing functional groups able to interact with NH3 will be prepared.
D8.3 - INTERIM ACTIVITY REPORT (AMBHER - WP3)
2022
Abstract
Task 3.1 (Subtask 3.1.1). The main goal of this subtask is to develop novel metal hydride-based catalysts for ammonia synthesis at mild temperatures and pressures. The starting point is alkali metal hydrides, such as potassium hydride (KH) and sodium hydride (NaH), confined in graphitic carbon materials, as these nanocomposites have shown to be quite active for ammonia synthesis. These catalysts are tested in our ammonia testing setup, which is capable of testing at pressures and temperatures up to 10 bar and 450°C respectively. The reaction product is connected to an acid trap with an ionic conductivity meter to quantify the ammonia production rate via the adsorption and reaction of the formed gaseous ammonia with the acidic solution leading to a change in the ionic conductivity. Using X the effect of synthesis parameters on the degree of intercalation could be observed. The synthesis procedure of the metal hydride nanocomposites has been developed and already improved through changes in the synthesis (intercalation) procedures. Task 3.1 (Subtask 3.1.2). This subtask addresses the development of highly-active ammonia synthesis catalysts based on metal-nitrogen-hydrogen (M-N-H) materials, particularly mixed-anion materials which induce disorder and vacancies into the catalyst formulation in an effort to enhance the kinetics of ammonia synthesis. In this period, the subtask activity has focused on the commissioning of the ammonia test rig, a variable pressure and temperature gas flow panel with ammonia quantification via the absorption of ammonia in a dilute acid trap followed by ionic conductivity measurements. Catalyst synthesis procedures for metal nitride-hydride formulations have been developed, with initial testing of catalyst performance conducted to establish catalyst activity. In situ synchrotron X-ray powder diffraction studies of lithium nitride-hydride and lithium hydride based formulations have revealed insights into the mechanisms of nitrogen activation and ammonia formation Task 3.1 (Subtask 3.1.3). The main goal of this subtask is to design NH3 synthesis catalysts based on transition metal (TM) nanocluster and nanoparticle-based catalysts. Initial synthesis of catalysts by Pechini method included the TM metal doped cerias and perovskites, which have been structurally characterized. Not all the dopants could be successfully doped in the ceria structure neither in the perovskite, so that the excorporation of the catalytic metal was not yet demonstrated. Different synthesis routes are being currently tested. On the other hand, a setup commissioning for the catalyst performance test has been completed and firs measurements are expected for the oncoming weeks. Task 3.2 (Subtask 3.2.1). This subtask deals with the characterization setups are being adjusted in such a way that air-sensitive samples can be handled in protective atmosphere during data collection for characterization under projected pressure conditions and at high temperatures simultaneously. Additionally, a joint beamtime proposal with UoB for operando X-ray total scattering experiments on LiNH was submitted to Deutsches Elektronen-Synchrotron (DESY). The beamtime was allocated for the experiments in June 2023. Task 3.2 (Subtask 3.2.2). This Subtask deals with the in-situ characterization of ammonia synthesis catalysts by neutron techniques and isotopic exchange with gas flow experiments. Neutrons are particularly well-suited for looking at nitrogen and hydrogen with excellent coherent scattering cross-sections for both elements. Neutron beamtime has been applied for in conjunction with UoB. There has also been computational and other analytical methods developed to more straightforwardly elucidate new reaction mechanisms Task 3.3 (Subtask 3.3.1). This Subtask deals with the development of the first batch of POCS printed in several materials (Al, Ni and Cu alloys) and with various structural parameters (density, cell type and strut dimensions) . A small POCS with different geometry and materials for lab scale trials were delivered at CNR for a preliminary activities. Moreover, A POCS geometry was generated in ANSYS. Task 3.3 (Subtask 3.3.2). This Subtask deals with the development of coating methods based on a dip - spinning technique to deposit thin catalytic layers onto AlSi10Mg Periodic Open Cellular Structures (POCs) with cylindrical shape (10 mm diameter and 15 mm length) and different geometry (BCC, kelvin), manufactured (3D printed) and delivered to CNR by ENGIE. An aqueous liquid medium based on water, glycerol, and polyvinyl alcohol (slurry) has been optimized, through rheological studies, to obtain homogeneous and stable catalytic layers.The bare and activated supports were characterized by SEM/EDX. Moreover, porosity and pressure drop measurement were also measured. Adhesion of the deposited layers, evaluated by accelerated stress test in ultrasound bath, pointed out that the presence of anchoring points, the thermal or anodization pre-treatment (or both) of supports or the primer (DISPERAL P2) utilization (both in the slurry and coated on the supports) play a crucial role in achieving high mechanical stability which is characterized by a weight loss between 0.86 wt% (for BCC structures) and 7.3wt% (for Kelvin structures). Task 3.3 (Subtask 3.3.3). This Subtask deals with the preparation of a range of Fe and Ru based catalyst using commercially scalable routes (in powder and granules shape) for catalytic characterization at bench-scale level at different temperatures and pressures, to establish the optimal operation window and allowing to select the most promising formulation for ammonia synthesis. A setup commissioning for the catalyst performance test has been completed and validated with iron catalyst under standard high temperature/high pressure. Moreover, Ru-zirconia catalyst has been identified as promising for ammonia synthesis under conditions milder than typical Haber Bosch. Task 3.4 (Subtask 3.4.1 and 3.4.2). These subtasks deal with the development and characterization of CMSM selective to NH3 to be used in a membrane reactor. New CMSM with high NH3 permeance and selectivity at temperatures (200 - 250 °C) will be developed by taking advantage of both mechanisms of NH3 permeation: molecular sieving where the gases smaller than the pore will pass and adsorption diffusion which is related to the interaction between the pore and the gas. Among the gases involved, NH3 is the smallest (0.26 nm) compared to H2 and N2 (0.29 and 0.365 nm respectively); thus, at AMBHER membranes with high percentage of ultra-micropores (< 0.35nm) and with pores containing functional groups able to interact with NH3 will be prepared.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
