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Anatase TiO 2 nanosheets (TiO 2 -NS) and nanospindles (TiO 2 -NSP) have been successfully prepared with F – and glacial acetic acid as structure-directing agents, respectively. The Fe 2 O 3 /TiO 2 -NS and Fe 2 O 3 /TiO 2 -NSP nanocatalysts were prepared by a wet incipient impregnation method with a monolayer amount of Fe 2 O 3. All the catalysts were employed for the selective catalytic reduction of NO with NH 3 (NH 3 -SCR) in order to understand the morphology-dependent effects. It is interesting that the Fe 2 O 3 /TiO 2 -NS nanocatalyst exhibited better removal efficiency of NO x in the temperature range of 100–450 °C, which was attributed to more oxygen defects and active oxygen, acid sites, as well as adsorbed nitrate species based on Raman spectra, XPS, NH 3 -TPD, NO+O 2 -TPD, and in situ DRIFTS. The density functional theory (DFT) method was used to clarify the NO and NH 3 adsorption abilities over the catalyst models of Fe 2 O 3 /TiO 2 001 and Fe 2 O 3 /TiO 2 101. The results showed that the NH 3 adsorption energy over the TiO 2 001 (−2. 00 eV) was lower than that over TiO 2 101 (−1. 21 eV), and the NO adsorption energy over TiO 2 001 (−1. 62 eV) was also lower than that over TiO 2 101 (−0. 29 eV), which agreed well with the experimental results that Fe 2 O 3 /TiO 2 -NS achieved higher catalytic activity than Fe 2 O 3 /TiO 2 -NSP for NH 3 -SCR of NO. In addition, the rapid electron transfer and regeneration of Fe 3+ on the 001 facet of Fe 2 O 3 /TiO 2 -NS also promoted the NH 3 -SCR reaction efficiency. This work paves a way for understanding the facet–activity relationship of Fe 2 O 3 /TiO 2 nanocatalysts in the NH 3 -SCR reaction.
Liu et al. (Fri,) studied this question.