Catalytic Intervention of MoO₃toward Ethanol Oxidation on PtPd Nanoparticles Decorated MoO₃–Polypyrrole Composite Support

Abstract

Ethanol oxidation reaction has been studied in acidic environment over PtPd nanoparticles (NPs) grown on the molybdenum oxide–polypyrrole composite (MOPC) support. The attempt was focused on using reduced Pt loading on non-carbon support for direct ethanol fuel cell (DEFC) operated with proton exchange membrane (PEM). As revealed in SEM study, a molybdenum oxide network exists in polypyrrole caging and the presence of metal NPs over the composite matrix is confirmed by TEM analysis. Further physicochemical characterizations such as XRD, EDAX, and XPS are followed in order to understand the surface morphology and composition of the hybrid structure. Electrochemical techniques such as voltammetry, choroamperometry, and impedance spectroscopy along with performance testing of an in-house-fabricated fuel cell are carried out to evaluate the catalytic activity of the materials for DEFC. The reaction products are estimated by ion chromatographic analysis. Considering the results obtained from the above characterization procedures, the best catalytic performance is exhibited by the Pt–Pd (1:1) on MOPC support. A clear intervention of the molybdenum oxide network is strongly advocated in the EOR sequence which increases the propensity of the reaction by making the metallites more energy efficient in terms of harnessing sufficient numbers of electrons than with the carbon support.

Tailored Electron Transfer Pathways in Aucore/Ptshell–Graphene Nanocatalysts for Fuel Cells

“…The anodic peak at 0.7 V represents the reaction pathway via CO ads oxidation where G-Cys-Au@Pt exhibits 406 mA mg Pt −1 , and 3.8 times larger currents than those obtained with C-Pt and greatly improved stability with currents 4.4 times higher after 6000 s of continuous reaction, Figure 5E,F. [55,56] FAOR, MOR, and EOR experiments were performed on G-Au@Pt, Figure S17 (Supporting Information). Akhairi and Kamarudin reported the significance of fuel concentration on the FC performance, showing 4 times higher current densities for EOR in 1.0 m compared to 0.10 m ethanol with a Pt/C catalyst.…”

Nanocatalysts for Electrocatalytic Oxidation of Ethanol

“…[213] They synthesized WCÀPd nanocomposites on graphene, in which small-sized Pd nanoparticles were decorated on the surfaceso fW C. Both DFT calculations and Xray photoelectrons pectroscopy( XPS) measurements confirm that there is as trong interaction betweenP da nd WC domains, which results in electron transfer from WC to Pd in the WCÀPd nanocomposites. [217][218][219][220][221][222][223][224][225][226][227][228][229][230][231][232] The enhanced EOR is derived first from surfaces rich in oxygen-containing species providedb yt he metal oxides, which are capable of removing adsorbed poisonous CO intermediates by facilitating oxidation to CO 2 .S econd, the "OH carpet" created by metal oxidesc ould precludeP t, Pd, or their alloys with other metals (e.g.,R h, Ru) from reacting with water to form compounds with ÀOH species, making them in lowcoordination states and available for ethanol oxidation. Electron transfer from WC to Pd in the nanocomposites not only modifies the electronic structure of the Pd domain,w hich is favorable for the scission of ethanol molecules on Pd sites, but also weakenst he adsorption of poisoning intermediates, such as CO, on the Pd surface by increasing the electron density around Pd atoms.…”

“…[215,216] Noble metals, such as Pt and Pd, werec onventionally integratedw ith transition-metal oxidest of orm nanocomposites to enhancet heir electrocatalytic performance in the EOR. [217][218][219][220][221][222][223][224][225][226][227][228][229][230][231][232] The enhanced EOR is derived first from surfaces rich in oxygen-containing species providedb yt he metal oxides, which are capable of removing adsorbed poisonous CO intermediates by facilitating oxidation to CO 2 .S econd, the "OH carpet" created by metal oxidesc ould precludeP t, Pd, or their alloys with other metals (e.g.,R h, Ru) from reacting with water to form compounds with ÀOH species, making them in lowcoordination states and available for ethanol oxidation. [200] The use of ac onducting polymer, [233,234] transition-metal phosphate, [235,236] and silicon, [237] to form nanocomposites with Pt or Pd for promoting their electrocatalytic activity for the EOR has also been reported.…”

The influence of ZrO2promoter in Pd/fCNDs-ZrO2catalyst towards alcohol fuel electrooxidation in alkaline media

“…These fuels are ecofriendly because their electrooxidation reactions produce water and a substantially low amount of carbon dioxide gas as by-products [1,2]. Direct methanol and ethanol fuel cells continue to attract attention due to high power densities (6.09 kW h kg −1 for methanol and 8.01 kW h kg −1 for ethanol) which can be harvested directly from these fuels [2,3]. Ethanol is more attractive than methanol owing to its non-toxicity and abundance [3].…”

“…Direct methanol and ethanol fuel cells continue to attract attention due to high power densities (6.09 kW h kg −1 for methanol and 8.01 kW h kg −1 for ethanol) which can be harvested directly from these fuels [2,3]. Ethanol is more attractive than methanol owing to its non-toxicity and abundance [3]. Despite the toxicological issues associated with methanol, it is much easier to oxidize because each methanol molecule has five bonds only which need to be cleaved during electrooxidation reactions compared to eight bonds in one ethanol molecule [4].…”