Photocatalytic Synthesis of Ammonia from Pinecone Graphite-Phase Carbon Nitride Loaded with MoS2 Nanosheets as Co-catalysts.

Abstract

Photocatalytic nitrogen fixation is a promising alternative to the Haber-Bosch process to alleviate the energy and environmental crises. Here, we designed a pinecone-shaped graphite-phase carbon nitride (PCN) catalyst supported with MoS2 nanosheets by a supramolecular self-assembly method. The catalyst shows an excellent photocatalytic nitrogen reduction reaction (PNRR) due to the larger specific surface area and the enhancement of visible light owing to the reduced band gap. Under simulated sunlight, the sample of PCN loaded with 5 wt % MoS2 nanosheets (MS5%/PCN) shows a PNRR efficiency of 279.41 μmol g-1 h-1, which is 14.9 times that of bulk graphite-phase carbon nitride (g-C3N4), 4.6 times that of PCN, and 5.4 times that of MoS2, respectively. The unique pinecone-like structure of MS5%/PCN not only improves the ability of light absorption but also assists in the uniform loading of MoS2 nanosheets. Likewise, the existence of MoS2 nanosheets improves the light absorption ability of the catalyst and reduces the impedance of the catalyst. Furthermore, as a co-catalyst, MoS2 nanosheets can efficiently adsorb nitrogen (N2) and serve as active N2 reduction sites. From the perspective of structural design, this work can offer novel solutions for the creation of effective N2-fixing photocatalysts.