Ethanol Electro-Oxidation on Catalysts with S-ZrO2-Decorated Graphene as Support in Fuel Cell Applications

Abstract

Direct ethanol fuel cells (DEFCs) are considered the most suitable direct alcohol fuel cell (DAFC) in terms of safety and current density. The obstacle to DEFC commercialization is the low reaction kinetics of ethanol (C2H5OH) oxidation because of the poor performance of the electrocatalyst. In this study, for the first time, graphene nanoplates (GNPs) were coated with sulfated zirconium dioxide (ZrO2) as adequate support for platinum (Pt) catalysts in DEFCs. A Pt/S-ZrO2-GNP electrocatalyst was prepared by a new process, polyol synthesis, using microwave heating. Field emission scanning electron microscope (FESEM) imaging revealed well-dispersed platinum nanoparticles supported on the S-ZrO2-GNP powder. Analysis of the Fourier transform infrared (FTIR) spectrometry confirmed that sulfate modified the surfaces of the sample. In X-ray diffraction (XRD), no effect of S-ZrO2 on the crystallinity net in Pt was found. Pt/S-ZrO2-GNP electrode outperformed those with unsulfated counterparts, primarily for the higher access with electron and proton, confirming sulfonating as a practical approach for increasing the performance, electrocatalytic activity, and carbon monoxide (CO) tolerance in an electrocatalyst. A considerable decrease in the voltage of the CO electrooxidation peak from 0.93 V for Pt/C to 0.76 V for the Pt/S-ZrO2-GNP electrode demonstrates that the new material increases activity for CO electrooxidation. Moreover, the as-prepared Pt/S-ZrO2-GNPs electrocatalyst exhibits high catalytic activity for the EOR in terms of electrochemical surface area with respect to Pt/ZrO2-GNPs and Pt/C (199.1 vs. 95 and 67.2 cm2.mg−1 Pt), which may be attributed to structural changes caused by the high specific surface area of graphene nanoplates catalyst support and sulfonating effect as mentioned above. Moreover, EIS results showed that the Pt/S-ZrO2-GNPs electrocatalyst has a lower charge transfer resistance than Pt/ ZrO2-GNPs and Pt/C in the presence of ethanol demonstrating an increased ethanol oxidation activity and reaction kinetics by Pt/S-ZrO2-GNPs.

Enhanced Mass Activity and Durability of Bimetallic Pt-Pd Nanoparticles on Sulfated-Zirconia-Doped Graphene Nanoplates for Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cell Applications

“…This indicates that the addition of zirconia through the adopted method does not introduce specific functional groups to the surface of the GNPs [61,62]. The FTIR results of GO and ZrO2-graphene nanoplates and sulfated zirconia-GNPs were presented in our previously published work [63]. 220), (200), and (111) diffraction peaks of the crystal surface, respectively, showing that it is a disordered Pt-Pd alloy.…”

“…This reflection was chosen for the Scherrer examination due to its high-strength level. This formula can be defined as follows [70]: The FTIR results of GO and ZrO 2 -graphene nanoplates and sulfated zirconia-GNPs were presented in our previously published work [63].…”

“…The importance of the surface oxygen source for the effective O 2 reduction in fuel cell electrocatalysts has been highlighted in the case of carboncoated tungsten oxides [82]. ZrO 2 is a well-known reducible oxide that shows high oxygen storage capacity and strong metal support interaction between Pt and ZrO 2 [63,[83][84][85]. The overall reaction mechanism for oxygen reduction on the Pt-Pd/S-ZrO 2 -GNP electrode can be proposed as follows:…”

Synthesis and Study of Palladium Mono- and Bimetallic (with Ag and Pt) Nanoparticles in Catalytic and Membrane Hydrogen Processes

“…Nanoparticles are most widely used in medicine [ 23 , 24 ], spectroscopy [ 25 , 26 ], catalysis [ 27 , 28 ], and energy [ 29 , 30 ]. Catalysis and energy fields are of main interest in this paper, since the development of advanced catalysts based on metal nanoparticles with improved activity, selectivity and stability is an important and relevant task [ 31 , 32 , 33 ].…”

Application of Graphene-Based Materials

“…In this work, the authors demonstrated that it is possible to tailor and control the performance of graphene-based anodes in boron ion batteries by increasing the number of graphene layers, reaching cell voltage values that enable the practical use of these batteries, even as replacers of the more common Li ion ones. Yaldagard and co-workers [4] used coated graphene nanoplatelets as supporters for platinum electrocatalysts in direct ethanol fuel cells, and demonstrated the high activity of the Pt-coated graphene material for CO electrooxidation, its high catalytic activity for the EOR, and its lower charge transfer resistance in the presence of ethanol (i.e., enhanced ethanol oxidation activity), all essential aspects in this kind of fuel cell.…”