• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.227.2-227.2
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• 2010

본 연구에서는 양극산화된 $TiO_2$ 전극(anodized tubular $TiO_2$ electrode, ATTE)을 수소제조용 PEC(Photoelectrochemical)시스템에서 광어노드와 기존의 백금전극을 대체하고 $H^+$ 환원능을 향상시키기 위하여 엔자임(Pyrococcus furiosus, Pfu)을 고정화한 후 캐소드로 동시에 활용하였으며, 엔자임 고정을 위한 crosslinker 종류 및 금속담지 여부, ATTE 길이를 통한 수소발생양에 미치는 영향을 연구하였다. ATTE 표면과 엔자임의 amine group의 연결을 위하여 heterobifunctional crosslinker로써 사슬 길이가 상대적으로 짧은 Sulfo-SDA가 유리하였으며, 금속담지의 경우 짧은 튜브의 경우 1% 내에서 효과가 증진되었으나 긴 튜브의 경우는 오히려 광전류 및 궁극적으로 수소발생속도에 불리하게 작용하였다. 또한, 튜브 길이가 긴 ATTE가 짧은 ATTE 보다 수소발생양에서 더욱 효율적임을 알 수 있었다. 텅스텐산화물 담지의 가시광감응에의 담지 효과는 예비 실험 결과로 나타나지 않아, 추가적인 연구가 필요한 것으로 판단된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.749-752
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• 2009

Anodized tubular titania ($TiO_2$) electrodes (ATTEs) are prepared and used as both the photoanode and the cathode substrate in a photoelectrochemical system designed to split water into hydrogen with the assistance of an enzyme and an external bias (solar cell). In particular, the ATTE used as the cathode substrate for the immobilization of the enzyme is prepared by two methods; adsorption and crosslinking. Results show that the optimized amount of enzyme is 10.98 units for the slurried enzyme, 3.66 units for the adsorbed one and 7.32 units for the crosslinked one, and the corresponding hydrogen evolution rates are 33.04, 148.58, and 234.88 umol/hr, respectively. The immobilized enzyme, specifically the chemically crosslinked one, seems to be much superior to the slurried enzyme, due to the enhanced charge-transfer process that is caused by the lower electrical resistance between the enzyme and the ATTE. This results in a greater number of accepted electrons and a larger amount of enzymes able to deal with the electrons.

• 한국수소및신에너지학회논문집
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• 제22권5호
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• pp.656-662
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• 2011

The purpose of this study was to correlate between photoelectrochemcial hydrogen production rate and electron transfer with various types of metal doped $TiO_2$ nanotubes as photoanodes. In order to fabricate light sensitized photoanode, CdS, $WO_3$, and Pt were doped by electrodeposition method. As the results of experiments, the electron transfer was favorable from higher position to lower position of conduction band (CB). In consequence, the higher hydrogen production rate was as follows, CdS/$TiO_2$ (100 $umol/hr-cm^2$) > $WO_3/TiO_2$ (20 $umol/hr-cm^2$) > Pt/$TiO_2$ (10 $umol/hr-cm^2$). The surface characterizations exhibited that crystal structure, morphological and electrical properties of various metal depoed $TiO_2$ nanotubes by the results of SEM, TEM, XPS, and photocurrent measurements.

• 한국수소및신에너지학회논문집
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• 제18권3호
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• pp.244-249
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• 2007

The present work considers the concept of enzymatic photoelectrochemical generation of hydrogen through water splitting using a Xe lamp as a source of light. A solar cell was applied to the system in order to shift the level of electrochemical energy of the system, resulting in the rate of hydrogen production at $43\;{\mu}mol/(cm^2{\times}hr)$ in cathodic compartment with an anodized tubular $TiO_2$ electrode(ATTE, $5^{\circ}C$/1hr in 0.5 wt% HF-$650^{\circ}C$/5hr). The trend of the rate of hydrogen production, for the ATTEs with different annealing temperature from $350^{\circ}C$ to $850^{\circ}C$, fairly well coincided with the photoelectrical properties measured by potentiostat. The actual chemical bias through imposition of two electrolytes of different pHs between anode(13.68) and cathode(7.5) was 0.24eV.

• 한국수소및신에너지학회논문집
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• 제22권4호
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• pp.432-442
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• 2011

Anodized tubular $TiO_2$ electrodes (ATTEs) with three noticeably different lengths are prepared to determine their optimum length for the photo-driven activity in the reaction of Cr(VI) reduction and hydrogen evolution. The ATTEs with ethylene glycol have longer $TiO_2$ tubes (7-15.6 ${\mu}m$) than those with hydrfluoric acid (0.6-0.8 ${\mu}m$). These samples, which differ only in the length of the tubes, with a wall thickness of ca. 20 nm, consist mainly of an anatase crystalline phase after heat treatment at $650^{\circ}C$, since the anatase crystallites at the tube walls do not undergo transformation into rutile phase, due to the constraints imposed by the wall thickness. Among them, the medium size (ca. 8 ${\mu}m$) tubes provide the optimum conditions, irrespective of the light intensity, which is explained in terms of the correlation between the amount of photons and the adsorbed electron acceptors and their location. Photocatalytic Cr(VI) reduction leads to ca. 60% reduction of Cr(VI) even under 1 sun irradiation with the medium-sized anodized $TiO_2$ tubes, but only ca. 20% with the short- and long-sized tubes. For hydrogen evolution, tubes longer than 8 ${\mu}m$ do not exhibit better performance with any light intensity.