TY  - JOUR
AU  - Engel, Robin
AU  - Romeggio, Filippo
AU  - Ocampo-Restrepo, Vivianne K.
AU  - Schouenborg, Jonathan F.
AU  - Billeter, Emanuel
AU  - Soldemo, Markus
AU  - Degerman, David
AU  - García-Martínez, Fernando
AU  - Kibsgaard, Jakob
AU  - Chorkendorff, Ib
AU  - Nørskov, Jens K.
AU  - Damsgaard, Christian Danvad
AU  - Nilsson, Anders
AU  - Lömker, Patrick
TI  - Mechanistic insights into methanol production on Ni<sub>5</sub>Ga<sub>3</sub> thin films: An in situ XPS and DFT study 
JO  - Applied catalysis / B
VL  - 381
SN  - 0926-3373
CY  - Amsterdam
PB  - Elsevier
M1  - PUBDB-2025-04543
SP  - 125798 
PY  - 2026
AB  - The intermetallic compound δ-Ni5Ga3 has emerged as a promising catalyst for CO2 hydrogenation to methanol, offering high selectivity at low-pressure operation, and enhanced stability compared to conventional Cu/ZnO catalysts. However, the fundamental understanding of its active sites, reaction mechanisms, and deactivation pathways remains incomplete, hindering its further development. In this study, we utilize well-defined δ-Ni5Ga3 thin film model catalysts synthesized via magnetron sputtering to investigate these aspects under realistic reaction conditions. We investigate the evolution of the catalyst with temperature employing in situ ambient pressure X-ray photoelectron spectroscopy (AP-XPS) at 300 mbar, microreactor activity measurements, temperature-programmed desorption (TPD), and density functional theory (DFT) calculations. Our experiments show the active catalyst as mostly metallic with only small amounts on oxidized gallium, which gradually reduces and gives way to an increased nickel-concentration at the surface at higher temperatures, accompanied by carbide-growth. We further observe the temperature-evolution of key intermediates, such as carboxyl, formate, and methoxy species. Based on these observations, we discuss distinct pathways for methanol synthesis and CO2 methanation, with methoxy formation correlating directly with methanol activity, as well as the deactivation mechanism. 
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1016/j.apcatb.2025.125798
UR  - https://bib-pubdb1.desy.de/record/639457
ER  -