UCL logo

UCL Discovery

UCL home » Library Services » Electronic resources » UCL Discovery

Formation and electrocatalysis studies of nickel and iron sulfide catalysts using in situ XAS

Islam, H-U; (2016) Formation and electrocatalysis studies of nickel and iron sulfide catalysts using in situ XAS. Doctoral thesis , UCL (University College London). Green open access

[img]
Preview
Text
Islam_thesis-160901-HUI.pdf

Download (5MB) | Preview

Abstract

X-ray absorption spectroscopy (XAS) is an atom specific characterisation technique. It is particularly useful for understanding dilute systems of short range order. When used in situ during reaction processes, the technique is a powerful tool to study the evolving local structure of materials. In this thesis, XAS is used to understand the synthesis, stability, and electrocatalytic activity of iron sulfides. A popular route to the synthesis of nanoparticulate sulfides is the solvothermal decomposition of transition metal dithiocarbamates. These single source precursors are typically dissolved in a coordinating solvent and heated rapidly. The coordinating solvent acts as a heat sink and capping agent but its role in each decomposition process is less understood. Here, it is shown through ex situ and in situ XAS that the coordinating solvent has significant effect on the starting material and decomposition process through coordination to the transition metal centre and reaction with the dithiocarbamate backbone. Case studies include the decomposition of zinc dimethyl, and nickel and iron diisobutyl dithiocarbamates in oleylamine. The solvothermal decomposition of iron or iron and nickel diisobutyl dithiocarbamate in the presence of thiuram disulfide results in the formation of Fe3S4 or NiFe2S4 nanoparticles. These inverse spinel structures are formed as hexagonal sheets with 001 and 111 surfaces which are predicted to be electrocatalytically active. The oxidation of the systems in electrolyte during cyclic voltammetry – a process that is thought to reduce catalytic activity – is investigated by in situ XAS.

Type: Thesis (Doctoral)
Title: Formation and electrocatalysis studies of nickel and iron sulfide catalysts using in situ XAS
Event: UCL (University College London)
Open access status: An open access version is available from UCL Discovery
Language: English
UCL classification: UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
URI: http://discovery.ucl.ac.uk/id/eprint/1508300
Downloads since deposit
237Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item