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Nitrate reduction at Pt(1 0 0) single crystals and preferentially oriented nanoparticles in neutral media

Paper ID Volume ID Publish Year Pages File Format Full-Text
54990 47036 2013 10 PDF Available
Title
Nitrate reduction at Pt(1 0 0) single crystals and preferentially oriented nanoparticles in neutral media
Abstract

The electroreduction of nitrate on Pt(1 0 0) electrodes in phosphate buffer neutral solution, pH 7.2, is reported. The sensitivity of the reaction to the crystallographic order of the surface is studied through the controlled introduction of defects by using stepped surfaces with (1 0 0) terraces of different length separated by monoatomic steps, either with (1 1 1) or (1 1 0) symmetry. The results of this study show that nitrate reduction occurs mainly on the well defined (1 0 0) terraces in the potential region where H adsorption starts to decrease, allowing the nitrate anion to access the surface. Adsorbed NO has been detected as a stable intermediate in this media. An oxidation process observed at 0.8 V has been identified as leading to the formation of adsorbed NO and being responsible for a secondary reduction process observed in the subsequent negative scan. Using in situ FTIRS, ammonium was found to be the main product of nitrate reduction. This species can be oxidized at high potentials resulting in adsorbed NO and nitrate (probably with nitrite as intermediate).

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (167 K)Download as PowerPoint slideHighlights► Nitrate reduction in Pt(1 0 0) on neutral media was studied. ► The reaction occurs on the {1 0 0} well-defined terraces. ► When steps are introduced, the catalytic activity decreases. ► FTIR shows that ammonia is the main product of nitrate reduction at neutral pH. ► Cubic nanoparticles show similar behaviour to medium-terrace (1 0 0) vicinal surfaces.

Keywords
Platinum surfaces; Single crystals; Nitrate reduction; FTIRS; NO stripping; Neutral media; Phosphate buffer
First Page Preview
Nitrate reduction at Pt(1 0 0) single crystals and preferentially oriented nanoparticles in neutral media
Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 202, 15 March 2013, Pages 2–11
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis