Promotion of the electrocatalytic reduction of nitrate

Leiden Repository

Promotion of the electrocatalytic reduction of nitrate

Title: Promotion of the electrocatalytic reduction of nitrate
Author: Yang, Jian
Publisher: Leiden Institute of Chemistry (LIC), Faculty of Science, Leiden University
Issue Date: 2013-10-24
Keywords: Electrocatalysis
Platinum
Nitrate Reduction
Tin
p-block Metal
On-line Electrochemical Mass Spectrometry
Ion Chromatography
Rhodium
pH
Electrochemistry
Abstract: Nitrate reduction on Sn-modified polycrystalline Pt has been investigated. NO is the main product at high Sn coverage, whereas N2O is dominant at low Sn coverage. The N2O reduction on Sn-modified Pt electrodes indicates electrochemical formation of N2 is related to pristine Pt sites. Moreover, homogeneous chemical reactions of intermediates products also contribute to N2O and N2 formation of in solution. The p-block metals have been studied: Cd, In and Sn show a promoting effect; Ga shows a limited enhancement; Tl shows a special promoting effect in sulfuric acid; Pb shows a weak formation of N2O. Density Functional Theory calculations show that Sn and In enhance nitrate adsorption compared with pristine Pt. Moreover, ammonia is found as the only product on Pt. After modification by Sn, hydroxylamine is specifically found with nitrite, which supports that nitrate reduction to nitrite is enhanced by Sn and Sn could steer the hydrogenation of NOads. However, solution pH is an important factor. On Pt, nitrate reduction is only observed in acidic solution. On Rh, a higher activity is observed in wide pH, which suggests a mechanism that HNO3 molecule is the active species. However, Rh additionally shows a special ability to reduce NO3- directly.
Description: Promotor: M.T.M. Koper
With summary in Dutch
Faculty: Faculteit der Wiskunde en Natuurwetenschappen
Citation: Yang, J., 2013, Doctoral thesis, Leiden University
ISBN: 9789461823588
Handle: http://hdl.handle.net/1887/22045
 

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