Phase-dependent of ZrO2 supported palladium catalysts for high-efficiency ethane combustion

Supported palladium catalysts have shown remarkable activity in the catalytic combustion of anthropogenic short-chain alkanes; however, the influence of the support crystal phase on catalytic behavior remains insufficiently elucidated. Herein, we systematically unveil the polymorphic effect of ZrO2 support (monoclinic ZrO2: m-ZrO2; tetragonal ZrO2: t-ZrO2; and hybrid phase of monoclinic and tetragonal ZrO2: h-ZrO2) on the catalytic performance of Pd species for ethane combustion. Among these materials, Pd/m-ZrO2 delivers an exceptional specific reaction rate of 6.49 nmolꞏm-2ꞏs-1 at 260 °C, representing 1.5- and 11-fold enhancement over Pd/h-ZrO2 and Pd/t-ZrO2 counterparts. Mechanistic investigations reveal that this superiority stems from a tripartite synergy governed by support polymorphism: (i) robust metal‒support interactions (MSIs) not only epitaxially stabilize highly dispersed PdOx clusters but also downshift the Pd d-band center to an optimal energy level; (ii) Phase-induced charge transfer at the Pd/m-ZrO2 interface lowers the oxygen vacancy formation energy, thereby accelerating the Mars-van Krevelen (MvK) redox cycle via enhanced lattice oxygen mobility; (iii) Abundant Lewis acid sites on Pd/m-ZrO2 facilitates the polarization and cleavage of C–H bonds (the rate-determining step). Furthermore, the robust Pd–Zr interfacial bonding endows Pd/m-ZrO2 with exceptional water resistance by mitigating hydroxyl poisoning. This work provides molecular-level insights into how support polymorphism orchestrates EMSIs and surface reactivity, establishing a design paradigm for efficient alkane abatement catalysts.