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Phenomena Overpotensial

Hydrogen

Phenomena Overpotensial

Hydrogen

Syahrul Ullum

3334 081639

T. Metalurgi5 April 20111

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Outline

1 Pendahuluan

2 Termodinamika Overpotensial Hidrogen

3 Kinetika Overpotensial Hidrogen

4Referensi

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PENDAHULUAN

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OVERPOTENSIAL?

Selisih potensial proses dengan potensial

kesetimbanganL = Eapplied Eequilibrium

Jenis-Jenis Overpotensial1. Overpotensial Konsentrasi

2. Overpotensial Aktivasi

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Termodinamika Overpotensial

Diagram PolariasiDiagram Polariasi

3 Kondisi

Tidak PerluTidak Perlu

OverpotensialOverpotensial

Aqueous Solution

PerluPerlu

OverpotensialOverpotensial

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PerluPerluOverpotensialOverpotensial

Aqueous Solution Non Aqueous Solution

Deret

Volta

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Kondisi I

(a)

Noble

Metals

0E

+

M / M2+

H2 / H+

i

_

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Penjelasan

AAUntuk logam Mulia (Cu,Ag,Au)

BBBersifat kurang reaktif

CC

Aqueous solution electrolysis

DDEfisiensi arus tinggi (hampir 100%)

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Kondisi II

(b)

Metals with

Intermediate

Reactivity

0

E

+

M / M2+

H2 / H+

i

_

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Penjelasan

AAIntermediate reaktivity

BBUntuk Ni, Zn, Cd dan Fe

CC

Aqueous solution electrolysis

DDOverpotensial H2 lebih tinggi

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Kondisi III

(c)

Reactive

Metals

0E

+

M / M2+

H2 / H+

i

_

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Penjelasan

AALogam yang sangat reaktif

BBLogam Alkali dan alkali tanah

CC

Non Aqueous solution ex. Fused salt

DDOverpotensial H2 sangat tinggi

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Kinetika Overpotensial Hidrogen

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Penjelasan

I. Difusi H3O+ dari Bulk Solution menuju double layer

II. H3O+ melewati Double Layer

III. PenguraianH3O

+ = H2O + e

IV. Electrochemical

H3O+ + M + e- p M-H + H2O

2 M-H p 2M + H2

V. Desorpsi gas H2 dari NBL

VI. Pengeluaran gas H2 dari Bulk Solution

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ReferensiH.S Ray & A. Gosh. 1991 Principles of Extractive

Metallurgy 2nd ed.New Delhi : John Willey & Son

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5 April 201115