Metal Support Interaction in Pt Nanoparticles Partially Confined in the Mesopores of Microsized Mesoporous CeO₂ for Highly Efficient Purification of Volatile Organic Compounds

Abstract

The Pt/CeO 2 nanocomposites of Pt nanoparticles partially confined in the mesopores of microsized mesoporous CeO 2 (1.0% Pt/CeO 2 -MM) or supported on the surface of CeO 2 nanocubes (1.0% Pt/CeO 2 -NC) with the same Pt loading of 1.0 wt % were prepared by the impregnation of microsized mesoporous CeO 2 or CeO 2 nanocubes with Pt(NO 3 ) 2 aqueous solution, followed by the reduction with NaBH 4 aqueous solution. 1.0%Pt/CeO 2 -MM exhibits much higher catalytic activity for benzene oxidation than 1.0%Pt/CeO 2 -NC. Compared to 1.0% Pt/CeO 2 -NC, the reaction temperatures of T 50 and T 90 (corresponding to a benzene conversion = 50% and 90%) for 1.0% Pt/CeO 2 -MM tremendously decreases by ΔT 50 = 149 °C and ΔT 90 = 196 °C, respectively. The turnover frequency (TOF) of 1.0% Pt/CeO 2 -MM at 140 °C increases by 9.0 times as compared to that of 1.0% Pt/CeO 2 -NC. The tremendous enhancement in the catalytic activity is due to a novel metal support interaction in 1.0% Pt/CeO 2 -MM. The novel metal support interaction is theoretically studied by density function theory (DFT) calculation and experimentally studied by CO-TPR, CO-TPD, H 2 pulse titration, and HRTEM. The theoretical and experimental evidence reveal that the partial confinement of Pt nanoparticles in the mesopores of microsized mesoporous CeO 2 leads to a significant enhancement in the activity of the surface lattice oxygen around the interface between Pt nanoparticles and CeO 2 , thus tremendously increasing the catalytic activity.

The Key Role of Nanocasting in Gold‐based Fe2O3 Nanocasted Catalysts for Oxygen Activation at the Metal‐support Interface

“…The importance of accommodating particles into the pores has also been observed with other supported noble metal catalysts. For example, Pt deposited into microscale mesoporous CeO 2 presented higher activity for the oxidation of benzene, than when Pt was deposited onto ceria nanocubes . This enhancement was proposed to be related to the formation of active interface sites between and the support.…”

“…These results suggest that the presence of gold metallic nanoparticles, partially confined in the internal support mesoporosity, notably promoted the reduction of Fe 2 O 3 , despite the presence of both the nanocrystalline bridges and the mixed phase of Si and Fe oxides. In line with this, Mao et al . have recently postulated that the partial confinement of Pt nanoparticles within the mesopores of microscale CeO 2 , leads to a significant enhancement in the activity of the surface lattice oxygen of CeO 2 at the interface between Pt nanoparticles and the CeO 2 support.…”

“…These results suggest that the presence of gold metallic nanoparticles, partially confined in the internal support mesoporosity, notably promoted the reduction of Fe 2 O 3 , despite the presence of both the nanocrystalline bridges and the mixed phase of Si and Fe oxides. In line with this, Mao et al [23] have recently postulated that the partial confinement of Pt nanoparticles within the mesopores of microscale CeO 2 , leads to a significant enhancement in the activity of the surface lattice oxygen of CeO 2 at the interface between Pt nanoparticles and the CeO 2 support. In the present study, we also observe a modification of the lattice oxygen species from the interaction between confined metallic Au nanoparticles and the support and it could be assumed that these lattice oxygen species could be responsible for increasing the catalytic activity for propane total oxidation.…”

“…For example, Pt deposited into microscale mesoporous CeO 2 presented higher activity for the oxidation of benzene, than when Pt was deposited onto ceria nanocubes. [23] This enhancement was proposed to be related to the formation of active interface sites between and the support. Following this line of reasoning, the present work investigates catalysts consisting of gold deposited on mesoporous Fe 2 O 3 prepared by a nanocasting route for the total oxidation of propane, a representative VOC.…”

Sunlight‐Driven Hydrogen Production Using an Annular Flow Photoreactor and g‐C3N4‐Based Catalysts

“…The incorporation of Pt on photocatalytic surfaces of CN was reported to significantly enhance its photoactivity toward hydrogen production. In this regard, the noble metal plays a crucial role inhibiting electron‐hole recombination by trapping photoinduced electrons ,,. Additionally, different concentrations of MnO x have been incorporated with noble metals on graphitic carbon nitride surfaces to improve the photocatalytic performance of unmodified materials ,.…”