【公開日：2024.07.25】【最終更新日：2024.06.24】
課題データ / Project Data
課題番号 / Project Issue Number
23HK0058
利用課題名 / Title
Fabricating NiO photocathode under strong coupling for photoreduction reaction
利用した実施機関 / Support Institute
北海道大学 / Hokkaido Univ.
機関外・機関内の利用 / External or Internal Use
外部利用/External Use
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）加工・デバイスプロセス/Nanofabrication（副 / Sub）計測・分析/Advanced Characterization
【重要技術領域 / Important Technology Area】（主 / Main）革新的なエネルギー変換を可能とするマテリアル/Materials enabling innovative energy conversion（副 / Sub）次世代ナノスケールマテリアル/Next-generation nanoscale materials
キーワード / Keywords
再生可能エネルギー材料、走査型電子顕微鏡、表面プラズモン共鳴,太陽電池/ Solar cell,電子顕微鏡/ Electronic microscope,スパッタリング/ Sputtering,ナノ粒子/ Nanoparticles
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
ZHAO Shuo
所属名 / Affiliation
School of Environment, Harbin Institute of Technology
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
Xu Shi,Yasutaka Matsuo,Hiroaki Misawa
利用形態 / Support Type
（主 / Main）機器利用/Equipment Utilization（副 / Sub）,共同研究/Joint Research
利用した主な設備 / Equipment Used in This Project
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
In 1979, Inoue et al. first demonstrated the photoelectrochemical reduction of aqueous carbon dioxide to produce formic acid, methane, et al., using semiconductor powders. [1] In this study, we propose using a nickel oxide (NiO) semiconductor as a photocathode and decorating it with metal nanoparticles to form a photocathodic electrode that can enhance photochemical reduction, such as hydrogen evolution, and carbon dioxide reduction, under visible light irradiation. NiO is a transition metal oxide material, which is transparent in the visible light band, but has strong absorption characteristics in the ultraviolet light band. To implement an effective photoreduction reaction, a p-type NiO thin film fabricated by sputtering was deposited on a Pt metal film. In this experiment, we mainly focus on optimizing the fabrication condition of NiO thin film deposited by the sputter.
実験 / Experimental
Quartz substrate with a size of 10.0x10.0x1.0 mm was washed with acetone, methanol, and pure water in a water bath, and then dried by N2 gas. A platinum film with a thickness of 100 nm was sputtered on the quartz glass by Multiple Target Sputtering (QAM-4-ST, ULVAC). Then, Ni was sputtered in an O2 atmosphere using the same equipment to form NiO thin film. The O2 partial pressure was controlled to optimize the quality of the NiO thin film. Post-annealing was also performed to improve the NiO thin film quantity. The surface morphology was observed by scanning electron microscopy (SU8230, Hitachi High-Tech). The crystallinity was measured by the X-ray diffraction (Smart lab, Rigaku). The photoelectrochemical properties were characterized using an electrochemical analyzer and a Xenon lamp light source.
結果と考察 / Results and Discussion
Figure 1a shows the SEM images of the NiO film before and after post-annealing. The NiO film was sputtered under a gas atmosphere of Ar (14.3 sccm) and O2 (0.7 sccm). The post-annealing was performed at 300oC for 5 hours. The SEM images show that the surface became flatter after post-annealing. The XRD spectra before and after post-annealing are shown in Figure 1b. The peaks of NiO crystal were observed in both before and after post-annealing. The NiO thin film was used as a photocathode and the photocurrent was measured under 350 nm light irradiation, as shown in Figure 1c. The cathodic photocurrent was observed and the photocurrent after post-annealing exhibits about 5-fold higher photocurrent than that before post-annealing. Though the incident photo-to-current conversion efficiency is still low, it has a large space to improve the photoelectrochemical properties by further optimizing the sputtering and post-annealing conditions. Next step, we will decorate metal nanoparticles on the NiO to enhance the photocurrent conversion efficiency in the visible region.
図・表・数式 / Figures, Tables and Equations
Figure 1. (a)The scanning electron micropy images of the NiO sureface. (b) The X-ray diffraction spectra of the NiO thin film. (c) The photocurrent of the NiO photocathode under 350 nm light irradiation.
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
Reference
[1] INOUE, T., FUJISHIMA, A., KONISHI, S. et al. Photoelectrocatalytic reduction of carbon dioxide in aqueous suspensions of semiconductor powders. Nature 277, 637–638 (1979).
Acknowledgements
A part of this work was supported by “Advanced Research Infrastructure for Materials and Nanotechnology in Japan (ARIM)” of the Ministry of Education, Culture, Sports, Science and Technology (MEXT). Proposal Number JPMXP1223HK0058.
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
特許 / Patents
特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件