Development of novel photocatalyst directed toward the reduction of CO2 in air

• Project/Area Number: 20K05686
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 36020:Energy-related chemistry
• Research Institution: Kyoto University
• Principal Investigator: KAJIWARA Takashi 京都大学, 高等研究院, 特定研究員 (80422799)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2022: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2021: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2020: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: 二酸化炭素還元 / 多孔性配位高分子 / 光触媒 / 物質分離 / 多孔性金属錯体

Outline of Research at the Start

二酸化炭素 (CO2) を有用な物質に再資源化する人工光合成系の開発に期待が持たれているが，天然の光合成系に比べると未だ改善すべき点が多い．特に，天然光合成系が空気中にごくわずかに含まれるCO2を原料にしていることは，既報の人工光合成系が高濃度のCO2の使用を前提としていることと対照的である．本研究では，CO2分離・濃縮機能に優れた多孔性金属錯体 (PCP/MOF) に着目し，空気中のCO2還元の実現を志向した革新的な光触媒を創製する．

Outline of Final Research Achievements

To achieve the sustainable development goals, CO2 reduction into high value-added molecules utilizing renewable energy is one of the most important research topics. In this study, composite catalysts based on porous coordination polymers and molecular complex catalysts were synthesized and characterized. The composite catalysts showed unusual CO2 reduction reactivity, which most probably results from the synergistic effect between the CO2 enrichment in the micropores and the CO2 reduction at the wall of the pore.

Academic Significance and Societal Importance of the Research Achievements

人工光合成の開発は高純度の二酸化炭素を原料ガスとして使用することを前提として進められてきたが，二酸化炭素は通常排ガスをはじめ空気など常に低濃度の混合ガスとして存在しており，高純度ガスを得るための精製過程には莫大なエネルギーが必要となる．本研究では，二酸化炭素の分離・濃縮と還元反応とを多孔性配位高分子のミクロ孔中で一度に行うことにより，このような精製過程を必要とせずに混合ガスのまま反応に供することができるということを明らかにした点で，空気を直接利用する天然光合成に一歩近づく成果であり，精製コストの削減などの観点からも大きな意義を持つ．

Research Products

• [Int'l Joint Research] CNRS(フランス)
• [Int'l Joint Research] SUSTech(中国)
• [Int'l Joint Research] CNRS(フランス)
• [Int'l Joint Research] SUSTech(中国)
• [Int'l Joint Research] Karunya Institute(インド)
• [Journal Article] Photoinduced Catalytic Organic‐Hydride Transfer to CO2 Mediated with Ruthenium Complexes as NAD+/NADH Redox Couple Models (2023)
  • Author(s): Kinoshita Yusuke、Deromachi Nagisa、Kajiwara Takashi、Koizumi Take‐aki、Kitagawa Susumu、Tamiaki Hitoshi、Tanaka Koji
  • Journal Title: ChemSusChem Volume: 16 Issue: 6
  • DOI: 10.1002/cssc.202300032
  • Peer Reviewed / Open Access
• [Journal Article] Ultrasmall Copper Nanoclusters in Zirconium Metal-Organic Frameworks for the Photoreduction of CO2 (2022)
  • Author(s): Shan Dai, Takashi Kajiwara, Miyuki Ikeda, Ignacio Romero-Muniz, Gilles Patriarche, Ana E. Platero-Prats, Alexandre Vimont, Marco Daturi, Antoine Tissot, Qiang Xu, Christian Serre
  • Journal Title: Angewandte Chemie International Edition Volume: 61 Issue: 43
  • DOI: 10.1002/anie.202211848
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Fine Pore‐Structure Engineering by Ligand Conformational Control of Naphthalene Diimide‐Based Semiconducting Porous Coordination Polymers for Efficient Chemiresistive Gas Sensing (2022)
  • Author(s): Xue Ziqian、Zheng Jia‐Jia、Nishiyama Yusuke、Yao Ming‐Shui、Aoyama Yoshitaka、Fan Zeyu、Wang Ping、Kajiwara Takashi、Kubota Yoshiki、Horike Satoshi、Otake Ken‐ichi、Kitagawa Susumu
  • Journal Title: Angewandte Chemie International Edition Volume: 62 Issue: 2
  • DOI: 10.1002/anie.202215234
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Effect of Micropores of a Porous Coordination Polymer on the Product Selectivity in Ru(II) Complex‐catalyzed CO2 Reduction (2021)
  • Author(s): Takashi Kajiwara, Miyuki Ikeda, Katsuaki Kobayashi, Masakazu Higuchi, Koji Tanaka, Susumu Kitagawa
  • Journal Title: Chemistry - An Asian Journal Volume: 16 Issue: 21 Pages: 3341-3344
  • DOI: 10.1002/asia.202100813
  • Peer Reviewed
• [Journal Article] Xylene Recognition in Flexible Porous Coordination Polymer by Guest-Dependent Structural Transition (2021)
  • Author(s): Wang Ping、Kajiwara Takashi、Otake Ken-ichi、Yao Ming-Shui、Ashitani Hirotaka、Kubota Yoshiki、Kitagawa Susumu
  • Journal Title: ACS Applied Materials & Interfaces Volume: 13 Issue: 44 Pages: 52144-52151
  • DOI: 10.1021/acsami.1c10061
  • Peer Reviewed
• [Journal Article] Ligand-Assisted Electrochemical CO2 Reduction by Ru-Polypyridyl Complexes (2020)
  • Author(s): Debashis Ghosh, Takashi Kajiwara, Susumu Kitagawa, Koji Tanaka
  • Journal Title: European Journal of Inorganic Chemistry Volume: 2020 Issue: 18 Pages: 1814-1818
  • DOI: 10.1002/ejic.202000259
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Photochemical CO2 reduction with ruthenium(II)-complex catalysts inside the micropores of porous coordination polymers (2022)
  • Author(s): Takashi Kajiwara
  • Organizer: 錯体化学会第72回討論会 Symposium S3
  • Invited
• [Remarks] ルテニウム錯体を触媒とする有機ヒドリドを介した二酸化炭素光還元 新たな人工光合成系の創製に向けて
  • URL: https://www.icems.kyoto-u.ac.jp/news/7711/