Ethanol electro-oxidation

It is well established that the main products of ethanol electro-oxidation on Pt in acidic media are acetaldehyde and acetic acid, partial oxidation products that do not require C—C bond breaking, with their relative yields depending on the experimental conditions [Iwasita and Pastor, 1994]. Apart from the loss of efficiency associated with the partial oxidation, acetic acid is also unwanted, as it constitutes a catalyst poison. [Pg.192]

Infrared spectroscopy has also been employed to follow the formation of acetaldehyde and acetic acid on Pt during ethanol electro-oxidation. On the basal planes, acetaldehyde could be observed starting at about 0.4 V (vs. RHE), well before the onset of CO oxidation, while the onset of acetic acid formation closely follows CO2 formation [Chang et al., 1990 Xia et al., 1997]. This is readily explained by the fact that both CO oxidation and acetic acid formation require a common adsorbed co-reactant, OHads, whereas the formation of acetaldehyde from ethanol merely involves a relatively simple proton-electron transfer. [Pg.194]

Another metal that has attracted interest for use as electrode material is rhodium, inspired by its high activity in the catalytic oxidation of CO in automotive catalysis. It is found that Rh is a far less active catalyst for the ethanol electro-oxidation reaction than Pt [de Souza et al., 2002 Leung et al., 1989]. Similar to ethanol oxidation on Pt, the main reactions products were CO2, acetaldehyde, and acetic acid. Rh, however, presents a significant better CO2 yield relative to the C2 compounds than Pt, indicating a... [Pg.195]

Finally, trimetallic compounds have been developed to enhance the electroactivity of Pt-based catalysts, for either methanol or ethanol electro-oxidation. A long time ago, it was reported that adsorption of molybdates (Na2Mo04) at a Pt black electrode... [Pg.352]

The addition of Sn to Pt increases the activity of ethanol electro-oxidation and single DEFC performance [Rousseau et al., 2006 Zhou et al., 2004a Vigier... [Pg.356]

TABLE 11.2 Chemical Yields in Acetic Acid, Acetaldehyde, and CO2 for Pt/C and Pt-Sn (9 1)/C Catalysts during Ethanol Electro-oxidation under DEFC Operating Conditions at 80 "C for 4 Honrs ... [Pg.358]

At this stage, it should be pointed out that modihcation of a Pt-Sn catalyst by Ru atoms increases cell performance (and hence catalytic activity with regard to ethanol electro-oxidation), but has no effect on the OCV or on product distribution [Rousseau et al., 2006]. It seems, then, that the oxidation mechanism is the same on Pt-Sn and Pt-Sn-Ru, which supports the proposition that Ru allows OH species to be produced when the anode potential is increased and noncatalytically active tin oxides are formed. [Pg.359]

Vigier F, Coutanceau C, Hahn F, Belgsir EM, Lamy C. 2004a. On the mechanism of ethanol electro-oxidation on Pt and PtSn catalysts Electrochemical and in situ IR reflectance spectroscopy studies. J Electroanal Chem 563 81-89. [Pg.372]

In this chapter, two carbon-supported PtSn catalysts with core-shell nanostructure were designed and prepared to explore the effect of the nanostructure of PtSn nanoparticles on the performance of ethanol electro-oxidation. The physical (XRD, TEM, EDX, XPS) characterization was carried out to clarify the microstructure, the composition, and the chemical environment of nanoparticles. The electrochemical characterization, including cyclic voltammetry, chronoamperometry, of the two PtSn/C catalysts was conducted to characterize the electrochemical activities to ethanol oxidation. Finally, the performances of DEFCs with PtSn/C anode catalysts were tested. The microstmc-ture and composition of PtSn catalysts were correlated with their performance for ethanol electrooxidation. [Pg.310]

Several added metals were investigated to improve the kinetics of ethanol oxidation at platinum-based electrodes, including ruthenium [27, 28], lead [29] and tin [22, 30]. Of these, tin appeared to be very promising. Figure 1.11 shows the polarization curves of ethanol electro-oxidation recorded at a slow sweep rate (5 mV s ) on different platinum-based electrodes. Pt-Sn(0.9 0.1)/C displays the... [Pg.25]

V vs. RHE in agreement with previous studies by DBMS, infrared spectroscopy and gas chromatography. Moreover, Iwasita and Pastor have detected some traces of methane at low potentials. From prolonged electrolysis experiments and in situ infrared reflectance spectroscopy, the main reaction products and intermediates involved in ethanol electro-oxidation on a platinum catalyst have been determined CO and CH3CO species as adsorbed intermediates, CH3CHO as intermediate and final product, CH3COOH, CO2 and CH4 as final products. [Pg.456]

