The Study On Ni-P Modified G-C₃N₄ Photocatalysts On Enhanced Water Splitting For Hydrogen Production

A simple liquid-phase reduction method has been reported to prepare the Pt/g-C₃N₄ composites with different loading amount of Pt nanoparticles?NPs?.These Pt/g-C₃N₄ composites have a better photocatalytic performance than pure g-C₃N₄offering for water splitting into hydrogen.The Pt NPs are uniformly spread on g-C3N4surfaces,with their diameters in the range of 4⁸ nanometers.Loading of Pt NPs can expand the response of visible light for g-C₃N₄ and reduce the recombination rate of photogenerated carriers.Therefore,the performance of water splitting into hydrogen via g-C₃N₄ photocatalysis under sunlight is enhanced by using the cocatalyst of Pt.Pt/g-C₃N₄?3wt%of Pt?shows the highest activity(841?mol g^-1h^-1)among the as-prepared samples,while the pure g-C3N4 almost no hydrogen production.Over loading of Pt will decrease the photocatalytic activity,for example,5wt%-Pt/g-C₃N₄(665?mol g^-1h^-1),due to the shadow affect of light and hinder reactants to receive the active sites.This work uses the nickel-phosphorus?Ni-P?as cocatalyst to decorate g-C₃N₄?g-C₃N₄/Ni-P?for photocatalytic water splitting to H₂ generation.The g-C3N4/Ni-P composite is prepared through two steps,first step is thermal decomposition of urea to produce g-C₃N₄ and the second step is electroless plating to coast Ni-P on the g-C3N4 surface,resulting in the noticeable increase of the photocatalytic activity of g-C₃N₄.Among these as-prepared samples reported in this work,the highest photocatalytic activity is detected at 3 wt%?g-C₃N₄/Ni-P-3%?,in which H₂ production rate is 1051?mol g^-1h^-1.However,higher than 3 wt%Pt modification the g-C₃N₄ generates only 841?mol g^-1h^-1 of H₂,and almost no generation of H₂ by pure g-C₃N₄ has been determined.Based on photoluminescence and photocurrent measurements,a photocatalytic mechanism for pure g-C₃N₄ and g-C₃N₄/Ni-P-3%has been suggested,that is,the loading of Ni-P NPs accelerates the separation of photogenerated e^--h⁺pairs and relaying photogenrated e^-via Ni-P particles to react with H₂O,and thus improves photocatalytic performance of g-C₃N₄for water splitting into H₂ generation.