Synthesis And Catalytic Activity Of Graphdiyne-based Composites

Energy crunch and environment contamination are two major problems facing human beings nowadays.Developing highly active catalysts is urgent to tackle these problems.Although noble metal-based catalysts have attractive catalytic performance,the scarcity of resources,excessive price and unfavorable stability promote the use of substitutional catalysts（including transition metal and metal-free,etc.）.In recent years,carbon materials,such as carbon nanotubes,graphene and graphdiyne,have shown excellent advantages in stability,durability and price.Graphdiyne（GDY）,as a new-type category of carbon materials,is consisted of the hybrid sp²-and sp-carbons.The highπ-conjugate system and18-carbon triangle ring structure endow it with high specific surface area,evenly distributed porosity,exorbitant stability and superior charge transference rate.In this paper,GDY-based composites were synthesized by the hydrothermal method and in-situ growth method,their applications in electrocatalysis,enzyme catalysis and the degradation of organic compounds were explored.The content of this paper was mainly divided into three parts:In the first part,the NiFe-LDH/GDY/G composite was synthesized by hydrothermal method.The electrocatalytic oxygen evolution reaction（OER）of NiFe-LDH/GDY/G composite was investigated in an alkaline solution(1 mol L^-1 KOH).The results showed that the unique structure of GDY/G significantly enhanced the OER activity of NiFe-LDH.The NiFe-LDH/GDY/G composite required an overpotential of 251 mV when the current density was 10 m A cm^-2 due to its large electrochemical active surface area and excellent charge transfer ability,which was obviously better than that of GDY/G,NiFe-LDH,NiFe-LDH/G and NiFe-LDH/GDY,and performed good stability.In the second part,graphdiyne encapusulated copper sulfide（CuS@GDY）composite was prepared by in-situ growth of graphdiyne on hollow copper sulfide surface,to investigate the peroxidase-like activity and the degradation of methylene blue（MB）.CuS@GDY composite could catalyze the decomposition of hydrogen peroxide（H₂O₂）to produce free radicals,and then oxidize 3,3’,5,5’-tetramethylbenzidine（TMB）to the blue product（ox TMB）.Based on the peroxidase-like activity,the CuS@GDY/H₂O₂ system was constructed to degrade methylene blue.The results showed that the peroxidase-like activity and degradation performance of CuS@GDY composite were superior to that of CuS and GDY,owing to the synergistic effect of CuS and GDY.In the third part,the CuS@GDY composite was synthesized by the above method and its degradation of bisphenol A（BPA）by potassium persulfate（PMS）was investigated.The results showed that 90.9%(20 mg L^-1)BPA or 97.3%(10 mg L^-1)BPA was degraded by 5mg CuS@GDY and 0.5 mmol L^-1 PMS within 60 min.Active species produced by the CuS@GDY/PMS system played an important role in the degradation process.