TiN nanotube supported Ni catalyst Ni@TiN-NTs: experimental evidence of structure-activity relations in catalytically hydrolyzing ammonia borane for hydrogen evolution

Yawei Liu; Jun Zhang; Quanxing Liu; Xiang Li

doi:10.1039/d0ra06920e

TiN nanotube supported Ni catalyst Ni@TiN-NTs: experimental evidence of structure-activity relations in catalytically hydrolyzing ammonia borane for hydrogen evolution

RSC Adv. 2020 Oct 8;10(61):37209-37217. doi: 10.1039/d0ra06920e. eCollection 2020 Oct 7.

Authors

Yawei Liu¹, Jun Zhang¹, Quanxing Liu¹, Xiang Li¹

Affiliation

¹ Chemical Engineering & Pharmaceutics School, Henan University of Science & Technology Luoyang 471023 China j-zhang@126.com.

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 TiN _x O _y 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.