The electrochemistry of metal nanoparticles for oxygen reduction and nitrate/nitrite reduction

Siriwatcharapiboon, Wilai (2013). The electrochemistry of metal nanoparticles for oxygen reduction and nitrate/nitrite reduction. University of Birmingham. Ph.D.

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Abstract

This research has scientific aims focused on two important electrochemical reactions: oxygen reduction and nitrate/nitrite reduction. A series of rhodium (Rh) deposited on gold nanorods (Au NRs) and gold nanoparticles (Au NPs) were synthesised by wet chemical reduction. The scanning transmission electron microscopy (STEM) showed that Rh has a preferential deposition and epitaxial growth at the end of Au NRs. Cyclic voltammetry and rotating disc electrode (RDE) measurements were performed to study the oxygen reduction at these Au:Rh/C catalysts.

Pyrolysed cobalt triethylenetetraamine on a carbon substrate (Co/TET A/C) was employed to produce H20 2 from the ORR. The results from the rotating ring disc electrode (RRDE) reveal that the heat treatment influences the H20 2 selectivity. The Co/TETA/C heated at 1000 oc yields the highest
H20 2 selectivity while the Co/TETA/C heated at 700 oc yields the lowest H20 2 selectivity.

Rh/C, Au:Rh/C nanoparticles and Sn modified Rh/C nanoparticles were employed for nitrate/nitrite reduction in acidic media. Results from on-line electrochemical mass spectrometry
(OLEMS) reveal that the modified electrode generates N2 from further reduction of the nitrous oxide (N20) intermediate. Ion chromatography (IC) shows that ammonium is the main product at Rh/C.
Hydroxylamine can also be detected after Sn modification on Rh/C.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):