Abstract
We report the use of polyterthiophenes (PTTh) as a rare, combined light-harvester and catalyst for the hydrogen evolution reaction at high pH. Illuminated PTTh in combination with a MnOx anode in a two-electrode setup exhibited stable water-splitting at a bias-potential of only 0.3 V at pH 12. This confirms that PTTh used as photocathode can produce photovoltages of at least 900 mV for the hydrogen evolution reaction at high pH and is therefore a suitable match for traditional water-oxidation catalysts such as MnOx, CoOx, and RuOx. Films of PTTh were fabricated using a novel, metal-free method where iodine vapor is used as oxidant; thus, previously observed interference from metal residuals was omitted and thereby a gravimetric photo electrocatalytic conversion rate of 330 mmol(H2) h-1 g-1 was achieved in phosphate buffer (pH 7) at 0 V vs. RHE. A striking property of this new strand of polythiophene was an "inverse" correlation (compared to that predicted using the Nernstian relationship) between the onset potential for the light-assisted water reduction reaction and pH: the potential (vs. RHE) required for a given current was more positive at higher pH, which is not observed for other (photo-) electrocatalytic materials, and indicates that the charge neutralization of PTTh (rather than the pH) guides the onset potential.
| Original language | English |
|---|---|
| Pages (from-to) | 1335-1342 |
| Number of pages | 8 |
| Journal | Energy and Environmental Science |
| Volume | 11 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 2018 May 1 |
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ASJC Scopus subject areas
- Environmental Chemistry
- Renewable Energy, Sustainability and the Environment
- Nuclear Energy and Engineering
- Pollution
Cite this
Light-assisted electrochemical water-splitting at very low bias voltage using metal-free polythiophene as photocathode at high pH in a full-cell setup. / Oka, Kouki; Tsujimura, Orie; Suga, Takeo; Nishide, Hiroyuki; Winther Jensen, Bjorn.
In: Energy and Environmental Science, Vol. 11, No. 5, 01.05.2018, p. 1335-1342.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Light-assisted electrochemical water-splitting at very low bias voltage using metal-free polythiophene as photocathode at high pH in a full-cell setup
AU - Oka, Kouki
AU - Tsujimura, Orie
AU - Suga, Takeo
AU - Nishide, Hiroyuki
AU - Winther Jensen, Bjorn
PY - 2018/5/1
Y1 - 2018/5/1
N2 - We report the use of polyterthiophenes (PTTh) as a rare, combined light-harvester and catalyst for the hydrogen evolution reaction at high pH. Illuminated PTTh in combination with a MnOx anode in a two-electrode setup exhibited stable water-splitting at a bias-potential of only 0.3 V at pH 12. This confirms that PTTh used as photocathode can produce photovoltages of at least 900 mV for the hydrogen evolution reaction at high pH and is therefore a suitable match for traditional water-oxidation catalysts such as MnOx, CoOx, and RuOx. Films of PTTh were fabricated using a novel, metal-free method where iodine vapor is used as oxidant; thus, previously observed interference from metal residuals was omitted and thereby a gravimetric photo electrocatalytic conversion rate of 330 mmol(H2) h-1 g-1 was achieved in phosphate buffer (pH 7) at 0 V vs. RHE. A striking property of this new strand of polythiophene was an "inverse" correlation (compared to that predicted using the Nernstian relationship) between the onset potential for the light-assisted water reduction reaction and pH: the potential (vs. RHE) required for a given current was more positive at higher pH, which is not observed for other (photo-) electrocatalytic materials, and indicates that the charge neutralization of PTTh (rather than the pH) guides the onset potential.
AB - We report the use of polyterthiophenes (PTTh) as a rare, combined light-harvester and catalyst for the hydrogen evolution reaction at high pH. Illuminated PTTh in combination with a MnOx anode in a two-electrode setup exhibited stable water-splitting at a bias-potential of only 0.3 V at pH 12. This confirms that PTTh used as photocathode can produce photovoltages of at least 900 mV for the hydrogen evolution reaction at high pH and is therefore a suitable match for traditional water-oxidation catalysts such as MnOx, CoOx, and RuOx. Films of PTTh were fabricated using a novel, metal-free method where iodine vapor is used as oxidant; thus, previously observed interference from metal residuals was omitted and thereby a gravimetric photo electrocatalytic conversion rate of 330 mmol(H2) h-1 g-1 was achieved in phosphate buffer (pH 7) at 0 V vs. RHE. A striking property of this new strand of polythiophene was an "inverse" correlation (compared to that predicted using the Nernstian relationship) between the onset potential for the light-assisted water reduction reaction and pH: the potential (vs. RHE) required for a given current was more positive at higher pH, which is not observed for other (photo-) electrocatalytic materials, and indicates that the charge neutralization of PTTh (rather than the pH) guides the onset potential.
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U2 - 10.1039/c7ee03669h
DO - 10.1039/c7ee03669h
M3 - Article
VL - 11
SP - 1335
EP - 1342
JO - Energy and Environmental Science
JF - Energy and Environmental Science
SN - 1754-5692
IS - 5
ER -