Low-Temperature Ammonia Oxidation in a Microchannel Reactor with Wall-Loaded X(X = Pt, Pd, Rh, PtPdRh)/TiO₂ Nanotube Catalysts

Abstract

In this research, wall-loaded X­(X = Pt, Pd, Rh, PtPdRh)/TiO2 nanotube (NT) catalysts were prepared by deposition via photoreduction with anodized TiO2 nanotubes and were assembled in a microchannel reactor to catalyze ammonia oxidation. Results showed that Pt/TiO2-NTs gave NH3 conversion and NO x selectivity as high as 100% at 280 and 380 °C, respectively. Simulations confirmed that the NO-dissociation energy on Pt(111) is the highest, although the adsorption energy of NH3 and O2 on the Pt(111) surface was between those on Rh(111) and Pd(111), resulting in the easiest NO desorption and, consequently, the best catalytic performance of Pt/TiO2-NTs.

Promoting the Performances of TiO2 Submicrosphere-Embedded Ru Nanoparticles in Benzene Selective Hydrogenation by Morphology Manipulation

“…1 To enhance the performance of TiO 2 , tailoring the morphology with desired porosity, crystallinity, and surface area is a versatile and important route. Until now, mesoporous TiO 2 spheres, 2 monoliths, 3 films, 4 scaffolds, 5 and tubes 6 have been fabricated by microfluidic, macromolecular coassembly, sol−gel, solvothermal, and dualtemplate strategies. Of special focus are monodispersed TiO 2 submicrospheres with abundant pores in suitable diameters because of their submicrometer size, high surface area, tunable pore size, improved diffusivity of substrate and product molecules, and increased number of reaction sites, which make them prime candidates as supports or catalysts in photocatalysis, 7 electrocatalysis, 8 and heterogeneous catalysis.…”

Stepwise Reduction and In Situ Loading of Core‐Shelled Pt@Cu Nanocrystals on TiO2–NTs for Highly Active Hydrogen Evolution

“…TEM image can discriminate the subtle shape and texture character with much greater clarity via contrasting the color difference in different part. [20,24] From the inset TEM image (Figure 2A 1 ), it is easy to identify by dint of the light and shade color difference that the TiO 2 -NTs unfolds a typical hollow tubular structure with a mean wall thickness of ≈5 nm. The SAED image of TiO 2 -NTs, with the multilayer concentric diffraction rings, confirms the polycrystalline structure, from which the crystal faces (101), (200), and (211) of anatase TiO 2 can be designated.…”

“…Titanium dioxide (TiO 2 ), with abnormally high chemicophysical stability, satisfactory mechanical strength, and rich morphology, has been known as one kind of promising and competitive catalytic carrier. 1D structured titanium dioxide nanotubes (abbreviated as TiO 2 –NTs) hold unique porous texture, higher specific surface area and larger cation exchange capacity, [ 19 ] facilitating directional and rapid electron conduction and mass transfer, [ 20 ] therefore facilitating the adsorption and dispersion for the active metal components. [ 21 ] The generation of the synergistic effect among the active metal components and carrier could enhance the catalytic performance of the resulted supported catalysts in a large extent.…”

Continuous-Flow Ammoxidation of 2-Methylpyrazine to 2-Cyanopyrazine with High Space-Time Yield in a Microreactor

“…In recent years, microreactors − had been applied for the ammoxidation reaction, , like from propane to acrylonitrile, and showed good performance by its high heat transfer coefficient. However, the reported MP ammoxidation mainly used Φ20–30 mm fixed-bed reactors (FBR), and the reaction temperature was limited within 450 °C because of possible hot spots at higher temperature.…”