Solvent Etching Process for Graphitic Carbon Nitride Photocatalysts Containing Platinum Cocatalyst: Effects of Water Hydrolysis on Photocatalytic Properties and Hydrogen Evolution Behaviors

• Published in: Nanomaterials (Basel, Switzerland) Switzerland), 2022-04, Vol.12 (7), p.1188
• Main Authors: Hoang, Thi Van Anh, Nguyen, Thi Kim Anh, Dao, Duc Quang, Nguyen, Phuong Anh, Jeong, Dong Hwi, Shin, Eun Woo
• Format: Article
• Language: English
• Subjects: Alternative energy; Carbon; Carbon nitride; Charge transfer; Electrodes; Etching; Ethanol; Fourier transforms; Functional groups; Hydrogen; Hydrogen evolution; Hydrogen production; hydrolysis; Microscopy; Mixtures; Morphology; Nitrogen; Optical properties; Oxidation; Photocatalysis; Photocatalysts; photocatalytic hydrogen evolution; Platinum; Pt/g-C3N4; Recombination; Renewable resources; solvent etching; Solvents; Spectrum analysis; Surface charge; Synthesis; tri-s-triazine unit; Triazine; Valence; water content
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano12071188

In this study, we synthesized Pt/g-C N photocatalysts modified by a solvent etching process where ethanol (Pt/CN0), water (Pt/CN100), and a 50:50 mixture (Pt/CN50) were used as a solvent, and investigated the optimal properties of g-C N to prepare the best Pt/g-C N for photocatalytic hydrogen evolution. From diverse characterizations, water was proven to be a stronger solvent agent, resulting in not only the introduction of more O-functional groups onto the g-C N surface, but also the degradation of a regular array of tri-s-triazine units in the g-C N structure. While the addition of O-functional groups positively influenced the oxidation state of the Pt cocatalyst and the hydrogen production rate, the changes to g-C N structure retarded charge transfer on its surface, inducing negative effects such as fast recombination and less oxidized Pt species. Pt/CN50 that was synthesized with the 50:50 solvent mixture exhibited the highest hydrogen production rate of 590.9 µmol g h , while the hydrogen production rates of Pt/CN0 (with pure ethanol solvent) and Pt/CN100 (with pure water solvent) were 462.7, and 367.3 µmol g h , respectively.