Facile Decoration of Platinum Nanoparticles on Carbon-Nitride Nanotubes via Microwave-Assisted Chemical Reduction and Their Optimization for Field-Emission Application

This study reports a simple, efficient method of using Pt manoparticiles to decorate CNx nanotubes with controllable particle size and population density. CNs nanotubes, synthesized by the chemical vapor deposition of an imidazoleferrocene mixture at 750 degrees C, were dispersed in 2-(2-methoxyethoxy)-ethanol sovent together with H2PtCl6. The reduction of Pt(IV) to Pt(0) was achieved with NaBH4 and microwave irradiation, separately. The NaBH4 mediated reduction process reuslt in Pt manopartciles of small size decorating the CNx surface with low density. However, microwave-assited chemical reduction leads to larger nanoparticles with a high population density. It is observed that Pt-anchoring on the CNx strands is mainly governed by pyridinc-N (pN) units. The XPS peak intensities of Pt(II) and Pt(IV) are very low when Pt nanoparticles are grown via microwave-irradiation process, as compared to the NaBH4 reduction process. This suggests that NaBH4 treatment leads to the incomplete reduction of Pt ions. In contrast, microwave irradiation not only offer complete Pt reduction but also enables control of the particles size and density as a function of the irradiation time. Moremover, the field-emission (FE) performance is found to increaes with increasing irradiation time. The field enchancement factor of the longest microwave-irradiated (110s) sample increased 5-fold as compared to that of the beare CNx sample. This is the first experimental evidance of the FE enhancement of platinum-decorated CNx nanotubes.