TY - JOUR
T1 - Nanoscale Reactivity Mapping of a Single-Crystal Boron-Doped Diamond Particle
AU - Ando, Tomohiro
AU - Asai, Kai
AU - Macpherson, Julie
AU - Einaga, Yasuaki
AU - Fukuma, Takeshi
AU - Takahashi, Yasufumi
N1 - Funding Information:
PRESTO (JPMJPR18T8) from the Japan Science and Technology Agency (JST), a Grant-in-Aid for Scientific Research (A) (19H00915), a Grant-in-Aid for Young Scientists (A) (15H05422), a Grant-in-Aid for Exploratory Research (15K13263 and 20K21141), and a Grant-in-Aid for Scientific Research on Innovative Areas (16H00885) from the Japan Society for the Promotion of Science (JSPS), World Premier International Research Center Initiative (WPI), MEXT, Japan, and Asahi Glass Foundation, a Grant-in-Aid for Young Scientists provided by Hokuriku bank, and Murata Science Foundation are all thankfully acknowledged for financial support.
Publisher Copyright:
©
PY - 2021/4/13
Y1 - 2021/4/13
N2 - Boron-doped diamond (BDD) is most often grown by chemical vapor deposition (CVD) in polycrystalline form, where the electrochemical response is averaged over the whole surface. Deconvoluting the impact of crystal orientation, surface termination, and boron-doped concentration on the electrochemical response is extremely challenging. To tackle this problem, we use CVD to grow isolated single-crystal microparticles of BDD with the crystal facets (100, square-shaped) and (111, triangle-shaped) exposed and combine with hopping mode scanning electrochemical cell microscopy (HM-SECCM) for electrochemical interrogation of the individual crystal faces (planar and nonplanar). Measurements are made on both hydrogen- (H-) and oxygen (O-)-terminated single-crystal facets with two different redox mediators, [Ru(NH3)6]3+/2+ and Fe(CN)64-/3-. Extraction of the half-wave potential from linear sweep and cyclic voltammetric experiments at all measurement (pixel) points shows unequivocally that electron transfer is faster at the H-terminated (111) surface than at the H-terminated (100) face, attributed to boron dopant differences. The most dramatic differences were seen for [Ru(NH3)6]3+/2+ when comparing the O-terminated (100) surface to the H-terminated (100) face. Removal of the H-surface conductivity layer and a potential-dependent density of states were thought to be responsible for the behavior observed. Finally, a bimodal distribution in the electrochemical activity on the as-grown H-terminated polycrystalline BDD electrode is attributed to the dominance of differently doped (100) and (111) facets in the material.
AB - Boron-doped diamond (BDD) is most often grown by chemical vapor deposition (CVD) in polycrystalline form, where the electrochemical response is averaged over the whole surface. Deconvoluting the impact of crystal orientation, surface termination, and boron-doped concentration on the electrochemical response is extremely challenging. To tackle this problem, we use CVD to grow isolated single-crystal microparticles of BDD with the crystal facets (100, square-shaped) and (111, triangle-shaped) exposed and combine with hopping mode scanning electrochemical cell microscopy (HM-SECCM) for electrochemical interrogation of the individual crystal faces (planar and nonplanar). Measurements are made on both hydrogen- (H-) and oxygen (O-)-terminated single-crystal facets with two different redox mediators, [Ru(NH3)6]3+/2+ and Fe(CN)64-/3-. Extraction of the half-wave potential from linear sweep and cyclic voltammetric experiments at all measurement (pixel) points shows unequivocally that electron transfer is faster at the H-terminated (111) surface than at the H-terminated (100) face, attributed to boron dopant differences. The most dramatic differences were seen for [Ru(NH3)6]3+/2+ when comparing the O-terminated (100) surface to the H-terminated (100) face. Removal of the H-surface conductivity layer and a potential-dependent density of states were thought to be responsible for the behavior observed. Finally, a bimodal distribution in the electrochemical activity on the as-grown H-terminated polycrystalline BDD electrode is attributed to the dominance of differently doped (100) and (111) facets in the material.
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U2 - 10.1021/acs.analchem.1c00053
DO - 10.1021/acs.analchem.1c00053
M3 - Article
AN - SCOPUS:85104917914
SN - 0003-2700
VL - 93
SP - 5831
EP - 5838
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 14
ER -