Platinized titanium nitride/graphene ternary hybrids for direct methanol fuel cells and titanium nitride/graphene composites for high performance supercapacitors

Abstract

A titanium nitride/reduced graphene oxide nanocomposite (TiN/rGO) was fabricated by a two-step process. The resulting TiN particles had a mean diameter of less than 10 nm and were densely decorated onto the rGO surface. The TiN/rGO composite was used as a support matrix to anchor platinum (Pt) nanoparticles by the polyol method to fabricate a Pt@TiN/rGO ternary hybrid catalyst for methanol oxidation. An increase in the methanol oxidation current density was observed for Pt@TiN/rGO when compared to Pt/rGO and Pt/Vulcan, confirming that the inclusion of TiN along with rGO improved the electrocatalytic activity. The electrochemical surface area was also significantly higher for the Pt@TiN/ rGO catalyst (84.5 m(2) g(-1)) than for Pt/rGO (51.7 m(2) g(-1)) and Pt/Vulcan (33.7 m(2) g(-1)), highlighting the importance of TiN. The Pt@TiN/rGO hybrid showed excellent electrocatalytic activity, long-term stability, and better carbon monoxide tolerance for the electrooxidation of methanol when compared to more traditional catalysts, namely Pt/rGO and Pt/Vulcan with same Pt content. Conversely, the TiN/rGO composite (without Pt) showed a higher capacitance of 415 F g(-1) and a long cycle life, with 7.0% capacitance loss after 10,000 cycles. The capacitance was as high as 275 F g(-1) at a current density of 5 A g(-1). (C) 2016 Elsevier Ltd. All rights reserved.