Boosting methanol steam reforming performance via crystal-phase-driven strong metal-support interactions: From encapsulated Pt nanoparticles to deeply embedded PtOx-induced Pt single atoms

Traditional strong metal-support interactions (SMSIs) induced by encapsulated reducible oxide overlayers on metal nanoparticles can suppress sintering but has a strong negative impact on the catalytic activity because of decreased availability of active sites. Herein, we design three SMSIs configurations on Pt-TiO₂ via crystal-phase engineering. These configurations comprised encapsulated Pt nanoparticle (NPs) with TiO_2−x overlayer on anatase, weakly embedded Pt clusters on P25, and deeply embedded PtO_x-induced Pt single-atom (SA) structure on rutile. These configurations exhibited Pt species at multiple scales, ranging from NPs to SAs. Among them, Pt supported rutile TiO₂ sample (Pt-TiO₂(R)-H) achieved extremely low CO selectivity (2.05%, 200 °C) and optimal H₂ production performance due to the enhanced SMSIs from Pt–Ti coordination in the deeply embedded PtO_x region. This Pt–Ti coordination facilitated the electron transfer from Pt to Ti and induced dual-function centers of electron-deficient Pt^δ+–Pt²⁺ pairs (0 < δ < 2, where Pt^δ+ represent Pt SAs) for methanol decomposition and electron-rich Ti³⁺–oxygen vacancies for water dissociation. Such unique configuration altered the MSR reaction pathway and the kinetic rates of each elementary step in these reaction pathways were systematically analyzed. This work proposes an SMSIs configuration induced by a deeply embedded structure, which mitigates the negative impact on catalytic activity from encapsulated overlayers, meanwhile providing a strategy for developing high-loading Pt SAs catalysts.