RT Journal Article
T1 Two-step hybrid photo-thermochemical looping process, using metallic clusters on metal oxide carriers, for very efficient green hydrogen production
T2 Proceso híbrido fototermoquímico de dos pasos, utilizando clústeres metálicos sobre soportes de óxido metálico, para la producción muy eficiente de hidrógeno verde
A1 Nguyen, Anh Dung
A1 Buceta Fernández, David
A1 Dieste Places, Martín
A1 López Quintela, Manuel Arturo
A1 Schomäcker, Reinhard
AB In this work, we demonstrate a sustainable method for producing high-purity hydrogen through a two-step water-splitting process that leverages reducible oxides to store and release oxygen independently of hydrogen. Unlike conventional solar thermochemical (STCH) water-splitting techniques, which require extremely high temperatures exceeding 1000 °C, our approach operates at significantly lower temperatures—below ≈600 °C—thanks to a sunlight-driven photocatalyst composed of silver metal clusters (Ag5) supported on ceria and Ce–Zr oxygen storage materials. This lower-temperature operation not only reduces the demand for high-performance materials for the design of the process but also enhances safety, simplifies system design, and improves the long-term stability of both materials and equipment. Overall, this green technology offers an energy-efficient and environmentally responsible pathway for clean hydrogen production. Density-functional-theory calculations show that Ag5 clusters (1) enhance the photo-absorption, especially in the visible range, by increasing the gap states of the CeO2 surface, and decrease the oxygen vacancy formation energy (EVO) in certain positions around the clusters dramatically, and (2) create active sites in the Ag-CeO2 interface possessing lower reaction energy and activation barrier for the hydrogen evolution reaction. Guided by these studies, we demonstrate a cleaner and more energy-efficient hydrogen production process, achieving an average output of ≈55 mL per cycle (≈435 μmol g−1 h−1). This corresponds to an oxygen vacancy parameter δ ≈ 0.26 per cycle—about 51% of the theoretical maximum—significantly surpassing the performance of traditional high-temperature STCH methods. Notably, our process reaches a solar-to-hydrogen (STH) conversion efficiency of ≈9.7%, placing it at the upper end of the typical STCH range (1–10%) while operating at much lower, intermediate temperatures. These results highlight the strong potential of this greener approach to hydrogen production, offering high efficiency due to the utilization of a broader wavelength range of the solar light and a smaller environmental footprint. Additionally, the use of methane in the reduction cycle promotes the formation of oxygen vacancies, while selectively generating carbon monoxide. The two-step concept has the potential to convert biomethane into a higher-value syngas product, with the added benefit of producing extra hydrogen. This allows for the adjustment of the CO/H2 ratio, enabling subsequent Fischer–Tropsch processing for liquid fuel production.
PB The Royal Society of Chemistry
SN 1463-9262
YR 2025
FD 2025-06-26
LK https://hdl.handle.net/10347/43509
UL https://hdl.handle.net/10347/43509
LA eng
NO Nguyen, A. D., Buceta, D., Wu, Q., López-Quintela, M. A., et al. (2025). Two-step hybrid photo-thermochemical looping process, using metallic clusters on metal oxide carriers, for very efficient green hydrogen production. Green Chemistry (27), 8921-8935. https://doi.org/10.1039/d5gc01425e
NO This research was partially supported by the Consellería de Educación (Xunta de Galicia), Grants No. Grupos Ref. Comp. ED431C-2021/16; Spanish Ministerio de Ciencia e Innovación (MICIU) PID2022-142334OB-I0, financed by MICIU/AEI/10.13039/501100011033 and European Union (ERDF/EU); and TED2021-131899B-I00, financed by MICIU/AEI /10.13039/501100011033 and EU Next Generation (EU/PRTR). CJL and QW acknowledge support from the EPSRC Program grant “Quantum Engineering of Energy-Efficient Molecular Materials”. A. Gili acknowledges support by the German Federal Ministry of Education and Research in the framework of the project Catlab (03EW0015A). JTM and MFB thank the Advanced Light Source, which is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under Contract No. DE-AC02-05CH11231, and where the in situ XRD measurements where conducted at beamline 12.2.2 in the framework of the AP proposals (ALS-11921).
DS Minerva
RD 24 abr 2026