H2MemX - Enabling ultrathin Pd based membranes through surface chemistry diagnostics and control

Palladium (Pd) alloy membranes for separation of hydrogen are under commercialization on basis of identified benefits in terms of separation efficiency, hydrogen purity, membrane stability, and cost relative to existing separation technology. This membrane technology is well suited for integration with different hydrogen production process technologies, in particular hydrogen production from natural gas with carbon capture and storage (CCS) - so-called blue hydrogen. The H2MemX starting hypothesis was that industrial application of Pd alloy membranes for hydrogen separation requires taking the understanding of the membrane chemistry and structure under industrially relevant conditions to a new level. The H2MemX consortium represents unique competence and extensive experience in combining education, fundamental science and industrial relevance through Centre and project grants. Department of Chemical Engineering, NTNU, holds long experience in surface science and fundamental membrane investigations. SINTEF Industry has developed a unique membrane fabrication technology, which has been licensed to Hydrogen Mem-Tech AS, aiming at hydrogen production from natural gas with CO2 capture. An industrial advisory committee was established in 2019, with members from Hydrogen Mem-Tech AS and KA Rasmussen AS. The committee has met with the project researchers three times, and one final meeting is planned for December 2022/January 2023. In the H2MemX project, NTNU and SINTEF have utilized complementary knowledge and an extensive theoretical and experimental toolbox for detailed characterization of Pd based membranes. The advancement of so-called in situ methodology for investigating the membrane surface under working conditions was made in collaboration with Lund University and the MAXIV laboratories. The new MAXIV synchrotron facility in Lund, Sweden, represented a unique possibility for the H2MemX team at project start-up, and the principal investigators were between the first test users for photoelectron spectroscopy under gas exposure at the HIPPIE Ambient pressure X-ray photoelectron spectroscopy (APXPS) beamline. The H2MemX research team obtained and executed three experimental beamtime periods of one week each at the HIPPIE beamline. The first and last period (June -19 and Oct/Nov. 2020) concerned experiments in the unique HIPPIE reaction cell with carbon monoxide (CO) oxidation cycles over Pd75%Ag25% (100) and (111) single crystals, looking at the correlation between segregation of Pd/Ag and reactivity. For the second period (Sept -19), a cell was designed and implemented with 10 µm thin film Pd 23%Ag membranes produced by SINTEF. This allowed characterization of the membrane near-surface region (feed side) during hydriding and permeation in the range from room temperature to 380 °C. Among other things, segregation was observed. These results obtained from the experiments at MAX IV have led to 2 peer-reviewed publications, and we have valuable data that will result in 1 additional paper. Moreover, quantum chemistry modeling results on the combined effects of CO and hydrogen adsorption and PdAg alloy segregation were published in 2020, in collaboration with colleagues at UW Madison, USA. In short, it can be stated that both experiments and theory show that hydrogen, CO and oxygen only bind to Pd atoms in the surface, and this means that Pd is drawn to the outermost atomic layer. But the bonds to hydrogen and CO weaken when the temperature increases, which causes Ag atoms to segregate to the surface. And while a pure Pd crystal tends to form a thin surface oxide at high temperature, this Pd-rich oxide is readily reduced with CO present if the alloy contains 25% silver (Ag). These findings affect how the PdAg membrane functionality should be optimized, including the stability over time. H2MemX will educate one PhD candidate and has promote the research careers of a highly skilled postdoctoral fellow and a young research scientist, both female. The postdoctoral fellow started 2021 in a R&D position in Hydrogen Mem-Tech AS. The PhD main experimental activity is on high precision membrane separation investigations. The research was, however, delayed due to the Covid-19 pandemic, which caused delays in workshop assistance and supply of basic laboratory parts. Our home hydrogen permeation lab is now renovated and up and running and a series of measurements investigating the effect of CO, CO2 and H2O on the hydrogen permeation through thin films Pd-Ag membranes has been completed. A draft PhD thesis and 2-4 scientific papers are expected in 2023. 1 Master thesis in chemical engineering has been affiliated with the project. This is somewhat lower than targeted and is partly due to a demanding recruitment situation within chemical engineering. Otherwise, target accomplishment in H2MemX is high, including popular science dissemination. Expertise and collaboration will (in part) be further developed in FME HYDROGENi

For forskningsfeltet: Forskerprosjektet H2MemX har generert ny innsikt i hvordan Pd-legeringer, enkrystaller og polykrystallinske tynnfilmer, responderer på adsorbater, reaksjon på overflata, samt permeasjon av hydrogen. Vi har også introdusert nye metoder innen forskninga på slike materialer; 1)høypresisjons permeasjonsmålinger uten påvirkning fra masseoverføringsfenomener i gassfasen eller porøs bærer, 2) bruk av teoretiske modelleringsverktøy til å studere segregering og aktivering av hydrogen, og 3) bruk av fotoelektronspektroskopi, både operando og pre/post-karakterisering koplet med eksponering i reaksjonscelle. For kompetanseutvikling: H2MemX utdanner 1 PhD, 1 postdoc. og 1 Master med verdifull FOU-kompetanse innen hydrogenteknologi. For næringslivet: H2MemX har gitt bedre forståelse Pd-membranteknologiens muligheter og begrensninger, spesielt hvilke faktorer som på kort og lang sikt kan påvirke membranenes ytelse. For samfunnet for øvrig: Vi bidrar med grunnleggende material og kjemiteknisk kunnskap, relevant og etterspurt for det grønne skiftet, og med spesifikk kunnskap innen hydrogenteknologi.

PPalladium (Pd) based membranes for separation of hydrogen are under commercialization on basis of identified benefits in terms of efficiency, purity, stability, and cost relative to existing separation technology. This membrane technology is well suited for integration with different hydrogen production process technologies, as well as carbon capture and storage (CCS). The H2MemX main hypothesis is that industrial application of Pd alloy membranes for hydrogen separation requires taking the understanding of the membrane chemistry and structure under industrially relevant conditions to a new level. The H2MemX consortium represents unique competence and extensive experience in combining education, fundamental science and industrial relevance through Centre and project grants. Department of Chemical Engineering, NTNU, represents strong experience in surface science and fundamental membrane investigations. SINTEF Industry has developed a unique membrane fabrication technology that is being commercialized in a joint effort with Hydrogen Mem-Tech AS, aiming at hydrogen production from natural gas with CO2 capture. NTNU and SINTEF hold complementary knowledge and an extensive theoretical and experimental toolbox for detailed characterization of membranes. The advancement of so-called in situ methodology for investigating the membrane surface under working conditions will be pursued in a collaboration with Lund University and the MAXIV laboratories. The new MAXIV synchrotron represents unique possibilities for H2MemX, and the principal investigators have been between the first test users. H2MemX will educate one PhD candidate and promote the research careers of a highly skilled postdoctoral fellow and a young research scientist, both female. 4-6 Master candidates in chemical engineering or nanotechnology will be educated within the project. The final project deliveries includes 6-8 scientific publications, dissemination at conferences as well as an innovation plan.