Super effective Zn-Fe-doped TiO₂nanofibers as photocatalyst for ammonia borane hydrolysis

Abstract

In this study, the photocatalytic activity of TiO 2 nanofibers toward ammonia borane hydrolysis has been strongly modified by doping the nanostructure by ZnO and Fe 2 O 3 oxides.Due to the differences in the work function and band gap energy among the three semiconductors (TiO 2 , ZnO and Fe 2 O 3 ), illumination of TiO 2 leads to accumulate the electrons and holes on the conduction and valance bands of Fe 2 O 3 and ZnO, respectively. Accordingly, the experimental results indicated that the surface of the obtained nanofibers is very active which results in an instant hydrolysis of ammonia borane molecules reaching the active zone Downloaded by [New York University] at 04:01 19 February 2015A c c e p t e d M a n u s c r i p t 2 surrounding the nanofibers. Moreover, negative activation energy was determined as increasing the temperature led to decrease the photocatalytic performance. Furthermore, kinetic studies indicated that the heterogeneous catalytic reaction describing the ammonia borane hydrolysis process is zero order which additionally supports the super activity of the introduced nanofibers.It was also observed that Fe 2 O 3 content in the introduced nanofibers has distinct influence as the best performance was obtained at 1 wt%. The modified TiO 2 nanofibers were prepared by calcination of electrospun nanofibers composed of titanium isopropoxide, zinc acetate and iron acetate in air at 700 o C for 1 h. Overall, the present study opens a new avenue to overcome the fast electrons/holes recombination dilemma facing TiO 2 -based nanostructures.

Catalytic and Photocatalytic Electrospun Nanofibers for Hydrogen Generation from Ammonia Borane Complex: A Review

“…Since that discovery, TiO 2 has continued to be researched extensively as an industrial catalytic and photocatalytic material in different applications, such as water treatment, biomedical equipment, the fine chemical industry, and energy. TiO 2 is an active, cheap, chemically inert, stable, and environmentally friendly photocatalyst with strong oxidizing powers [7,103]. However, the main issue of TiO 2 is its relatively large bandgap that prevents its effective photocatalytic activity under visible light.…”

“…TiO 2 is an active, cheap, chemically inert, stable, and environmentally friendly photocatalyst with strong oxidizing powers [ 7 , 103 ]. However, the main issue of TiO 2 is its relatively large bandgap that prevents its effective photocatalytic activity under visible light.…”

“…H 2 can be stored in high-pressure and cryogenic liquid storage tanks. Nevertheless, it is complicated to store H 2 using these tanks because it has a very low boiling point (−252.87 °C) and very low gas density (0.08988 g/L) at 1 atm [ 7 ]. The weight of the storage containers and the possibility of developing leaks are the main factors that limit storing H 2 in high-pressure tanks.…”

“…To store H 2 as a liquid, a refrigeration unit is needed to preserve the cryogenic state, which adds weight and energy costs and causes around 40% of energy loss. Furthermore, liquid or gaseous H 2 storage poses significant safety issues for on-board transport applications [ 7 ]. Solid materials with high H 2 storage and generation capacity are promising materials to overcome storage and transportation limitations.…”

“…Furthermore, the process generates undesirable byproducts. AB hydrolysis is the most promising way to generate H 2 from AB [7,[13][14][15][16]. Since 2006, the hydrolysis reaction has received substantial consideration, with special emphasis on catalytic materials [17].…”