Structured combustion catalysts based on sintered metal fibre filters

Abstract

Novel efficient structured combustion catalysts based on sintered metal fibre filters (MFF) were developed. To increase specific surface area (SSA), metal fibres were coated by crack-free porous oxide films of SiO 2 , Al 2 O 3 , porous glass, and mesoporous SBA-15 silica. The composite materials presented uniform open macrostructure of the non-treated MFF filters and were suitable supports for deposition of catalytically active phases (Pd, Pt, and Co 3 O 4 ). These catalysts were tested in hydrocarbon (CH 4 , C 3 H 8 ) combustion. Co 3 O 4 supported on MFF without any coating (6.8% Co 3 O 4 /MFF) was the most active for propane total oxidation. At the same time in methane combustion the activity of this catalyst was relatively low. Pd supported on the MFF coated by mesoporous SBA-15 film (0.5% Pd/SBA-15/MFF) demonstrated the highest activity in methane total oxidation due to the high palladium dispersion.The SBA-15 film supported on MFF provided the highest dispersion of the deposited noble metals (Pd, Pt) with an average particle size ∼2.0 nm. The metal nanoparticles formed within the mesopore channels were stable against sintering during calcination and the particle diameter was observed not to exceed the diameter of the silica pores. These catalysts did not undergo deactivation under reaction conditions at temperatures up to 500 • C. On the contrary, the Pd supported on MFF coated by the microporous SiO 2 and Al 2 O 3 films, prepared by sol-gel technique, suffered from metal sintering during the calcination step and also during reaction, demonstrating strong catalyst deactivation.The catalytic filters are suitable materials for assembling different multiple layers to obtain structured catalytic beds with the composition/concentration gradients of active component in the axial direction. The enhanced overall catalytic performance was observed in adiabatic catalytic reactor during propane combustion due to a synergy of the 0.5% Pd/SBA-15/MFF and the 0.5% Pt/SBA-15/MFF catalytic layers assembled in the appropriate order forming gradient catalytic bed.

Structured fiber supports for ionic liquid-phase catalysis used in gas-phase continuous hydrogenation

“…Before IL deposition, the CNF/SMF Inconel were treated in an ultrasonic bath to remove nonanchored carbon (<0.5 wt%). ZSM-5/SMF Fecralloy composite was prepared as described previously [13,14]. SSILP catalysts were prepared by impregnation of the modified SMF disks with a solution containing acetone (8 ml), …”

“…The measurements were carried out in medium-pressure sapphire NMR tubes (pressure <120 bar) and were followed by NMR spectroscopy. 1 H, 13 C, and 31 P NMR spectra were recorded on a Bruker DRX 400 NMR spectrometer. TSPSA and phosphoric acid were used as references for the 1 H, 13 C, and 31 P NMR measurements.…”

“…1 H, 13 C, and 31 P NMR spectra were recorded on a Bruker DRX 400 NMR spectrometer. TSPSA and phosphoric acid were used as references for the 1 H, 13 C, and 31 P NMR measurements. The spectra were fitted with WINNMR, GNMR 4.0, and NMRICMA/MATLAB programs on a PC (nonlinear least squares fit to determine the spectral parameters; the differences between the measured and calculated spectra were minimized).…”

Electrocatalytic and pseudocapacitive properties of cobalt (hydro)oxide films on sintered metal fiber filter

“…Alternatively, sintered metal fiber filter can be less expensive option for the preparation of electrodes. For example, Bekipor ST0AL3-type filter is a mechanically and chemically stable composition of chaotically placed thin metal filaments (d = 2-30 lm), in the form of a panel (thickness 0.51 mm) [21]. Small fiber diameter, density and thickness of this mesh enable to increase the active surface area along with good accessibility of deeper filaments and free-flow of the electrolyte solution.…”

“Sandwich Reactor” for Heterogeneous Catalytic Processes: N2O Decomposition as a Case Study

“…The high surface of SMF allows deposition of a considerable quantity of the catalyst without increasing the thickness of the active phase and a low mass-transfer resistance [13][14][15][16][17].…”