Interaction between noble metals (Pt, Pd, Rh, Ir, Ag) and defect-enriched TiO2 and its application in toluene and propene catalytic oxidation

The particle size, electronic state, as well as metal-support interaction of supported noble metal catalysts significantly influence their VOC oxidation performance. A series of noble metals (including Pt, Pd, Rh, Ir, and Ag) was successfully loaded on TiO2 modified by hydrogen reduction to scrutinize their effects on toluene and propene combustion. The prepared catalysts were characterized by SEM, TEM, BET, XRD, ESR, UV–vis, H2-TPR, XPS, in-situ DRIFTS, GC–MS and DFT calculations. It was interesting to note that all the noble metals could be well-dispersed on the low-surface-area TiO2 support and modulated its properties. The electron transfer ability and oxygen mobility of the as-prepared materials were enhanced via noble metal doping. Among them, the Pd/TiO2 and Pt/TiO2 catalysts exhibited excellent catalytic performance by inducing local electron transfer from TiO2 to the noble metal NPs via the strong metal-support interaction. Experimental results and theoretical calculations revealed that the activation of toluene, propene and oxygen on suitable interfaces contributed to the good performance of the Pd and Pt catalysts. This work explored and elucidated the effects of electron-rich noble metal catalysts in enhancing the activation of ground-state oxygen.