Tug-of-War Driven by the Structure of Carboxylic Acids: Tuning the Size, Morphology, and Photocatalytic Activity of α-Ag2WO4

• Published in: Nanomaterials (Basel, Switzerland) Vol. 12; no. 19; p. 3316
• Main Authors: Ribeiro, Lara Kelly, Gouveia, Amanda Fernandes, Silva, Francisco das Chagas M., Noleto, Luís F. G., Assis, Marcelo, Batista, André M., Cavalcante, Laécio S., Guillamón, Eva, Rosa, Ieda L. V., Longo, Elson, Andrés, Juan, Luz Júnior, Geraldo E.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 23-09-2022; MDPI
• Subjects: Carboxylic acids; Catalysis; Catalytic activity; Chemical synthesis; Citric acid; controlled size and morphology; Crystal surfaces; Crystallization; Dehydration; Growth rate; Hydroxyl radicals; Ligands; Morphology; Nucleation; Photocatalysis; photocatalytic activity; Photodegradation; Recyclability; Rhodamine; sonochemical synthesis; Spectrum analysis; α-Ag2WO4; United States > US
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano12193316

Size and morphology control during the synthesis of materials requires a molecular-level understanding of how the addition of surface ligands regulates nucleation and growth. In this work, this control is achieved by using three carboxylic acids (tartaric, benzoic, and citric) during sonochemical syntheses. The presence of carboxylic acids affects the kinetics of the nucleation process, alters the growth rate, and governs the size and morphology. Samples synthesized with citric acid revealed excellent photocatalytic activity for the degradation process of Rhodamine B, and recyclability experiments demonstrate that it retains 91% of its photocatalytic activity after four recycles. Scavenger experiments indicate that both the hydroxyl radical and the hole are key species for the success of the transformation. A reaction pathway is proposed that involves a series of dissolution−hydration–dehydration and precipitation processes, mediated by the complexation of Ag+. We believe these studies contribute to a fundamental understanding of the crystallization process and provide guidance as to how carboxylic acids can influence the synthesis of materials with controlled size and morphology, which is promising for multiple other scientific fields, such as sensor and catalysis fields.