Synthesis of tantalum carbide and nitride nanoparticles using a reactive mesoporous template for electrochemical hydrogen evolution

Alhajri, Nawal Saad; Yoshida, Hiroshi; Anjum, Dalaver H.; Garcia Esparza, Angel T.; Kubota, Jun; Domen, Kazunari; Takanabe, Kazuhiro

Synthesis of tantalum carbide and nitride nanoparticles using a reactive mesoporous template for electrochemical hydrogen evolution

Type

Article

Authors

Alhajri, Nawal Saad

Yoshida, Hiroshi
Anjum, Dalaver H.

Garcia Esparza, Angel T.

Kubota, Jun
Domen, Kazunari
Takanabe, Kazuhiro

KAUST Department

Advanced Nanofabrication, Imaging and Characterization Core Lab
Catalysis for Energy Conversion (CatEC)
Chemical Science Program
Core Labs
Imaging and Characterization Core Lab
KAUST Catalysis Center (KCC)
Physical Science and Engineering (PSE) Division

Date

2013

Abstract

Tantalum carbide and nitride nanocrystals were prepared through the reaction of a tantalum precursor with mesoporous graphitic (mpg)-C 3N4. The effects of the reaction temperature, the ratio of the Ta precursor to the reactive template (mpg-C3N4), and the selection of the carrier gas (Ar, N2 and NH3) on the resultant crystal phases and structures were investigated. The produced samples were characterized using powder X-ray diffraction (XRD), CHN elemental analyses, thermogravimetric analyses (TGA), nitrogen sorption, a temperature-programmed reaction with mass spectroscopy (MS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The results indicate that the different tantalum phases with cubic structure, TaN, Ta2CN, and TaC, can be formed under a flow of nitrogen when formed at different temperatures. The Ta3N5 phase with a Ta5+ oxidation state was solely obtained at 1023 K under a flow of ammonia, which gasified the C 3N4 template and was confirmed by detecting the decomposed gaseous products via MS. Significantly, the formation of TaC, Ta2CN, and TaN can be controlled by altering the weight ratio of the C 3N4 template relative to the Ta precursor at 1573 K under a flow of nitrogen. The high C3N4/Ta precursor ratio generally resulted in high carbide content rather than a nitride one, consistent with the role of mpg-C3N4 as a carbon source. Electrochemical measurements revealed that the synthesized nanomaterials were consistently able to produce hydrogen under acidic conditions (pH 1). The obtained Tafel slope indicates that the rate-determining step is the Volmer discharge step, which is consistent with adsorbed hydrogen being weakly bound to the surface during electrocatalysis. © 2013 The Royal Society of Chemistry.

Citation

Alhajri, N. S., Yoshida, H., Anjum, D. H., Garcia-Esparza, A. T., Kubota, J., Domen, K., & Takanabe, K. (2013). Synthesis of tantalum carbide and nitride nanoparticles using a reactive mesoporous template for electrochemical hydrogen evolution. Journal of Materials Chemistry A, 1(40), 12606. doi:10.1039/c3ta12984e