Decomposition of methanol-d4 on a thin film of Al2O3/NiAl(100) under near-ambient-pressure conditions

Guan-Jr Liao; Wen-Hao Hsueh; Yu-Hsiang Yen; Yi-Chan Shih; Chia-Hsin Wang; Jeng-Han Wang; Meng-Fan Luo

doi:10.1063/5.0151135

Decomposition of methanol-d4 on a thin film of Al2O3/NiAl(100) under near-ambient-pressure conditions

J Chem Phys. 2023 May 7;158(17):174707. doi: 10.1063/5.0151135.

Authors

Guan-Jr Liao¹, Wen-Hao Hsueh², Yu-Hsiang Yen¹, Yi-Chan Shih¹, Chia-Hsin Wang³, Jeng-Han Wang², Meng-Fan Luo¹

Affiliations

¹ Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan.
² Department of Chemistry, National Taiwan Normal University, No. 88, Sec. 4, Ting-Zhou Road, Taipei, Taiwan.
³ National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan.

PMID: 37129140
DOI: 10.1063/5.0151135

Abstract

We have studied the decomposition of methanol-d4 on thin film Al2O3/NiAl(100) under near-ambient-pressure conditions, with varied surface-probe techniques and calculations based on density-functional theory. Methanol-d4 neither adsorbed nor reacted on Al2O3/NiAl(100) at 400 K under ultrahigh vacuum conditions, whereas they dehydrogenated, largely to methoxy-d3 (CD3O*, * denoting adsorbates) and formaldehyde-d2 (CD2O*), on the surface when the methanol-d4 partial pressure was increased to 10-3 mbar and above. The dehydrogenation was facilitated by hydroxyl (OH* or OD*) from the dissociation of little co-adsorbed water; a small fraction of CD2O* interacted further with OH* (OD*) to form, via intermediate CD2OOH* (CD2OOD*), formic acid (DCOOH* or DCOOD*). A few surface carbonates were also yielded, likely on the defect sites of Al2O3/NiAl(100). The results suggest that alumina not only supports metal clusters but also participates in reactions under realistic catalytic conditions. One may consider accordingly the multiple functions of alumina while designing ideal catalysts.