A direct one-step synthesis of ultrathin g-C3N4 nanosheets from thiourea for boosting solar photocatalytic H2 evolution

By Yuanzhi Hong, Enli Liu, Junyou Shi, Xue Lin, Lizhi Sheng, M. Zhang, Longyan Wang, Jiahui Chen. International journal of hydrogen energy, 2019

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Abstract Two-dimensional (2D) graphitic carbon nitride (g-C3N4) nanosheets, as the promising photocatalyst with fascinating properties, have become a “rising star” in the field of photocatalysis. Although g-C3N4 nanosheets exfoliated from the bulk g-C3N4 powders are extensively emerged, developing a simple synthetic approach is still full of challenge. To this end, here we report a direct polymerization strategy to fabricate the ultrathin g-C3N4 nanosheets, that is only heating treatment of thiourea in air without addition of any template. The photocatalytic activities of as-prepared samples were evaluated by photoreduction of water to hydrogen (H2) using triethanolamine as sacrificial agent and Pt as co-catalyst under visible-light irradiation (λ > 420 nm). As a result, our few-layered g-C3N4 nanosheets with an average thickness of 3.5 nm exhibit a superior visible-light photocatalytic H2 evolution rate (HER) of 1391 μmol g−1 h−1 and a remarkable apparent quantum efficiency of 6.6% at 420 nm. Eventually, the HER of as-fabricated ultrathin g-C3N4 nanosheets is not only much higher than the dicyandiamide-derived g-C3N4 or melamine-derived g-C3N4, but also greater than the thermal-oxidation etched g-C3N4 nanosheets under the same condition.

Subfields: Electrical and Electronic Engineering, Materials Chemistry, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/747e5c6cfcd5cc8268cb6b800efd760055097459