Green synthesis of carbon coated macrostructured catalysts: Optimized methodology and enhanced catalytic performance

• Published in: Applied materials today Vol. 38; p. 102158
• Main Authors: Santos, A． Sofia G．G．, Restivo, João, Orge, Carla A., Pereira, M.Fernando R., Soares, O.Salomé G.P.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-06-2024
• Subjects: Green catalysis; Macrostructured catalysts; Novel methodology; Sodium alginate; Macrostructured catalysts; Novel methodology; Sodium alginate; Green catalysis
• ISSN: 2352-9407; 2352-9415
• DOI: 10.1016/j.apmt.2024.102158

•A novel methodology was developed for carbon macrostructured catalysts synthesis.•Sodium alginate was used as “green” dispersant.•Developed methodology allowed the synthesis of stable/active structured catalysts.•Adequate dispersant decomposition plays a key role for the catalyst stability.•Catalysts outperformed the results obtained with more established techniques.
A novel green and efficient synthesis methodology for carbon-coated macrostructured catalysts was assessed. Sodium alginate was used as a dispersant to promote a suitable dispersion of the modified carbon nanotubes (CNT) to be incorporated on a structured support. The coating conditions were optimized to synthesize active and stable carbon-coated macrostructured catalysts. Achieving a total dispersant decomposition was one of the key steps to guarantee the coating stability, 550 °C being the optimal temperature. To assess the catalytic activity for these catalysts, the carbon-coated structures were tested as main catalysts for oxalic acid degradation through ozonation, and as support for bimetallic Pd-Cu catalysts, applied in NO3− conversion. The results achieved during ozonation allowed to outperform the ones obtained with macrostructured catalysts synthesized by more established techniques (such as chemical vapor deposition) with oxalic acid degradation, in a continuous system, of around 75%. As for the bimetallic samples, the species proved to be quite dispersed on the catalyst support, allowing a NO3− conversion of around 20% with a corresponding N2 selectivity of 55%, outperforming, again, the same type of catalyst synthesized with “less green” surfactants. This newly developed methodology is an important step for the sustainability of the structured catalyst design area.
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