Loading...

Preparation of new titanium nitride-carbon nanocomposites in supercritical benzene and their oxygen reduction activity in alkaline medium

Yousefi, E ; Sharif University of Technology | 2015

1192 Viewed
  1. Type of Document: Article
  2. DOI: 10.1016/j.electacta.2015.02.199
  3. Publisher: Elsevier Ltd , 2015
  4. Abstract:
  5. Titanium nitride-carbon nanocomposites are synthesized by the reaction of TiCl4 and NaN3 in supercritical benzene medium that also serves as a carbon source. The as-prepared precursors (SI, SII) are subjected to several heat treatments (SIII-SV). The synthesized nanoparticles are characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The samples are tested as electrocatalyst for oxygen reduction reaction in an alkaline electrolyte. It is shown that the electrocatalytic properties of the synthesized nanoparticles are highly dependent on the heat treatment atmosphere and duration. The heat treatment under ammonia atmosphere at 1000 °C for 10 h (SIV) increased the ORR mass activity from -0.64 (SI) to -1.28 mA mg-1 (SIV) at -0.6 V vs. SCE. Moreover, the heat treated sample (SIV) shows almost twice ORR mass activity as commercial TiN. Rotating disk electrode (RDE) measurements exhibit ORR on commercial TiN proceeds via two parallel pathways including two and four electrons, resulting in almost 60% H2O2 production, while SIV sample improves ORR by reducing H2O2 formation to almost 16%. The high ORR activity and stability of the sample SIV are mainly due to (i) random layer structure of carbon that combines through a hybrid state with TiN nanoparticles, (ii) unstoichiometric nitrogen and oxygen doped into TiN lattice, and (iii) higher electrochemical surface area. Moreover, the possible pathways of carbon phase formation in vicinity of supercritical reaction are discussed
  6. Keywords:
  7. Supercritical benzene ; Titanium nitride-carbon nanocomposite ; Benzene ; Carbon ; Carbon nitride ; Electrocatalysts ; Electrolytic reduction ; Electron microscopy ; Enamels ; Field emission microscopes ; Fourier transform infrared spectroscopy ; Heat treatment ; Nanocomposites ; Nanoparticles ; Nitrides ; Oxygen ; Reduction ; Rotating disks ; Scanning electron microscopy ; Synthesis (chemical) ; Titanium ; Titanium compounds ; Transmission electron microscopy ; X ray diffraction ; X ray photoelectron spectroscopy ; Carbon nanocomposite ; Electrocatalyst for oxygen reduction reactions ; Electrocatalytic properties ; Electrochemical surface area ; Field emission scanning electron microscopy ; Oxygen reduction reaction ; Rotating disk electrodes ; Supercritical ; Titanium nitride
  8. Source: Electrochimica Acta ; Volume 164 , May , 2015 , Pages 114-124 ; 00134686 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0013468615005216