The mechanism of room temperature catalytic C-H dissociation and oxygenation of formaldehyde over nano-zirconia phase-junction

The room temperature catalytic efficiency of formaldehyde (HCHO) is determined by interfacial electrons transfer properties, gas adsorption configuration and reactivity of catalysts. The phase-junctions with lattice planes of high matching degree and abundant active sites may do better in the above three aspects than traditional catalysts and their heterojunctions. In this work, tetragonal-monoclinic nano-zirconia (ZrO2 ) phase-junctions (TMZ) were synthesized for the first time. The highest conversion efficiency of HCHO into CO2 was around 81% at 25 degrees C exceeded the value for pure ZrO2. Density functional theory calculations and in-situ diffuse reflectance infrared Fourier transform spectroscopy measurements revealed that the adsorption enhancement of rich zirconium sites and single electron activation at TMZ interface caused C-H dissociation of HCHO and hydrogenation of O-2 (D-H), significantly lowering the activation barrier of catalytic oxidation of HCHO. Our findings can facilitate further design of more active catalyst for room temperature removal of HCHO.