Study On The Preparation And Photocatalytic Activity Under Visible Light Irradiation Of Ag₂NCN Composite Materials

Energy crisis and increasing environmental pollution are two of the greatest problems for human being.Within this contest,photocatalysis has attracted intense attention because of its advantage in the complete mineralization of organic pollutants and hydrogen generation through water splitting.Some conductors with wide band gap was mostly studied,however,which application was been restricted due to low solar utilization.Recently,developing new kind of conductor with good visible response is still the research pot.Silver cyanamide as a new material was reported seldom,although theoretically,which has good visible light response and photocatalytic activity.Rectangular Ag2NCN with monoclinic crystalline was synthesized through chemical precipitation using silver nitrate and cyanamide as precursor.The photocatalytic results showed that the Ag2NCN had good photocatalytic activity in the degradation of organic dyes under visible light irradiation.The pH values affected the photocatalytic reaction,and photocatalytic efficiency increased as the pH values decreased.The photocatalytic mechanism of the Ag2NCN particles were discussed too.The TiO2/Ag2NCN composite catalysts were fabricated through the precipitation of silver salt and cyanamide in the presence of TiO2 nanoparticles.X-ray diffraction(XRD),scanning electron microscopy(SEM),FT-IR,UV-Vis spectra and elecrochemical measurement were used to character the composites.The results showed that the heterojunction structure was obtained by depositing the TiO2 nanoparticles on the surface of Ag2NCN.The energy band structure of composite particles demonstrated that the presence of TiO2 promoted the separation of photogenerated electron and hole,and as a result,improved the photocatalytic activity.The hydrogen generation tests present that the photochemical reduction was occurred and the photocatalytic efficiency was improved.The TiO2/Ag2NCN composite catalysts showed good photocatalytic stability.The Ag/Ag2NCN composite catalysts were prepared by the surface chemical reduction of Ag2NCN particles.X-ray diffraction(XRD),scanning electron microscopy(SEM),FT-IR,UV-Vis spectra and elecrochemical measurement were used to character the composites.The results showed that the Ag nanoparticles were formed on the surface of Ag2NCN,and the surface plasmon effect of Ag could enhance the visible light response of Ag/Ag2NCN composite catalysts.The UV-Vis absorption of Ag/Ag2NCN was blue-shift,which implied that the band gap of Ag/Ag2NCN narrowed.In the photocatalytic degradation of Acid blue 1,the Ag/Ag2NCN composite particles showed enhanced photocatalytic activity.