An Effective Approach towards the Immobilization of PtSn Nanoparticles on Noncovalent Modified Multi-Walled Carbon Nanotubes for Ethanol Electrooxidation

Abstract

Abstract:In this article, we describe an effective method to tether Pt and PtSn nanoparticles (NPs) on polyelectrolyte modified multi-walled carbon nanotubes (MWCNTs) for ethanol electrooxidation. By using a polymer wrapping technique, positively charged polyethyleneimine (PEI) was attached onto carbon nanotubes (CNTs) to provide preferential linking sites for metal precursors. Well-dispersed Pt and PtSn nanocrystals (2-5 nm) were subsequently decorated on PEI-functionalized MWCNTs through the polyol reduction method. The successful non-covalent modification of MWCNTs was confirmed by Fourier transform infrared spectroscopy (FTIR) and Zeta potential measurements. Energy dispersive X-ray (EDX) spectrum indicates approximately 20 wt % Pt loading and a desirable Pt:Sn atomic ratio of 1:1. Electrochemical analysis demonstrated that the as-synthesized PtSn/PEI-MWCNTs nanocomposite exhibited improved catalytic activity and higher poison tolerance for ethanol oxidation as compared to Pt/PEI-MWCNTs and commercial Pt/XC-72 catalysts. The enhanced electrochemical performance may be attributed to the uniform dispersion of NPs as well as the mitigating of CO self-poisoning effect by the alloying of Sn element. This modification and synthetic strategy will be studied further to develop a diversity of carbon supported Pt-based hybrid nanomaterials for electrocatalysis.

Enhanced Carbon Nanotubes Growth Using Nickel/Ferrocene-Hybridized Catalyst

“…The CNT height reaches a saturation point of 34.28 μm at 860 °C. As the temperature increases further to 880 °C, the CNT height reduces to 17.4 μm due to the encapsulation of catalyst nanoparticles by hydrocarbon precipitates, as predicted by Bai et al . In contrast, the CNT height on 10 nm Ni substrate increases continuously with increase in the CVD growth temperature from 790 to 880 °C.…”

“…16 The CNT height reaches a saturation point of 34.28 μm at 860 °C. As the temperature increases further to 880 °C, the CNT height reduces to 17.4 μm due to the encapsulation of catalyst nanoparticles by hydrocarbon precipitates, 38 as predicted by Bai To further justify the improvement in CNT heights by additional Ni catalyst, we have repeated the CNT growth process on Ni catalyst of different thickness, using the obtained optimal growth temperature of 880 °C. Figure 4 presents the SEM images of the CNTs grown on 5, 20, and 30 nm Ni catalyst and the variation of obtained CNT heights on different Ni thicknesses.…”

Synthesis and Evaluation of RhxSy Catalyst with High Affinity for Nafion Ionomer for HOR/HER in a H2-Br2 Regenerative Fuel Cell

“…The GDE method, instead of the commonly used approach of coating the catalyst on a glassy carbon rotating electrode (GC-RDE), provided a more accurate determination of the catalyst mass than was needed for the accurate determination of the mass-specific surface area. [24][25][26] Finally, 3%-wt Nafion ionomer solution was brushed on the surface of the catalyst layer. The Nafion ionomer served as an ionically conductive binder for the catalyst layer.…”

Advanced Catalytic Materials for Ethanol Oxidation in Direct Ethanol Fuel Cells

“…The achieved ultrathin PtSn nanosheets exhibited an advanced mass activity of 673.6 mA mg Pt −1 in EOR, more than five times higher than commercial Pt black ( Figure 2f) [41]. This result is among the highest activity towards EOR for PtSn-alloyed electrocatalysts [45]. The outstanding catalytic performance for EOR in both acidic and alkaline media should originate from the large exposed area of (111) [40].…”