Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Pyramid-like deposits

The electrode surface roughness at low level of coarseness can be increased in some different ways other than dendrites (spongy-like deposit,33 honeycomb-like structure,76,77 pyramid-like deposit,83 etc.) on the microscale. The properties of electrodeposits on nanoscale should be also taken into consideration.84,85 Further investigation will show which one of them is the best for this purpose. This chapter is written in order to initiate it. [Pg.209]

Fig. 5.8 (a, b) The pyramid-like and (c, d) dendritic structures of Cu obtained by the pulsating overpotential (PO) regimes with the same pause-to-pulse ratio 10, but with the different durations of deposition pulse (4) and pause (tp) (a, b) t = ms and tp = 10 ms, (c, d) = 10 ms and tp= 100 ms (Reprinted from Refs. [49, 50] with permission from Elsevier and Refs. [5, 23, 51] with kind permission from Springer)... [Pg.188]

The pyramid-like forms were electrodeposited by square-wave PO with a deposition pulse of 1 ms (Fig. 4.15a, b). These pyramid-like forms represent precursors of dendrites, what is concluded by the comparison with the top of copper dendrites obtained by copper electrodeposition at a constant overpotential of 650 mV (Fig. 4.15c). Copper pyramids of different shapes are also obtained by electrodeposition in a constant regime of electrolysis, where the morphology of pyramidal nanoparticles depended on the ratio of the concentration of surfactant/precursor and deposition time [42], Despite the fact that the overpotential amplitude of 1,000 mV was used, holes for which the origin was of attached hydrogen bubbles were not formed (Fig. 4.15a). The absence of holes clearly indicates that a deposition pulse of 1 ms was insufficient for the formation of hydrogen bubbles. [Pg.207]

Fig. 4.15 (a) and (b) Pyramid-like precursors of dendrites obtained by square-wave PO with a deposition pulse of 1 ms and a pause of 10 ms deposition time 1,800 s, (c) top view of copper dendrite obtained by electrodeposition at an overpotential of 650 mV (Reprinted from [41] with permission from Elsevier.)... [Pg.208]

Nanopyramidal, nanorod-like, and spherical gold nanostructures were also used to study the ORR in 0.5 M KOH [85]. They were synthesized on polyciystalline gold substrates through electrochemical overpotential deposition by manipulating the deposited potentials and concentrations of HAuCLj. X-ray diffractimi and electrochemical experiments showed that the pyramidal structures were dominated by 111 facets, and therefore due to the lowest amount of 100 sites, the activity toward ORR was the lowest. The reduction peak current increased and the peak potential shifted positively in the following order nanopyramids < nanorods < nanospheres. [Pg.502]

If rough surfaces are to be measured, then a tip shaped like a needle will have fewer problems than a pyramid or cone, even if the cone has a very small radius at the tip. Tips of this form are made by etching away material from a standard tip, or adding a thin spire to it by electron beam assisted chemical vapor deposition (CVD), and are available commercially. These can probe deep and narrow trenches, but they are more easily... [Pg.348]


See other pages where Pyramid-like deposits is mentioned: [Pg.223]    [Pg.188]    [Pg.2]    [Pg.436]    [Pg.1246]    [Pg.5]    [Pg.191]    [Pg.636]    [Pg.96]    [Pg.12]    [Pg.40]    [Pg.323]    [Pg.5]    [Pg.210]    [Pg.1246]    [Pg.119]    [Pg.119]    [Pg.450]    [Pg.654]    [Pg.6]    [Pg.654]    [Pg.139]    [Pg.80]   
See also in sourсe #XX -- [ Pg.209 ]




SEARCH



© 2024 chempedia.info