(A) Photoelectrochemistry. The SECCM applied potential, E, is swept, as the illumination, P, of
the substrate is switched on and off, resulting in the measured local
current, i (traces, left). Photocurrent image of
individual MoS2 particle obtained via SECCM (top right),
and averaged dark currents (solid lines) and photocurrents (dashed
lines) observed at points across the basal plane (red) and edge plane
(green). Reproduced from Strange, L. E.; Yadav, J.; Garg, S.; Shinde,
P. S.; Hill, J. W.; Hill, C. M.; Kung, P.; Pan, S. J. Phys.
Chem. Lett.2020, 11 (9), 3488–3494
(ref (281)). Copyright
2020 American Chemical Society. (B) Electrocatalysis at layered Co(OH)2 plates. The oxygen evolution reaction (OER) current density
as a function of position in scanning constant height mode for the
particles shown on the right; the OER current density map obtained
from hopping-mode SECCM movie at a series of voltage. Reprinted by
permission from Macmillan Publishers Ltd.: Nature, Mefford, J. T.;
Akbashev, A. R.; Kang, M.; Bentley, C. L.; Gent, W. E.; Deng, H. D.;
Alsem, D. H.; Yu, Y. S.; Salmon, N. J.; Shapiro, D. A.; et al. Nature2021, 593 (7857), 67–73
(ref (206)). Copyright
2021. (C) Top left: EBSD map of polycrystalline gold, with inverse
pole figure legend of surface orientation. The white rectangle indicates
the location of SECCM measurements in CO2 atmosphere. Bottom
left: Representative linear sweep voltammogram extracted from grains
and grain boundary. Right: Equipotential snapshot at −1.05
V vs Ag/AgCl obtained from SECCM movie, displaying spatially resolved
eCO2RR activity. The lattice rotation gradient ∂ω23/∂x and derived geometrically necessary dislocation
(GND) map of grain boundary. Reprinted by permission from Macmillan
Publishers Ltd.: Nature Materials, Mariano, R. G.; Kang, M.; Wahab,
O. J.; McPherson, I. J.; Rabinowitz, J. A.; Unwin, P. R.; Kanan, M.
W., Nat. Mater.2021, 20 (7), 1000–1006 (ref (237)). Copyright 2021. (D) Grain-resolved eCO2RR
current density at −1.05 V vs Ag/AgCl plotted vs the corresponding
average grain orientation relative to low-index orientation poles
at polycrystalline Cu. Reproduced from Wahab, O. J.; Kang, M.; Daviddi,
E.; Walker, M.; Unwin, P. R. ACS Catal.2022, 12 (11), 6578–6588 (ref (236)) under CC BY 4.0 license.