Abstract
With commercial TiO2 as the precursor, titanium nitride nanotubes (TiN-NTs) were fabricated through a hydrothermal – ammonia nitriding route, and next non-noble metal nanosized Ni particles were evenly and firmly anchored on the surface of the TiN-NTs via a PVP-mediated non-aqueous phase reduction–deposition strategy, to obtain the supported catalyst Ni@TiN-NTs. The X-ray powder diffraction (PXRD), field emission scanning and transmission electron microscopy (FE-SEM/TEM) and specific surface area measurements were used to characterize and analyze the phase composition, surface microstructure and morphological features of the product. The catalytic activity of the Ni@TiN-NTs for hydrolyzing ammonia borane to generate hydrogen (H2) under different conditions was evaluated systematically. The results reveal that the as-fabricated TiN-NTs are composed of TiN and a small amount of TiNxOy with the approximate molar atomic ratio of Ti to N at 1 : 1, existing as hollow microtubules with mean tube diameter of 130 nm and length of about 1 μm. Via in situ reduction and deposition, Ni nanoparticles can be uniformly anchored on the surface of TiN-NTs. The catalytic activities of Ni(x)@TiN-NTs with different Ni loading amounts are all higher than that of single metal Ni nanoparticles. The temperature has a positive effect on the catalytic activity of Ni(20)@TiN-NTs, and its total turnover frequency for hydrolyzing ammonia borane is 11.73 mol(H2) (mol Ni)−1 min−1, with an apparent activation energy of 52.05 kJ mol−1 at 303 K. After 5 cycles, the Ni(20)@TiN-NTs catalyst still maintains 87% of the initial catalytic activity. It could be suggested that these tactics can also be extended to the fabrication of other metal or alloy catalysts supported by TiN-NTs, with great application potential and development prospects.
Highlights
With commercial TiO2 as the precursor, titanium nitride nanotubes (TiN-NTs) were fabricated through a hydrothermal – ammonia nitriding route, and non-noble metal nanosized Ni particles were evenly and firmly anchored on the surface of the Titanium nitride (TiN)-NTs via a PVP-mediated non-aqueous phase reduction– deposition strategy, to obtain the supported catalyst Ni@TiN-NTs
Based on the above cognition and analysis for the structure–activity relationship of the TiN-NTs, via elaborately designing the hydrothermal treatmentnitriding synthesis route, we rst fabricated TiN-NTs microarchitectures with regular pro les; and by way of the solvothermal reduction-deposition tactics that was in situ mediated by PVP, non-noble metal Ni nanoparticles were dispersed and immobilized on the TiN-NTs surface, to obtain highly efficient and low-cost Ni@TiN-NTs supported catalyst with no noble metals contained
Under a certain temperature and pressure condition, hydrogen (H2) amount generated by catalytic hydrolysis of ammonia borane (AB) in unit time can be accurately measured, which could be used to evaluate the catalytic activity of the relevant catalysts
Summary
Titanium dioxide (TiO2, 99%), nitric acid (HNO3, 65%), sodium hydroxide (NaOH, 98%), ethylene glycol ((CH2OH)[2], EG, 99%), nickel chloride (NiCl2$6H2O, 98%), hydrazine hydrate (N2H4$H2O, 85%), absolute ethyl alcohol (C2H5OH, 98%) and polyvinylpyrrolidone (PVP, Mw 1⁄4 1 Â 104), are pure analytical reagents purchased from Shanghai Sinopharm Group and used directly without further puri cation. The phase structure of the serial products was analyzed by X-ray powder diffraction (PXRD) (Advance-D8, Bruker, Germany). Their morphologies were minutely investigated by eld emission scanning electron microscopy (FE-SEM) (JEM-2100, JEOL, Japan) and transmission electron microscopy (TEM) (JEM 2100, Hitachi, Japan). The precipitate was thermally treated in a program control furnace at 400 C for 2 h, so as to be transformed to the anatase phase TiO2-NTs. Placing the TiO2NTs in a tube furnace, followed by inletting nitrogen gas to the tube for 20 min to remove the air, the tube furnace was heated to 500 C at a heating rate of about 5 C minÀ1, staying at this temperature for 10 min. At the temperature (850 C) the reaction in the furnace was maintained for 3 h, followed by the natural cooling to room temperature, and the resulting product, or titanium nitride nanotube particles (TiN-NTs), could be harvested
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
