{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T07:08:21Z","timestamp":1788851301622,"version":"build-2803163510"},"reference-count":35,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,9,7]],"date-time":"2026-09-07T00:00:00Z","timestamp":1788739200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,9,7]],"date-time":"2026-09-07T00:00:00Z","timestamp":1788739200000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/100019642","name":"Samco Foundation","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100019642","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Small"],"abstract":"ABSTRACT<\/jats:title>\n \n The efficiency of one\u2010step and Z\u2010scheme photocatalytic water\u2010splitting systems is often limited by undesired reverse reactions, such as water formation from H\n 2<\/jats:sub>\n and O\n 2<\/jats:sub>\n , oxygen reduction, and backward electron transfer to redox mediators. Although coating noble metal cocatalysts (e.g., Pt) with a CrO\n \n x<\/jats:sub>\n <\/jats:italic>\n shell can effectively suppress these reactions, conventional CrO\n \n x<\/jats:sub>\n <\/jats:italic>\n shell formation methods use toxic Cr(VI) precursors. To overcome this issue, CrCl\n 3<\/jats:sub>\n , a previously overlooked low\u2010toxicity Cr(III) precursor, is demonstrated to construct a superior noble metal core \u2500CrO\n \n x<\/jats:sub>\n <\/jats:italic>\n shell via a distinct mechanism. Structural analyses reveal that CrCl\n 3<\/jats:sub>\n forms a highly uniform CrO\n \n x<\/jats:sub>\n <\/jats:italic>\n shell that is thinner (\u223c1.2\u00a0nm) than conventional K\n 2<\/jats:sub>\n CrO\n 4<\/jats:sub>\n \u2010derived shells (\u223c1.7\u00a0nm). Electrochemical studies suggest a novel deposition pathway involving a Cr(III) \u2192 Cr(VI) \u2192 Cr(III) redox cycle, wherein transiently generated Cr(VI) species allow for thickness control. Consequently, the CrCl\n 3<\/jats:sub>\n \u2010derived Pt\u2013CrO\n \n x<\/jats:sub>\n <\/jats:italic>\n core\u2013shell cocatalyst effectively suppresses backward electron transfer toward redox mediators while preserving high intrinsic H\n 2<\/jats:sub>\n evolution activity. In a visible\u2010light\u2010driven Z\u2010scheme water\u2010splitting system, the photocatalyst loaded with the CrCl\n 3<\/jats:sub>\n \u2010derived core\u2013shell cocatalyst exhibits higher H\n 2<\/jats:sub>\n and O\n 2<\/jats:sub>\n evolution rates than that loaded with the K\n 2<\/jats:sub>\n CrO\n 4<\/jats:sub>\n \u2010derived counterpart, with sustained stability. This work establishes CrCl\n 3<\/jats:sub>\n as an effective, eco\u2010friendly alternative for high\u2010performance core\u2013shell cocatalysts.\n <\/jats:p>","DOI":"10.1002\/smll.75648","type":"journal-article","created":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T06:29:51Z","timestamp":1788848991000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Uniform CrO\n \n x<\/sub>\n <\/i>\n Shells on Pt Cocatalyst Derived from Low\u2010Toxicity Cr(III) Precursor for Improved Photocatalytic Water Splitting"],"prefix":"10.1002","author":[{"given":"Xinru","family":"Sui","sequence":"first","affiliation":[{"name":"Department of Energy and Hydrocarbon Chemistry Graduate School of Engineering Kyoto University Katsura Nishikyo\u2010ku Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8891-2033","authenticated-orcid":false,"given":"Hajime","family":"Suzuki","sequence":"additional","affiliation":[{"name":"Department of Energy and Hydrocarbon Chemistry Graduate School of Engineering Kyoto University Katsura Nishikyo\u2010ku Japan"},{"name":"Precursory Research for Embryonic Science and Technology (PRESTO) Japan Science and Technology Agency (JST) Kawaguchi Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Keisuke","family":"Morikawa","sequence":"additional","affiliation":[{"name":"Department of Energy and Hydrocarbon Chemistry Graduate School of Engineering Kyoto University Katsura Nishikyo\u2010ku Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Osamu","family":"Tomita","sequence":"additional","affiliation":[{"name":"Department of Energy and Hydrocarbon Chemistry Graduate School of Engineering Kyoto University Katsura Nishikyo\u2010ku Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6670-5044","authenticated-orcid":false,"given":"Akinobu","family":"Nakada","sequence":"additional","affiliation":[{"name":"Department of Energy and Hydrocarbon Chemistry Graduate School of Engineering Kyoto University Katsura Nishikyo\u2010ku Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4977-6849","authenticated-orcid":false,"given":"Shunsuke","family":"Nozawa","sequence":"additional","affiliation":[{"name":"Photon Factory (PF) Institute of Materials Structure Science (IMSS) High Energy Accelerator Research Organization (KEK) Tsukuba Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8592-076X","authenticated-orcid":false,"given":"Ryu","family":"Abe","sequence":"additional","affiliation":[{"name":"Department of Energy and Hydrocarbon Chemistry Graduate School of Engineering Kyoto University Katsura Nishikyo\u2010ku Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,9,7]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1038\/238037a0","article-title":"Electrochemical Photolysis of Water at a Semiconductor Electrode","volume":"238","author":"Fujishima A.","year":"1972","journal-title":"Nature"},{"key":"e_1_2_9_3_1","doi-asserted-by":"crossref","first-page":"919","DOI":"10.1021\/acs.chemrev.9b00201","article-title":"Particulate Photocatalysts for Light\u2010Driven Water Splitting: Mechanisms, Challenges, and Design Strategies","volume":"120","author":"Wang Q.","year":"2020","journal-title":"Chemical Reviews"},{"key":"e_1_2_9_4_1","doi-asserted-by":"crossref","first-page":"5201","DOI":"10.1021\/acs.chemrev.7b00286","article-title":"Mimicking Natural Photosynthesis: Solar to Renewable H2 Fuel Synthesis by Z\u2010Scheme Water Splitting Systems","volume":"118","author":"Wang Y. 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