{"id":2287,"date":"2026-01-19T15:03:23","date_gmt":"2026-01-19T06:03:23","guid":{"rendered":"https:\/\/supraceramics.jp\/?p=2287"},"modified":"2026-01-19T15:03:23","modified_gmt":"2026-01-19T06:03:23","slug":"publication-j-phys-chem-lett-okazaki-maeda-sugimoto-katagiri-et-al-in-situ-x-ray-absorption-fine-structure-spectroscopy-measurement-of-suspended-cobalt-oxide-nanoparticle-water-ox","status":"publish","type":"post","link":"https:\/\/supraceramics.jp\/en\/2026\/01\/2287\/","title":{"rendered":"Publication | J. Phys. Chem. Lett. (Okazaki, Maeda, Sugimoto, Katagiri et al.) \u201cIn Situ X-ray Absorption Fine Structure Spectroscopy Measurement of Suspended Cobalt Oxide Nanoparticle Water Oxidation Catalyst\u201d"},"content":{"rendered":"<p>In Situ X-ray Absorption Fine Structure Spectroscopy Measurement of Suspended Cobalt Oxide Nanoparticle Water Oxidation Catalyst<\/p>\n<p>Megumi Okazaki,* Zi Lang Goo, Haruka Yamamoto, Kenta Ikegami, Issei Yamamoto, Naoki Tarutani, Fumitaka Takeiri, Takeshi Watanabe, Shunsuke Nozawa, Kiyofumi Katagiri, Kunihisa Sugimoto, Kazuhiko Maeda*<\/p>\n<p>Water oxidation using a heterogeneous catalyst under near-neutral pH conditions is of importance in artificial photosynthesis. This work assessed photochemical water oxidation over a supported cobalt oxide (CoO<sub><i>x<\/i><\/sub>) nanoparticle catalyst in the presence of Ru(II) trisdiimine as a photosensitizer and sodium persulfate as an electron acceptor, in both phosphate and borate buffer solutions at a pH of 7.9, using X-ray absorption fine structure spectroscopy (XAFS). The steady-state activity of the CoO<sub><i>x<\/i><\/sub> was found to be increased by a factor of 3\u22124 in the phosphate buffer. Co-<i>K<\/i> edge in situ XAFS measurement revealed that this catalyst maintained a high-valence CoOOH-like local structure during photoirradiation in the phosphate buffer. In contrast, CoOOH-like species rapidly formed in the borate buffer but remained stable for less than 40 min, with the subsequent generation of a mixture of Co<sup>2+<\/sup> and Co<sup>3+<\/sup> states with 4 and 6 coordination numbers. These results indicate that the phosphate buffer evidently promoted the generation and stabilization of active CoOOH species, thus facilitating water oxidation. The borate buffer failed to sustain these active species, resulting in lower catalytic activity. These insights provide a basis for the rational design of catalytic systems, emphasizing the importance of buffer-controlled local environments in sustaining active species for efficient water oxidation.<\/p>\n<p><a href=\"https:\/\/pubs.acs.org\/doi\/10.1021\/acs.jpclett.5c03125\">J. Phys. Chem. Lett. 2026, in press.<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>In Situ X-ray Absorption Fine Structure Spectroscopy Measurement of Suspended Cobalt Oxide Nanoparticle Water Oxidation Catalyst Megumi Okazaki,* Zi Lang Goo, Haruka Yamamoto, Kenta Ikegami, Issei Yamamoto, Naoki Tarutani, Fumitaka Takeiri, Takeshi Watanabe, Shunsuke Nozawa, Kiyofumi Katagiri, Kunihisa Sugimoto, Kazuhiko Maeda* Water oxidation using a heterogeneous catalyst under near-neutral pH conditions is of importance in [&hellip;]<\/p>\n","protected":false},"author":222414606,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"jetpack_seo_schema_type":"","_themeisle_gutenberg_block_has_review":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_locale":"en_US","_original_post":"https:\/\/supraceramics.jp\/?p=2285","_wpcom_ai_launchpad_first_post":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[124830],"tags":[],"class_list":["post-2287","post","type-post","status-publish","format-standard","hentry","category-news","en-US"],"jetpack_publicize_connections":[],"jetpack_shortlink":"https:\/\/wp.me\/pe2JgX-AT","jetpack-related-posts":[{"id":2285,"url":"https:\/\/supraceramics.jp\/2026\/01\/2285\/","url_meta":{"origin":2287,"position":0},"title":"Publication | J. Phys. Chem. Lett. (Okazaki, Maeda, Sugimoto, Katagiri