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Establishing a Link between Well-Ordered Pt(100) Surfaces and Real Systems: How Do Random Superficial Defects Influence the Electro-oxidation of Glycerol?
journal contribution
posted on 2015-07-02, 00:00 authored by Pablo S. Fernández, Janaina Fernandes Gomes, Camilo A. Angelucci, Polina Tereshchuk, Cauê A. Martins, Giuseppe A. Camara, Marı́a
E. Martins, Juarez L. F. Da Silva, Germano Tremiliosi-FilhoGlycerol (GlOH) accumulation and
its very low price constitute
a real problem for the biodiesel industry. To overcome these problems,
it is imperative to find new GlOH applications. In this context, electrochemistry
arises as an important alternative to the production of energy or
fine chemicals using GlOH as a reactant. To make these opportunities
a reality, it is fundamentally necessary to understand how the glycerol
electro-oxidation reaction (GEOR) occurs on catalysts used in real
systems. Thus, research using model surfaces has generated the first
insight into the electrochemistry of extremely complex real catalysts.
Accordingly, in this work, we generate Pt(100) disturbed surfaces
in a reproducible manner, carefully controlling the surface defect
density. Then, GEOR is studied on well-ordered Pt(100) and on the
disturbed Pt(100) surfaces in 0.5 M H2SO4 using
cyclic voltammetry (CV) and in situ Fourier transform infrared spectroscopy
(FTIR). The CV profile of GEOR consists of a single peak in the positive
scan. The onset reaction displays the influence of defects present
on the surface. On a surface with a high degree of disorder, the main
GlOH oxidation process begins at 0.8 V vs RHE, whereas for well-ordered
Pt(100), it starts 0.1 V earlier. FTIR experiments show the presence
of carbon monoxide and carbonyl absorption bands. The electrochemical
and spectroelectrochemical results are supported by density functional
theory calculations showing that both CO and GlOH bind more strongly
on disturbed than on well-ordered surfaces. Thus, our experiments
show that Pt–CO (or other GlOH residue) bond breaking may be
the GEOR rate-determining step.
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spectroelectrochemical resultsReal Systems0.1 VFTIR experiments showcarbon monoxideonset reaction displaysPtGlOH oxidation processtheory calculationscarbonyl absorption bandscyclic voltammetryCV profilemodel surfacesGlOH residueCO0.5 M H 2SObiodiesel industryGlOH applicationsRandom Superficial Defects InfluenceGEORexperiments showsurface defect densityGlOH bind0.8 V vs RHE
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