Preparation of g-C3N4 by self-assembled supramolecular precursor and its study of hydrogen production from photocatalytic water splitting
The structural regulation of photocatalysts is important to improve the efficiency of photocatalysis.g-C3N4 was prepared from melamine as raw material,and a series of MCx-g-C3N4(x is the molar ratio of melamine to cyanuric acid,and x=1,2,3 or 4)catalysts were prepared using melamine-cyanuric acid supramolecular as precursor.XRD,FT-IR,SEM,TEM,N2 adsorption/desorption,and XPS were used to characterize g-C3N4 and MCx-g-C3N4,and it is found that g-C3N4 and MCx-g-C3N4 exhibit different morphologies,structures,compositions and specific surface areas.Among them,MC3-g-C3N4 displays porous nanosheet structure with n(C element)∶n(N element)of 1.23,and the specific surface area is 45.63 m2/g,which is 4.5 times larger than that of g-C3N4.Using Pt as the co-catalyst and triethanolamine as the sacrificial agent,the catalytic performance of catalysts for hydrogen production from photocatalytic water splitting was investigated under visible light(≥ 400 nm).The results show that MC3-g-C3N4 shows the best catalytic performance for hydrogen production from photocatalytic water splitting,and its hydrogen production rate reaches 1127.83 pmol/(h g),which is 35 times higher than that of g-C3N4.The large surface area and porous structure of MC3-g-C3N4 provide more active sites for the reaction,and the nanosheet structure shorens the migration distance of photogenerated electrons to the catalyst surface,which promotes the separation of photogenerated electrons and holes,and thus significantly improving its catalytic performance for hydrogen production from photocatalytic water splitting.
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