Switching between Formate- and CO-Mediated Reaction Pathways in Methanol Steam Reforming over Size-Dependent Pt−TiO2 Catalysts

Abstract

Methanol steam reforming over Pt-based catalysts is a promising route for on-board hydrogen production, yet its deployment is severely limited by undesired CO formation from conventional *CO-mediated pathways. Herein, we systematically elucidate the structure−selectivity−mechanism relationship of mPt−TiO2 catalysts (m = 0.5–4.5 wt %) by varying Pt loading to tailor Pt nuclearity and Pt−TiO2 interfacial configurations. Structural characterizations reveal a nonmonotonic Pt evolution with increasing loading: isolated single atoms/subnanometer clusters (0.5Pt−TiO2), three-dimensional metallic nanoclusters with weakened metal−support interactions (1.6Pt−TiO2 and 3Pt−TiO2), and an unconventional extended Pt−O−Ti interfacial architecture at high loading (4.5Pt−TiO2), enabled by favorable lattice matching with rutile TiO2.