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

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).