Lattice Hydroxyl-Assisted Platinum Single Atom Catalyst Toward Hydrogen Production From Methanol Aqueous Reforming

Methanol aqueous reforming reaction (APRM) provides a green and clean route towards hydrogen production, in which the structure design and preparation of efficient catalysts remains a challenge. Herein, we report a platinum catalyst supported on the porous hydroxyl lanthanum oxide, which is prepared via glycine combustion method followed by a reduction process. The optimized 0.8%Pt/La catalyst, which is featured by Pt single-atom dispersed on a La₂(OH)_{2 x}O_{3-2 x} support, exhibits an extraordinary catalytic performance towards APRM. A H₂ production rate of 7672 µmol_H2 g_cat ^-1 min^-1 and an average turnover frequency (ATOF) of 11973 h^‒1 are obtained, which is preponderant to the state-of-the-art catalysts. An in-depth investigation based on kinetic isotope analysis, in situ spectroscopy characterizations and theoretical calculations substantiates that Pt single atom coordinated with adjacent lattice hydroxyl (OH_L) with electron transfer from Pt to support serves as the intrinsic active site, in which the Pt^{δ +} site promotes the dehydrogenation of methoxyl whilst lattice hydroxyl directly participates in the oxidative coupling process (CH₂O* + OH_L → CH₂OOH*). Furthermore, the Pt^{δ +}-(OH_L)_x-La interface sites can remarkably reduce the energy barrier of CH₂OOH* dehydrogenation (rate-determining step), and the resulting hydroxyl vacancies can boost H₂O dissociation to recover consumed OH_L, accounting for the exceptional catalytic performance.