Diamond Nanoparticles as a Support for Pt and PtRu Catalysts for Direct Methanol Fuel Cells

Abstract

Diamond in nanoparticle form is a promising material that can be used as a robust and chemically stable catalyst support in fuel cells. It has been studied and characterized physically and electrochemically, in its thin film and powder forms, as reported in the literature. In the present work, the electrochemical properties of undoped and boron-doped diamond nanoparticle electrodes, fabricated using the ink-paste method, were investigated. Methanol oxidation experiments were carried out in both half-cell and full fuel cell modes. Platinum and ruthenium nanoparticles were chemically deposited on undoped and boron doped diamond nanoparticles through the use of NaBH(4) as reducing agent and sodium dodecyl benzene sulfonate (SDBS) as a surfactant. Before and after the reduction process, samples were characterized by electron microscopy and spectroscopic techniques. The ink-paste method was also used to prepare the membrane electrode assembly with Pt and Pt-Ru modified undoped and boron-doped diamond nanoparticle catalytic systems, to perform the electrochemical experiments in a direct methanol fuel cell system. The results obtained demonstrate that diamond supported catalyst nanomaterials are promising for methanol fuel cells.

Diamond Nanostructures and Nanoparticles: Electrochemical Properties and Applications

“…Different kinds of diamond nanoparticles (e.g., surface graphitized diamond nanoparticles with a diamond core covered by a graphitic carbon shell, bucky diamond nanoparticles with a nanoscale diamond core surrounded by a fullerene shell, and graphene coated diamond nanoparticles) have been used as the support to load catalysts (e.g., Pt [87][88][89][90][91][92][93], Ni [94,95], Ti [96], Pd [97], Pt/Ni [98], Pt/Ru [99][100][101][102], Sn/Pb [103], Pt/Eu [91,99], and metal oxides [104][105][106]). The mostly investigated electrocatalytic reactions include electrocatalytic oxidation of methanol/formic acid/CO as well as oxygen reduction reaction.…”

“…The mostly investigated electrocatalytic reactions include electrocatalytic oxidation of methanol/formic acid/CO as well as oxygen reduction reaction. To load these catalysts on diamond nanoparticles, numerous approaches have been developed, including electrodeposition [88,92], chemical reduction [93], and microwaveassisted polyol synthesis [91,99]. For example, electrodeposition of Pt nanoparticles on un-doped diamond nanoparticles (5-100 nm in diameter) were conducted in 1.1 mM chloroplatinic acid solution.…”

“…The electrodeposited Pt nanoparticles were well-dispersed on the facet surfaces of diamond nanoparticles [88,107]. Pt and Ru nanoparticles were chemically deposited on un-doped and boron-doped diamond nanoparticles through the use of NaBH 4 as reducing agent and sodium dodecyl benzene sulfonate as a surfactant [93]. Microwave-assisted reduction method [91,98] has been used for the preparation of catalysts of Pt [91], Pt/Ni [98], and Pt/Ru [102] on the surface of diamond nanoparticles.…”

“…The Pt/Ru nanoparticles were small and uniform with the size of 2-4 nm, and highly dispersed on the surface of diamond nanoparticles [102]. A simple ultrasonic treatment in the presence of diamond powders prior to electrodeposition improved spatial distribution and a higher Pt dispersion over the electrode [99][100][101][102]. A two-step method was reported to modify diamond nanoparticles with Pt and TiO 2 nanoparticles, namely first by a microwave hydrolysis step, and then electrodeposition of Pt nanoparticles [104][105][106].…”

Modified Diamond Electrodes for Electrochemical Systems for Energy Conversion and Storage

“…The route used to prepare the suspensions (inks) of DNPs and BDDNPs for the electrochemical studies performed by La-Torre-Riveros and co-workers [63] shown to be well suitable to obtain useful electrochemical information on these nanoparticle diamond supported systems. The cyclic voltammetry results showed that there were significant differences between the undoped DNP and BDDNPs samples, with the latter exhibiting superior characteristics in terms of various electrochemical applications, including that of catalyst support.…”