科研之友
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摘要
The molten salt-assisted route is one of the most important methods to improve the crystallinity of conventionally disordered bulk graphitic carbon nitride (g-C3N4). However, the residual potassium ions from potassium chloride/lithium chloride molten salt can greatly impact the ordered structure of g-C3N4 and serve as the recombination centers of photoinduced carriers, causing limited photocatalytic hydrogenevolution performance. In this article, the ethyl acetate-mediated method is first developed to not only further improve the ordered structure of traditional crystalline g-C3N4, but also produce more cyano groups for preparing highly efficient g-C3N4 photocatalysts. Herein, the ethyl acetate can gradually hydrolyze to produce hydrogen ions, which can promote the more ordered sheet-like structure and more cyano groups by effective removal of residual potassium ions in the traditional crystalline g-C3N4, leading to the formation of cyano group-enriched crystalline g-C3N4 photocatalysts (CC-CN). As a result, the resultant CC-CN displays the remarkably enhanced photocatalytic hydrogen-evolution performance (295.30 mmol h-1 with an apparent quantum efficiency about 12.61%), in comparison to the bulk g-C3N4 (14.97 mmol h-1) and traditional crystalline g-C3N4 (24.60 mmol h-1). The great improvement of photocatalytic performance can mainly be ascribed to the synergism of improved ordered structure and abundant cyano groups, namely, the efficient transfer , separation of photoinduced charges as well as excellent interfacial hydrogen-generation reaction, respectively. The present work may deliver new strategies to prepare other high-crystalline photocatalysts with great efficiency.
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单位郑州大学; 武汉理工大学; 桂林理工大学
