Phase junction-confined single-atom TiO2–Pt1–CeO2 for multiplying catalytic oxidation efficiency

Abstract

Single-atom catalysts (SACs) are advocated for theoretical 100% atom efficiency and high reactivity. Further breakthroughs in catalytic efficiency beyond the present SACs will rely on upgrading the intrinsic activity of each active site via sophisticated catalyst design, which is undoubtedly challenging. Herein, we report the use of the phase junction confinement principle to construct a TiO₂–Pt₁–CeO₂ ensemble with unprecedented reactivity. The reduction-durable TiO₂–Pt₁–CeO₂ unit enabled weakened CO affinity and extensive lattice oxygen activation, which subsequently led to facilitated O₂ activation. Additionally, the TiO₂–Pt₁–CeO₂ interface structure initiated a unique cross-phase oxidation mechanism. The balanced adsorption behaviour, enhanced surface lattice oxygen reactivity, and substantially lowered reaction barrier enabled such a catalyst to realize a great increase in CO oxidation efficiency (300 K) with multiplied specific mass reactivity compared to the impregnated analogue and the pilot Pt₁/FeO_x catalyst. This work demonstrates a plausible synthesis philosophy and reaction mechanism for SACs that will create a new frontier in reactivity.