Atomic layer deposition of Ti-Nb-O thin films onto electrospun fibers for fibrous and tubular catalyst support structures

Abstract

Here, the authors report on the preparation of core-shell carbon-ceramic fibrous as well as ceramic tubular catalyst supports utilizing electrospinning and atomic layer deposition (ALD). In this paper, ALD of Ti-Nb-O thin films using TiCl 4 , Nb(OEt) 5 , and H 2 O as precursors is demonstrated. According to the time-of-flight-elastic recoil detection analysis and Rutherford backscattering spectrometry, carbon and hydrogen impurities were relatively low, but depend on the pulsing ratio of the precursors. Optimized ALD process was used for coating of sacrificial electrospun polyvinyl alcohol (PVA) template fibers to yield tubular Ti-Nb-O structures after thermal or solution based PVA removal. Another approach utilized 200-400 nm thick carbon fibers prepared by electrospinning from polyacrylonitrile and subsequent thermal treatment.

HOR Activity of Pt-TiO2-Y at Unconventionally High Potentials Explained: The Influence of SMSI on the Electrochemical Behavior of Pt

“…Direct Pt deposition on the carbon fiber support is excluded here, as the ALD-deposited TiO 2 fully covers the carbon support as shown in a previous study. 37 The upper left image in Fig. 1 shows that the Pt nanoparticles have been successfully formed by 10 Pt ALD cycles (10#Pt) onto the oxide support.…”

“…Synthesis and physicochemical characterization.-Synthesis of the catalyst support.-Synthesis and in-depth analysis of the oxide support has recently been described elsewhere 37 and is given briefly here. Polyacrylonitrile fibres sheets were electrospun using N,Ndimethylformamide (DMF) as solvent.…”

Platinum Sputtered on Nb-doped TiO2 Films Prepared by ALD: Highly Active and Durable Carbon-free ORR Electrocatalyst

“…Nb-doped TiO 2 thin films were grown on the substrates by atomic layer deposition (ALD) in a home-built ALD reactor at 250 °C using niobium(V) ethoxide (Nb(OEt) 5 ), titanium(IV) chloride, and water vapors as precursors, following the procedure similar to that reported recently. 45,46 TiCl 4 (Sigma-Aldrich, 99.9% trace metal basis) and deionized H 2 O were vaporized in reservoirs kept outside the reactor at room temperature. The precursor flows were controlled by a capillary and a needle valve, respectively, and carried into the deposition zone separately and alternately by dry inert gas (N 2 , 99.999%).…”

ALD coating of centrifugally spun polymeric fibers and postannealing: case study for nanotubular TiO2 photocatalyst

“…These results contrast with the early reports for coated electrospun fibers, where the annealing process of ALD TiO 2 coated polymeric fibers did not yield such a significant change in the diameter of the resulting hollow tubular structures. 11,[42][43][44][45][46] Namely, Kim et al 11 coated electrospun PVP fibers with diameters of around 500 nm with TiO 2 by ALD applying 1000 cycles and the resulting TiTBs largely maintained the initial diameters with a wall thickness of ≈60 nm. De Dicastillo et al 45 coated electrospun PVA fibers with TiO 2 by ALD by applying 250 and 500 ALD cycles and annealed them at temperatures of 400 °C and 600 °C.…”

“…38 Among the synthetic polymers, poly(vinyl pyrrolidone) PVP and poly(vinyl alcohol) PVA are most widely used due to their facile preparation in water as solvents. [39][40][41] The electrospun polymer fibers were subsequently coated by ALD with TiO 2 , 11,[42][43][44][45][46] Al 2 O 3 10,47-49 or ZnO. 44,[50][51][52][53] In all aforementioned reports the diameters of the electrospun fibers were limiting the diameters of the resulting nanotubes to the range between tens and few hundreds of nm.…”