Carbon deposition–resistant Ni3Sn nanoparticles with highly stable catalytic activity for methanol decomposition

Abstract

Ni3Sn intermetallic compound has the potential to serve as a catalyst for methanol decomposition. However, the catalytic stability of Ni3Sn and the resulting mechanism that governs methanol decomposition has not been elucidated thoroughly. Herein, isothermal tests were conducted to probe the methanol decomposition on unsupported Ni3Sn and Ni nanoparticles synthesized by a thermal plasma process. Ni3Sn exhibited higher selectivities for H2 and CO, more stable catalytic activity, and a higher resistance to carbon deposition than Ni. Synchrotron radiation X-ray diffraction and surface analyses revealed the high phase stability of Ni3Sn during methanol decomposition. Density functional theory calculations indicated that methanol decomposition on Ni3Sn surface preferentially proceeded through OH bond cleavage, followed by CH bond cleavage in the produced intermediates. The activation energies of CH3O and CO dissociation were higher on Ni3Sn than that on Ni surface, which was believed to account for the higher selectivity of Ni3Sn toward methanol decomposition.