{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,22]],"date-time":"2026-01-22T08:55:41Z","timestamp":1769072141089,"version":"3.49.0"},"reference-count":32,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2022,2,15]],"date-time":"2022-02-15T00:00:00Z","timestamp":1644883200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["UIDB\/50020\/2020"],"award-info":[{"award-number":["UIDB\/50020\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["UIDP\/50020\/2020"],"award-info":[{"award-number":["UIDP\/50020\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["POCI-01-0145-FEDER-030674"],"award-info":[{"award-number":["POCI-01-0145-FEDER-030674"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["POCI-01-0145-FEDER-031398"],"award-info":[{"award-number":["POCI-01-0145-FEDER-031398"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004895","name":"European Social Fund","doi-asserted-by":"publisher","award":["NORTE-08-5369-FSE-000028"],"award-info":[{"award-number":["NORTE-08-5369-FSE-000028"]}],"id":[{"id":"10.13039\/501100004895","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Vitamin B3 (nicotinic acid, VB3) was synthesized through the photocatalytic oxidation of 3-pyridinemethanol (3PM) under visible-light-emitting diode (LED) irradiation using metal-free graphitic carbon nitride (GCN) - based materials. A bulk (GCN) material was prepared by a simple thermal treatment using dicyandiamide as the precursor. A post-thermal treatment under static air and nitrogen flow was employed to obtain the GCN-T and GCN-T-N materials, respectively. The conditions adopted during the post-treatment revealed differences in the resulting materials\u2019 morphological, electronic, and optical properties. The post-treated photocatalysts revealed an enhanced efficiency in the oxidation of 3PM into VB3, with the GCN-T-N photocatalyst being the best-performing material. The defective surface, reduced crystallinity, and superior photoabsorption of GCN-T-N account for this material\u2019s improved performance in the production of VB3. Nevertheless, the presence of nitrogen vacancies in the carbon nitride structure and, consequently, the creation of mid-gap states also accounts to its highly oxidative ability. The immobilization of GCN-T-N in sodium alginate hydrogel was revealed as a promising strategy to produce VB3, avoiding the need for the photocatalyst separation step. Concerning the mechanism of synthesis of VB3 through the photocatalytic oxidation of 3PM, it was possible to identify the presence of 3-pyridinecarboxaldehyde (3PC) as the intermediary product.<\/jats:p>","DOI":"10.3390\/molecules27041295","type":"journal-article","created":{"date-parts":[[2022,2,15]],"date-time":"2022-02-15T22:44:47Z","timestamp":1644965087000},"page":"1295","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Synthesis of Vitamin B3 through a Heterogeneous Photocatalytic Approach Using Metal-Free Carbon Nitride-Based Catalysts"],"prefix":"10.3390","volume":"27","author":[{"given":"Raquel A.","family":"Fernandes","sequence":"first","affiliation":[{"name":"ALiCE\u2013Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"LSRE-LCM \u2013 Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials, Faculty of Engineering, University of Porto, Rua Dr. Roberto s\/n, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5206-5146","authenticated-orcid":false,"given":"Maria J.","family":"Sampaio","sequence":"additional","affiliation":[{"name":"ALiCE\u2013Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"LSRE-LCM \u2013 Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials, Faculty of Engineering, University of Porto, Rua Dr. Roberto s\/n, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6531-3978","authenticated-orcid":false,"given":"Joaquim L.","family":"Faria","sequence":"additional","affiliation":[{"name":"ALiCE\u2013Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"LSRE-LCM \u2013 Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials, Faculty of Engineering, University of Porto, Rua Dr. Roberto s\/n, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6469-4871","authenticated-orcid":false,"given":"Cl\u00e1udia G.","family":"Silva","sequence":"additional","affiliation":[{"name":"ALiCE\u2013Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"LSRE-LCM \u2013 Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials, Faculty of Engineering, University of Porto, Rua Dr. Roberto s\/n, 4200-465 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2022,2,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1016\/j.apcata.2004.08.029","article-title":"Technology development in nicotinate production","volume":"280","author":"Chuck","year":"2005","journal-title":"Appl. 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