Tailoring the Grain Boundary Chemistry of Polymeric Carbon Nitride for Enhanced Solar Hydrogen Production and CO2 Reduction

• Published in: Angewandte Chemie International Edition Vol. 58; no. 11; pp. 3433 - 3437
• Main Authors: Zhang, Guigang, Li, Guosheng, Heil, Tobias, Zafeiratos, Spiros, Lai, Feili, Savateev, Aleksandr, Antonietti, Markus, Wang, Xinchen
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 11.03.2019
• Edition: International ed. in English
• Subjects: Carbon; Carbon dioxide; carbon dioxide reduction; Carbon nitride; Chemical reduction; Grain boundaries; Hydrogen production; Localization; Molten salts; Organic chemistry; Oxidation; photocatalysis; Photosynthesis; polymeric carbon nitride; Potassium chloride; Potassium phosphate; Potassium phosphates; Quantum efficiency; Sodium chloride; Solar energy; Water splitting
• DOI: 10.1002/anie.201811938
• ISSN: 1433-7851; 1521-3773

Photocatalytic water splitting is a promising and clean way to mimic plant photosynthesis in a sustainable manner. Improvements of the quantum efficiency and optical absorption in the relevant range are necessary steps to approach practicality. Herein, we reported that these issues can be readily addressed when 5‐aminotetrazole, a monomer with high nitrogen content, is used for the synthesis of carbon nitride. The molten salt mixture NaCl/KCl is used as a high‐temperature solvent to tailor the grain boundary structure and chemistry. Visible light quantum efficiency for H2 production of 0.65 could be obtained in the presence of K2HPO4 as a double layer modifier. This value is very high, considering that this number depends on light to charge couple conversion, charge localization, as well as a successful oxidation and reduction reaction. Polymeric carbon nitride with enhanced optical absorption and photocatalytic activities is synthesized via a one‐pot ionothermal polymerization of 5‐aminotetrazole in eutectic NaCl/KCl. This approach allows control of the polymerization process and tailoring of the grain boundary structure and catalytic properties.