Crystal-Plane Effects on the Catalytic Properties of Au/TiO₂

Abstract

In this work, Au nanoparticles are loaded on TiO 2 nanocrystals with different crystal planes exposed ({100}, {101}, and {001} planes) to investigate the crystal-plane effect on the catalytic properties of Au/TiO 2 catalyst. Kinetic studies of CO oxidation show that the catalytic activities of three asprepared Au/TiO 2 samples follow this order: Au/TiO 2 -{100} > Au/TiO 2 -{101} > Au/TiO 2 -{001}. Furthermore, different mechanisms exist at low temperatures (<320 K) and high temperatures (>320 K). With the help of ex-situ XPS and in situ DRIFTS, the interactions between substrate molecules and different Au/TiO 2 interfaces are investigated. We find that the activation of O 2 and the formation and desorption of carbonates are greatly dependent on the crystal planes of the TiO 2 support. Furthermore, we use CO oxidation as a probe reaction to study the relationships between surface structures and catalytic properties in Au/TiO 2 . The catalytic behaviors of three Au/TiO 2 catalysts are well correlated with the spectroscopic results. On the basis of this work, we believe that tuning the crystal plane of TiO 2 support will be an effective strategy to control the catalytic properties of Au/TiO 2 .

Crystal-plane effects on surface and catalytic properties of Cu2O nanocrystals for NO reduction by CO

“…It has been reached a general consensus that the catalytic properties are crystal-plane-dependent, thus, well-defined metal oxides nanocrystals are the perfect model catalysts to study the relationships between structural factors and catalytic properties [9][10][11][12]. Cu 2 O, as an important semiconductor, has appeared in many reports about controllable synthesis and catalytic applications.…”

CO oxidation on supported platinum group metal (PGM) based nanoalloys

“…Among different strategies [1], the thermochemical processing strategy (Figure 2), has demonstrated effectivity not only in removing the encapsulation, but also in refining the nanostructural parameters. The synthesis protocol of nanoalloy catalysts could be established by a sequence of steps: (1) chemical synthesis of the metal nanocrystal cores capped with ligands; (2) assembly of the encapsulated nanoparticles on supporting materials (e.g., carbon powders, TiO 2 or SiO 2 ) [15,21,25,54]; and (3) thermal treatment of the supported nanoparticles [55][56][57].…”

“…For instance, to counterbalance the poisoning adsorption of CO on the facet {111} for Pt based catalysts, the activation of molecular oxygen must be further enhanced, whereas high oxidation activity is favored by the appropriate adsorption for both reactant molecules on the facet {100}. The {100} facet of titania, however, is shown to be a most active support template of gold catalyst for CO oxidation [15]. For platinum group metals (PGM) alloyed with other transitions metals (e.g., Ni, Cu, Co, etc.…”

Visible light photoactivity of TiO2 loaded with monometallic (Au or Pt) and bimetallic (Au/Pt) nanoparticles

“…Therefore Au and Pt NPs exist in the Au-core and Pt-shell structure [25]. According to literature data, monometallic photocatalysts, such as Au-TiO 2 and Pt-TiO 2 , were extensively described in the field of catalysis [26][27][28][29][30][31][32], and photocatalysis [33][34][35][36][37][38][39]. In the case of Au-Pt bimetallic combination, literature mainly relies on the widely use of traditional heterogeneous catalysts and show an evidence of electronic transfers from Au to Pt as well as surface ensemble effects, which constitute the good performances observed, for instance, in hydrogenation reactions [21,[40][41][42][43].…”