eprintid: 10088137
rev_number: 14
eprint_status: archive
userid: 608
dir: disk0/10/08/81/37
datestamp: 2019-12-19 11:07:24
lastmod: 2020-02-13 07:37:54
status_changed: 2019-12-19 11:07:24
type: article
metadata_visibility: show
creators_name: Bamgbelu, L
creators_name: Holt, KB
title: In Situ Determination of pH at Nanostructured Carbon Electrodes Using IR Spectroscopy
ispublished: pub
divisions: UCL
divisions: A01
divisions: B04
divisions: C06
divisions: F56
keywords: IR spectroscopy, carbon nanotubes, electrode, interface, pH, phosphate, spectroelectrochemistry
note: This work is licensed under a Creative Commons Attribution 4.0 International License. The images
or other third party material in this article are included in the Creative Commons license,
unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license,
users will need to obtain permission from the license holder to reproduce the material. To view a copy of this
license, visit http://creativecommons.org/licenses/by/4.0/
abstract: Changes in pH at electrode surfaces can occur when redox reactions involving the production or consumption of protons take place. Many redox reactions of biological or analytical importance are proton-coupled, resulting in localized interfacial pH changes as the reaction proceeds. Other important electrochemical reactions, such as hydrogen and oxygen evolution reactions, can likewise result in pH changes near the electrode. However, it is very difficult to measure pH changes located within around 100 µm of the electrode surface. This paper describes the use of in situ attenuated total reflectance (ATR) infrared (IR) spectroscopy to determine the pH of different solutions directly at the electrode interface, while a potential is applied. Changes in the distinctive IR bands of solution phosphate species are used as an indicator of pH change, given that the protonation state of the phosphate ions is pH-dependent. We found that the pH at the surface of an electrode modified with carbon nanotubes can increase from 4.5 to 11 during the hydrogen evolution reaction, even in buffered solutions. The local pH change accompanying the hydroquinone-quinone redox reaction is also determined.
date: 2019-12-05
date_type: published
official_url: https://doi.org/10.3390/ma12244044
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 1731324
doi: 10.3390/ma12244044
pii: ma12244044
lyricists_name: Holt, Katherine
lyricists_id: KHOLT76
actors_name: Kalinowski, Damian
actors_id: DKALI47
actors_role: owner
full_text_status: public
publication: Materials
volume: 12
number: 24
article_number: 4044
event_location: Switzerland
citation:        Bamgbelu, L;    Holt, KB;      (2019)    In Situ Determination of pH at Nanostructured Carbon Electrodes Using IR Spectroscopy.                   Materials , 12  (24)    , Article 4044.  10.3390/ma12244044 <https://doi.org/10.3390/ma12244044>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10088137/1/Holt_In%20Situ%20Determination%20of%20pH%20at%20Nanostructured%20Carbon%20Electrodes%20Using%20IR%20Spectroscopy_VoR.pdf