Diffusion-limited reduction of organometallic compound on carbon nanofiber mat for catalytic applications

Abstract

We propose a simple and efficient method of synthesizing highly electrocatalytic Pt nanoparticles on a carbon nanofiber mat. Pt(acac)₂ molecules are absorbed on the functionalized carbon nanofibers and further reduced to Pt nanoparticles by diffusion-limited sublimation in a confined space. Pt nanoparticles are formed with sizes of 2.9 ± 0.4 nm and 100% loading yield. By further electrochemical activation via a cyclic voltammetry, high active surface area of Pt nanoparticles is obtained due to the formation of specific crystalline facets. The methanol oxidation current density per mg Pt of Pt-loaded carbon nanofiber sample is about 60 times as high as the commercially available (E-tek) sample and superior to other existing samples. The Pt-loaded carbon nanofiber mat is used as an anode in a microbial fuel cell application. The activated Pt nanoparticles chaperon the electron transport from the bacterial matrix to the carbon nanofiber mat. The electrochemically activated electrode shows a significantly higher current density (0.6 A m⁻²) than the untreated sample and higher than an e-beam deposited Pt/carbon microfiber paper. The long-term stability at this current is four times (150 hours) longer than the reported values. We believe that this method can be practically applied to load the organometallic compound-based catalyst on various carbon-based supports.