et al.) \u201cIn Situ X-ray Absorption Fine Structure Spectroscopy Measurement of Suspended Cobalt Oxide Nanoparticle Water Oxidation Catalyst\u201d","author":"shorike","date":"2026\u5e741\u670819\u65e5","format":false,"excerpt":"In Situ X-ray Absorption Fine Structure Spectroscopy Measurement of Suspended Cobalt Oxide Nanoparticle Water Oxidation Catalyst Megumi Okazaki,* Zi Lang Goo, Haruka Yamamoto, Kenta Ikegami, Issei Yamamoto, Naoki Tarutani, Fumitaka Takeiri, Takeshi Watanabe, Shunsuke Nozawa, Kiyofumi Katagiri, Kunihisa Sugimoto, Kazuhiko Maeda* \u9178\u5316\u30b3\u30d0\u30eb\u30c8\u30ca\u30ce\u7c92\u5b50(CoOx)\u306f\u3001\u5149\u89e6\u5a92\u3092\u7528\u3044\u305f\u6c34\u306e\u9178\u5316\u53cd\u5fdc\u306b\u304a\u3044\u3066\u53cd\u5fdc\u6d3b\u6027\u70b9\u3068\u3057\u3066\u4f5c\u7528\u3057\u307e\u3059\u3002\u672c\u7814\u7a76\u3067\u306f\u3001CoOx\u3092\u4fee\u98fe\u3057\u305fTiO2\u7c89\u672b\u3092\u6c34\u6eb6\u6db2\u4e2d\u306b\u61f8\u6fc1\u3055\u305b\u305f\u72b6\u614b\u3067\u3001\u6c34\u306e\u5149\u9178\u5316\u53cd\u5fdc\u4e2d\u306b\u304a\u3051\u308bCoOx\u306e\u5316\u5b66\u72b6\u614b\u3092in situ XAFS\u6e2c\u5b9a\u3092\u7528\u3044\u3066\u8ffd\u8de1\u3059\u308b\u3053\u3068\u306b\u6210\u529f\u3057\u307e\u3057\u305f\u3002\u3053\u306e\u6e2c\u5b9a\u624b\u6cd5\u306e\u78ba\u7acb\u306b\u3088\u308a\u3001\u52a9\u89e6\u5a92\u62c5\u6301\u5149\u89e6\u5a92\u306e\u53cd\u5fdc\u306b\u304a\u3051\u308b\u52a9\u89e6\u5a92\u306e\u72b6\u614b\u3092\u30ea\u30a2\u30eb\u30bf\u30a4\u30e0\u306b\u8abf\u67fb\u3059\u308b\u3053\u3068\u304c\u53ef\u80fd\u3068\u306a\u308a\u3001\u5149\u89e6\u5a92\u306e\u53cd\u5fdc\u5834\u306e\u771f\u306e\u6d3b\u6027\u7a2e\u3092\u6349\u3048\u3089\u308c\u308b\u3053\u3068\u304c\u671f\u5f85\u3055\u308c\u307e\u3059\u3002\u672c\u6210\u679c\u306f\u3001J. Phys. Chem. Lett.\u8a8c\u306b\u30aa\u30f3\u30e9\u30a4\u30f3\u63b2\u8f09\u3055\u308c\u307e\u3057\u305f\u3002 J. Phys. Chem.\u2026","rel":"","context":"In &quot;News&quot;","block_context":{"text":"News","link":"https:\/\/supraceramics.jp\/en\/category\/news\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1845,"url":"https:\/\/supraceramics.jp\/en\/2024\/11\/1845\/","url_meta":{"origin":2287,"position":1},"title":"Publication | Chem Catal. (Okazaki, Maeda et al.) \u201cDiscovery of the threshold potential that triggers photochemical water oxidation with Ru(II) photosensitizers and MOx catalysts\u201d","author":"shorike","date":"2024\u5e7411\u670813\u65e5","format":false,"excerpt":"Discovery of the threshold potential that triggers photochemical water oxidation with Ru(II) photosensitizers and MOx catalysts Megumi Okazaki*, Yasuomi Yamazaki, Daling Lu, Shunsuke Nozawa, Osamu Ishitani, Kazuhiko Maeda* This work focuses on a traditional, well-known photochemical water oxidation system that uses a Ru(II) tris-2,2\u2032-bipyridine photosensitizer and transition-metal oxide catalysts, which\u2026","rel":"","context":"In &quot;News&quot;","block_context":{"text":"News","link":"https:\/\/supraceramics.jp\/en\/category\/news\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":2253,"url":"https:\/\/supraceramics.jp\/en\/2025\/12\/2253\/","url_meta":{"origin":2287,"position":2},"title":"Publication | ACS Catal. (Maeda, Onda et al.) \u201cCharge Transfer Dynamics in Dye-Sensitized Photocatalysts Using Metal Complex Sensitizers with Long-Wavelength Visible Light Absorption Based on Singlet\u2013Triplet Excitation\u201d","author":"shorike","date":"2025\u5e7412\u67086\u65e5","format":false,"excerpt":"Charge Transfer Dynamics in Dye-Sensitized Photocatalysts Using Metal Complex Sensitizers with Long-Wavelength Visible Light Absorption Based on Singlet\u2013Triplet Excitation Haruka Yamamoto, Toshiya Tanaka, Masahito Oura, Kelly M. Kopera, Megumi Okazaki, Ken Onda, Thomas E. Mallouk,* Kazuhiko Maeda* An Os(II) polypyridyl complex was applied as a photosensitizer in dye-sensitized photocatalyst systems\u2026","rel":"","context":"In &quot;News&quot;","block_context":{"text":"News","link":"https:\/\/supraceramics.jp\/en\/category\/news\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":2238,"url":"https:\/\/supraceramics.jp\/en\/2025\/12\/2238\/","url_meta":{"origin":2287,"position":3},"title":"Symposium in Pacifichem 2025, 12\/17 (Wed)","author":"shorike","date":"2025\u5e7412\u67083\u65e5","format":false,"excerpt":"Pacifichem 2025 ~Inorganic Materials with Multiple Components for Energy and Environmental Applications\uff08ING016\uff09~ 12\/17 (Wed), 2025 Hilton Hawaiian Village Organizers: Ryo Ohtani, Jeongsuk Seo, Lianzhou Wang,\u00a0Kazuhiko Maeda \u00a0 Program: 8:00\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ~Opening Remarks~ 8:05\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Solution Chemistry Engineering for Efficient Kesterite Solar Cells and Modules Xin, Hao (Nanjing University of Posts and Telecommunications)\u2026","rel":"","context":"In &quot;News&quot;","block_context":{"text":"News","link":"https:\/\/supraceramics.jp\/en\/category\/news\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":2232,"url":"https:\/\/supraceramics.jp\/2025\/12\/2232\/","url_meta":{"origin":2287,"position":4},"title":"Symposium in Pacifichem 2025, 12\/17 (Wed)","author":"shorike","date":"2025\u5e7412\u67083\u65e5","format":false,"excerpt":"Pacifichem 2025 ~Inorganic Materials with Multiple Components for Energy and Environmental Applications\uff08ING016\uff09~ 12\/17 (Wed), 2025 Hilton Hawaiian Village Organizers: Ryo Ohtani, Jeongsuk Seo, Lianzhou Wang,\u00a0Kazuhiko Maeda \u00a0 Program: 8:00\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ~Opening Remarks~ 8:05\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Solution Chemistry Engineering for Efficient Kesterite Solar Cells and Modules Xin, Hao (Nanjing University of Posts and Telecommunications)\u2026","rel":"","context":"In &quot;News&quot;","block_context":{"text":"News","link":"https:\/\/supraceramics.jp\/en\/category\/news\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":2312,"url":"https:\/\/supraceramics.jp\/en\/2026\/02\/2312\/","url_meta":{"origin":2287,"position":5},"title":"Publication | Chem. Mater. (Motohashi, Sugimoto, et al.) \u201cUnconventional Oxygen Storage\/Release Properties of Melilite-Type Ba2MnGe2O7+\u03b4 Associated with Complex Structural Transformation\u201d","author":"shorike","date":"2026\u5e742\u670816\u65e5","format":false,"excerpt":"Unconventional Oxygen Storage\/Release Properties of Melilite-Type Ba2MnGe2O7+\uf064 Associated with Complex Structural Transformation Kosaku Ohishi, Satoshi Ogawa, Hisanori Yamane, Saburo Hosokawa, Zi Lang Goo, Kunihisa Sugimoto, Miwa Saito, Teruki Motohashi Here, we report the synthesis and characterization of melilite-type A2MnC2O7 (A = Sr, Ba; C = Si, Ge) and the discovery\u2026","rel":"","context":"In &quot;News&quot;","block_context":{"text":"News","link":"https:\/\/supraceramics.jp\/en\/category\/news\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/supraceramics.jp\/wp-json\/wp\/v2\/posts\/2287","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/supraceramics.jp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/supraceramics.jp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/supraceramics.jp\/wp-json\/wp\/v2\/users\/222414606"}],"replies":[{"embeddable":true,"href":"https:\/\/supraceramics.jp\/wp-json\/wp\/v2\/comments?post=2287"}],"version-history":[{"count":1,"href":"https:\/\/supraceramics.jp\/wp-json\/wp\/v2\/posts\/2287\/revisions"}],"predecessor-version":[{"id":2288,"href":"https:\/\/supraceramics.jp\/wp-json\/wp\/v2\/posts\/2287\/revisions\/2288"}],"wp:attachment":[{"href":"https:\/\/supraceramics.jp\/wp-json\/wp\/v2\/media?parent=2287"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/supraceramics.jp\/wp-json\/wp\/v2\/categories?post=2287"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/supraceramics.jp\/wp-json\/wp\/v2\/tags?post=2287"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}