Amino-terminated diamond surfaces: Photoelectron emission and photocatalytic properties

SURFACE SCIENCE

卷:650

Article

Zhu, Di¹  Bandy, Jason A.¹  Li, Shuo¹  Hamers, Robert J.¹ 

[1] Univ Wisconsin, Dept Chem, 1101 Univ Ave, Madison, WI 53706 USA

关键词: Diamond;    Photocatalysis;    Amine;    Amino;    Electron emission;    Solvated electrons;   

DOI  :  10.1016/j.susc.2016.01.003

来源: Elsevier

【 摘 要 】

We report a new approach to making stable negative electron-affinity diamond surfaces by terminating diamond with amino groups (also known as amine groups, -NH2). Previous studies have shown that negative electron affinity can be induced by terminating diamond surfaces with hydrogen, creating a surface dipole favorable toward electron emission. Here, we demonstrate that covalent tethering of positive charges in the form of protonated amino groups, -NH3+, also leads to negative electron affinity (NEA) and facile electron emission into vacuum and into water. Amino-terminated diamond was prepared using a very mild plasma discharge. Valence-band photoemission studies of the amino-terminated diamond samples show a characteristic NEA peak, demonstrating that the amino-terminated surface has NEA. Diamond's ability to emit electrons into water was evaluated using photochemical conversion of N-2 to NH3. Time-resolved surface photovoltage studies were used to characterize charge separation at the diamond interface, and Mott-Schottky measurements were performed to characterize band-bending at the diamond-water interface. XPS studies show that the amino-terminated surfaces provide increased chemical resistance to oxidation compared with H-terminated diamond when illuminated with ultraviolet light. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

Free