SPAIR spectra obtained on Pt and PtSn catalysts during ethanol electro-oxidation (Figs. 32 and 33) show that CO2 (wave-number of the absorption band located at 2345 cm ) is only detected at 0.6 V vs. RHE on both Pt and on PtSn catalysts. But, as shown in Fig. 34a, the intensity of the CO2 IR band is higher for PtSn than for Pt at potentials lower than 0.65 V vs. RHE. It is likely that in the detection limit of the IR set up it is difficult to detect CO2 at lower potentials on a PtSn electrode. [Pg.458]

Besides, it has been shown that palladium is promising for direct alcohol fuel cells applications as it is very active for ethanol electro-oxidation in basic media and that its electroactivity is even higher than that of platinum. Recently, Pd nanoballs and nanowires synthesized by radiolysis in hexagonal mesophases have shown an important elec-trocatalytic activity for ethanol electro-oxidation. ... [Pg.368]

Silva JCM, Parreira LS, De Souza RFB, Calegaro ML, Spinace EV, Neto AO, Santos MC (2011) PtSn/C alloyed and non-alloyed materials differences in the ethanol electro-oxidation reaction pathways. Appl Catal B Environ 110 141-147... [Pg.76]

Gomes JF, Busson B, Tadjeddine A, Tremiliosi G (2008) Ethanol electro-oxidation over Pt QiM). comparative study on the reaction intermediates probed by FTIR and SFG... [Pg.97]

Lai SCS, Kleijn SEF, Ozturk FTZ, Vellinga VCV, Koning J, Rodriguez P, Koper MTM (2010) Effects of electrolyte pH and composition on the ethanol electro-oxidation reactitm. Catal... [Pg.97]

Similar steps can be drawn for the case of ethanol electro-oxidation [22], in which the total electrochemical oxidation of ethanol, involving 12 electrons, can be represented by ... [Pg.105]

Tusi MM, Polanco NSO, da Silva SG, Spinace EV, Neto AO (2011) The high activity of PtBi/ C electrocatalysts for ethanol electro-oxidation in alkaline medium. Electrochem Commun 13(2) 143-146... [Pg.124]

Qi Z, Geng H, Wang X, Zhao C, Ji H, Zhang C, Xu J, Zhang Z (2011) Novel nanocrystalline PdNi alloy catalyst for methanol and ethanol electro-oxidation in alkaline media. J Power Sources 196 5823-5828... [Pg.153]

Nguyen ST, Yang Y, Wang X (2012) Ethanol electro-oxidation activity of Nb-doped-Ti02 supported PdAg catalysts in alkaline media. Appl Catal B Environ 113(114) 261-270... [Pg.154]

Wang X, Wang W, Qi Z, Zhao C, Ji H, Zhang Z (2012) Novel Raney-like nanoporous Pd catalyst with superior electrocatalytic activity towards ethanol electro-oxidation. Int J Hydrogen Energy 37 2579-2587... [Pg.154]

Liu J, Zhou H, Wang Q, Zeng F, Kuang Y (2012) Reduced graphene oxide supported palladium silver bimetallic nanoparticles for ethanol electro-oxidation in alkaline media. J Mater Sci 47 2188-2194... [Pg.154]

Wei YC, Liu CW, Kang WD, Lai CM, Tsai LD, Wang KW (2011) Electro-catalytic activity enhancement of Pd-Ni electrocatalysts for the ethanol electro-oxidation in alkaline medium the promotional effect of Ce02 addition. J Electroanal Chem 660 64—70... [Pg.155]

Nguyen ST, Law HM, Nguyen HT, Kristian N, Wang S, Chan SH, Wang X (2009) Enhancement effect of Ag for Pd/C towards the ethanol electro-oxidation in alkaline media. Appl Catal B Environ 91 507-515... [Pg.155]

Shen SY, Zhao TS, Xu JB, Li YS (2011) High performance of a cartxm supported ternary PdIrNi catalyst fOT ethanol electro-oxidation in anion exchange membrane direct ethanol fuel cells. Energy EnvitOTi Sci 4 1428-1433... [Pg.155]

Jiang L, Hsu A, Chu D, Chen R (2010) Ethanol electro-oxidation on Pt/C and PtSn/C catalysts in alkaline and acid solutions. Int J Hydrogen Energy 35(1) 365—372... [Pg.476]

Camara GA, de Lima RB, Iwasita T (2004) Catalysis of ethanol electro oxidation by PtRu the influence of catalyst composition. Electrochem Commun 6 812-815... [Pg.409]

Rao V, Hariyanto H, Cremers C, Stimming U (2007) Investigation of the ethanol electro-oxidation in alkaline membrane electrode assembly by differential electrochemical mass spectrometry. Fuel Cells 7 417... [Pg.888]

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