Enhanced Hydrogen Production from Ammonia Borane over Ni Nanoparticles Supported on TiN–TiO₂ Composites under Sunlight

Abstract

Titanium dioxide–titanium nitride composite (TiO2–TiN) nanoparticles (NPs) were used as a support to load nickel nano particles for the dehydrogenation of ammonia borane (AB) which is a new method. The composite support was fabricated via a simple ultrasonic mixing route, followed by the in situ loading of Ni NPs using a liquid-phase reduction reaction method where sodium borohydride was adopted as a reducing agent. The synthesized samples were characterized by X-ray diffraction spectra (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Ultra Violet-Visible (UV–vis) analyses. The characterization results show that the Ni NPs uniformly dispersed on the support and existed in both zero and oxidized states. Compared with bare TiO2, Ni loading on TiO2–TiN exhibited a higher catalytic activity toward dehydrogenation of AB both under dark and under sunlight irradiation. Ni/10%TiN–TiO2 showed a hydrogen evolution rate with a turnover frequency (TOF) of 8.01 molH2 ·min–1·molcat –1 at 25 °C under sunlight. The loading of Ni NPs lowered the band gap energy of TiO2, resulting in the enhanced absorption of sunlight. The addition of TiN that acts as electron scavengers improved the separation efficiency of electron–hole pairs. Titanium dioxide–titanium nitride composites play an important role in improving the catalytic dehydrogenation of AB by nickel-based catalysts.

Review on Hydrogen Production from Catalytic Ammonia Borane Methanolysis: Advances and Perspectives

“…In recent years, the research on hydrogen production of AB at normal temperature has mainly been focused on catalytic AB hydrolysis. − In particular, the catalytic hydrolysis performance and mechanism of AB have been well-investigated. According to the mechanism of hydrogen production via catalytic hydrolysis of AB reported in the literature, there is a special force between the boron–nitrogen coordination bond of the AB molecule and the surface of the metal catalyst.…”

Scaling up the charge transfer on Pd@Ti3C2Tx–TiO2 catalysts: a sustainable approach for H2 generation via water splitting

“…26 The employment of cocatalysts on TiO 2 has been found to be more effective for sustainable water splitting. 27,28 Cocatalysts with the ability to quench the electrons from semiconductor systems can be effective for excellent charge transportation, specifically in water-splitting reactions. 29,30 The higher charge separation ability of the cocatalyst is attributed to its chemical properties (i.e., conductivity and stability).…”