Enhanced Capability of Photoelectrochemical CO2 Conversion System Using an AlGaN/GaN Photoelectrode
We report significantly improved photosynthesis system based on AlGaN/GaN photochemical process. The resultant energy conversion efficiency is 0.13% which is the same level as that of real plants. The capability of this system is enhanced by high cathode potential due to the reduction of energy loss...
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| Published in | Jpn J Appl Phys Vol. 52; no. 8; pp. 08JF07 - 08JF07-5 |
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| Main Authors | , , , , |
| Format | Journal Article |
| Language | English |
| Published |
The Japan Society of Applied Physics
01.08.2013
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| Online Access | Get full text |
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| Summary: | We report significantly improved photosynthesis system based on AlGaN/GaN photochemical process. The resultant energy conversion efficiency is 0.13% which is the same level as that of real plants. The capability of this system is enhanced by high cathode potential due to the reduction of energy loss while utilizing the piezoelectric effect in the AlGaN/GaN heterostructure. The Faradaic efficiency of the CO 2 conversion to organic materials is enhanced, accompanied by an increment in photocurrent by modification of the AlGaN/GaN photoelectrode structure and electrolytes. Furthermore, reaction products such as C 2 H 4 and C 2 H 5 OH are generated by light illumination alone. |
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| Bibliography: | (Color) (a) Schematic illustration of photoelectrochemical CO 2 conversion system and (b) schematic equivalent circuit of the CO 2 conversion system. Series resistance with the photoelectrode ($R_{\text{s}}$) and total solution resistance with the electrolytes ($R_{\text{sol}}$) exist in the reaction circuit. Experimental photo $I$--$V$ data of the CO 2 conversion system measured using potentiostat (open circles) and fitted curves (solid line). Parameters extracted by the fitting are as follows: $I_{\text{p}} = 23.4$ mA, $I_{0} = 1.0$ μA, $n= 4.65$, $R = 42$ $\Omega$, and $R_{\text{sh}} = 1$ k$\Omega$. Schematic structures of the photoelectrodes used in our photoelectrochemical CO 2 conversion system. (a) uid-AlGaN/n + -GaN layer on sapphire (sapphire-PE) and (b) uid-AlGaN/n + -GaN layer on GaN substrate (GaN-PE). Time course of photocurrent measured in systems A, B, and C during the reaction. HCOOH production rates from different systems A, B, C normalized by the result for system A. The HCOOH production rate increases with lower the system resistance. (Color) Comparison of Faradaic efficiencies for each reaction products generated by CO 2 reduction in (a) system C using 1.0 M KHCO 3 and (b) system D using 3.0 M KCl. In system D, the ratio of CO was markedly increased, with C 2 H 4 and C 2 H 5 OH also being produced. |
| ISSN: | 0021-4922 1347-4065 |
| DOI: | 10.7567/JJAP.52.08JF07 |