Liquid-Feed Flame Spray Pyrolysis of Nanopowders in the Alumina−Titania System

Abstract

We report here the synthesis of (TiO 2 ) x (Al 2 O 3 ) 1-x nanopowders with molar ratios that span the TiO 2 -Al 2 O 3 composition range. The nanopowders were synthesized using liquid-feed flame spray pyrolysis (LF-FSP) of mixtures of N(CH 2 CH 2 O) 3 TiOiPr (titanatrane isopropoxide) and N(CH 2 CH 2 O) 3 Al (alumatrane) dissolved in the appropriate molar ratios in alcohols used as solvent and fuel. Ethanol, methanol, and butanol were used in an attempt to regulate the flame temperatures, particle sizes, and size distributions, as well as to influence the phase(s) produced in selected mixed-phase materials produced at x ) 0.5. The as-produced powders were characterized in terms of phase, size, specific surface area, composition, and morphology by BET, XRD, SEM, TEM, and TGA-DTA. At compositions close to Al 2 O 3 , the δ phase is the primary phase observed. As the compositions approach x ) 0.5, a combination of rutile, R-Al 2 O 3 , and Al 2 TiO 5 is observed. Pure titania powders consist of 90:10 mixtures of anatase and rutile; however, doping with x ) 0.05 of alumina results in 40:60 anatase/rutile mixtures and nearly pure rutile phase at x ) 0.15. The source of this latter phase transformation can be explained in terms of Al 3+ substituting for Ti 4+ ions in the anatase lattice forcing the phase transformation as found in highly defective TiO 2 . No effect of flame temperature as a function of fuel was observed.

Flame-spray pyrolysis preparation of perovskites for methane catalytic combustion

“…Formerly, the main limitation was due to the availability of volatile precursors to be fed to the flame. More recently, aerosol or liquid-feed flame pyrolysis (FP) allowed to overcome the low productivity problem, hence widely extending the application field of flame synthesis [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. Among the methods proposed, the spray FP seems the most interesting for the production of perovskitic oxides, since it does not require volatile precursors.…”

Synthesis and Characterization of Mixed‐Metal Oxide Nanopowders Along the CoOx–Al2O3 Tie Line Using Liquid‐Feed Flame Spray Pyrolysis

“…LF-FSP also provides access to complex mixed-metal oxide materials including mullite, Y 3 Al 5 O 12 , SrSi 2 Al 2 O 8 , and b 00 Al 2 O 3 . 38,39 In this paper, we extend our efforts to develop materials with novel phase compositions of potential interest to the catalyst and pigment industry. 36,37 In the latter arena, we have recently demonstrated that we can process materials along the TiO 2 -Al 2 O 3 , NiO-Al 2 O 3 , ZnO-Al 2 O 3 , and MgO-Al 2 O 3 tie lines with the discovery of several unusual phase compositions.…”

Synthesis, Self-assembly and Optoelectronic Properties of Monodisperse ZnO Quantum Dots

“…The ZnO films were grown on Si substrates at room temperature by RF sputtering [109]. 4 [117][118][119]. In the FSP process, the heat generated from fuel combustion was used to decompose the metalorganic precursors.…”