| Summary: | 碩士 === 國立成功大學 === 化學工程研究所 === 82 === The purposes of this thesis are intenteded to investigate the
effects of various Ni-Mo codeposits (prepared by
electroplating) on the performance of hydrogen evolution
reaction (HER),corrosion inhibition and benzyl alcohol
oxidation. The physical and electrochemical properties of Ni-Mo
deposits are majorly influenced by electroplating solution pHs
and species used for adjusting electroplating solution pH.
Gradual change in preferred orientation for Ni-Mo crystalline
growth from Ni<111> to Ni<200>, gradual increase in NiO and
MoO3 within the Ni-Mo deposits, and gradual increase in rate
for HER were simultaneous- ly found when pH values of
electroplating solutions increased. The passive currents of Ni-
Mo codeposits increase with increa sing Mo content within the
codeposits in 1N HCl,1N H2SO4 and 0.1N NaCl . In 1N HNO3, no
passive but direct pitting phenomenon was observed. The
electrochemically active surface area (EASA for Ni(OH)2 / NiOOH
transition) and limiting current for benzyl alcohol oxidat- ion
on Ni-Mo codeposits are much larger than those on a pure Ni in
basic solutions. Increase in EASA and limiting current for be-
nzyl alcohol oxidation and decrease in oxygen evolution rate
were observed as Mo content in codeposits increased. High
initialy concentration of benzyl alcohol, high temperat- ure of
electrolyte solution, low current density, and no addition of
tert-butanol result in a high selectivity and current efficie-
ncy for benzyl aldehyde production and benzyl alcohol
oxidation, respectively. In 0.5N KOH with 0.6M benzyl alcohol
at 60℃, 81.85 % selectivity for benzyl aldehyde and
approximately 100% current efficiency for benzyl alcohol
oxidation were obtained under 5 mA/cm2.
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