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A Mechanism of Adsorption of β‐Nicotinamide Adenine Dinucleotide on Graphene Sheets: Experiment and Theory
Author(s) -
Pumera Martin,
Scipioni Roberto,
Iwai Hideo,
Ohno Takahisa,
Miyahara Yuji,
Boero Mauro
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200900399
Subject(s) - graphene , passivation , x ray photoelectron spectroscopy , nicotinamide adenine dinucleotide , nad+ kinase , adsorption , electrochemistry , chemistry , inorganic chemistry , electrode , molecule , materials science , chemical engineering , nanotechnology , organic chemistry , enzyme , layer (electronics) , engineering
β‐Nicotinamide adenine dinucleotide (NAD + ) and its reduced form (NADH) play major roles in the development of electrochemical enzyme biosensors and biofuel cells. Unfortunately, the oxidation of NADH at carbon electrodes suffers from passivation of the electrodes and a decrease in passing currents. Here, we investigate experimentally and theoretically the reasons for such passivation. High‐resolution X‐ray photoelectron spectroscopy (HR‐XPS), voltammetry, and amperometry show that adsorption occurs on the edges and “edge‐like” defects of graphene sheets. HR‐XPS and ab initio molecular dynamics show that the adsorption of NAD + molecules on the edges of graphene happens due to interaction with oxygen‐containing groups such as carboxylic groups, while graphene edges substituted only with hydrogen are prone to passivation.