Rational modification by functional groups was regarded as one of efficient methods to improve the photocatalytic performance of graphitic carbon nitride(g-C3 N4).Herein,g-C3 N4 with yellow(Y-GCN)and brown(C-GCN)were ...Rational modification by functional groups was regarded as one of efficient methods to improve the photocatalytic performance of graphitic carbon nitride(g-C3 N4).Herein,g-C3 N4 with yellow(Y-GCN)and brown(C-GCN)were prepared by using the fresh urea and the urea kept for five years,respectively,for the first time.Experimental results show that the H2 production rate of the C-GCN is 39.06μmol/h,which is about 5 times of the Y-GCN.Meantime,in terms of apparent quantum efficiency(AQ.E)at 420 nm,C-GCN has a value of 6.3%and nearly 7.3 times higher than that of Y-GCN(0.86%).The results of XRD,IR,DRS,and NMR show,different from Y-GCN,a new kind of functional group of—N=CH—was firstly in-situ introduced into the C-GCN,resulting in good visible light absorption,and then markedly improving the photocatalytic performance.DFT calculation also confirms the effect of the—N=CH—group band structure of g-C3N4.Furthermore,XPS results demonstrate that the existence of—N=CH—groups in C-GCN results in tight interaction between C-GCN and Pt nanoparticles,and then improves the charge separation and photocatalytic performance.The present work demonstrates a good example of"defect engineering"to modify the intrinsic molecular structure of g-C3N4 and provides a new avenue to enhance the photocatalytic activity of g-C3N4 via facile and environmental-friendly method.展开更多
Owing to the exorbitant overpotential and serious carrier recombination of graphitic carbon nitride(gC_(3)N_(4)),noble metal(NM)is usually served as the H_(2)evolution co-catalyst.Although the NM(such as Pt)nanopartic...Owing to the exorbitant overpotential and serious carrier recombination of graphitic carbon nitride(gC_(3)N_(4)),noble metal(NM)is usually served as the H_(2)evolution co-catalyst.Although the NM(such as Pt)nanoparticles can reduce the H_(2)evolution overpotential,the weak van der Waals interaction between Pt and g-C_(3)N_(4)makes against the charge transfer.Herein,the solvothermal method is developed to achieve semi-chemical interaction between Pt and g-C_(3)N_(4)nanotube(Pt-CNNT)for fast charge transfer.Moreover,the generated in-plane homojunction of CNNT can accelerate charge separation and restrain recombination.Meanwhile,the metallic Pt is an excellent H_(2)evolution co-catalyst.Photo/electrochemical tests verify that the semi-chemical interaction can improve photogenerated charge separation and transferability of CNNT.As a result,the photocatalytic H_(2)evolution turnover frequency(TOF)of Pt-CNNT under visible light irradiation reaches up to 918 h^(-1),which is one of the highest in the g-C_(3)N_(4)-based photocatalysts.This work provides a new idea to improve the charge transfer for efficient photocatalytic H_(2)evolution.展开更多
基金financial support of the National Natural Science Foundation of China(NSFC,Nos.51622806,51878325,51868050,51378246 and 51720105001)the Natural Science Foundation of Jiangxi Province(Nos.20162BCB22017,20165BCB18008,20171ACB20017,20133ACB21001 and 20171BAB206049)。
文摘Rational modification by functional groups was regarded as one of efficient methods to improve the photocatalytic performance of graphitic carbon nitride(g-C3 N4).Herein,g-C3 N4 with yellow(Y-GCN)and brown(C-GCN)were prepared by using the fresh urea and the urea kept for five years,respectively,for the first time.Experimental results show that the H2 production rate of the C-GCN is 39.06μmol/h,which is about 5 times of the Y-GCN.Meantime,in terms of apparent quantum efficiency(AQ.E)at 420 nm,C-GCN has a value of 6.3%and nearly 7.3 times higher than that of Y-GCN(0.86%).The results of XRD,IR,DRS,and NMR show,different from Y-GCN,a new kind of functional group of—N=CH—was firstly in-situ introduced into the C-GCN,resulting in good visible light absorption,and then markedly improving the photocatalytic performance.DFT calculation also confirms the effect of the—N=CH—group band structure of g-C3N4.Furthermore,XPS results demonstrate that the existence of—N=CH—groups in C-GCN results in tight interaction between C-GCN and Pt nanoparticles,and then improves the charge separation and photocatalytic performance.The present work demonstrates a good example of"defect engineering"to modify the intrinsic molecular structure of g-C3N4 and provides a new avenue to enhance the photocatalytic activity of g-C3N4 via facile and environmental-friendly method.
基金the National Natural Science Foundation of China(Nos.51868050,51938007,51878325,51868052,52100186,52170082,and 52063024)the Natural Science Foundation of Jiangxi Province(Nos.20202BAB213011 and 20181BBG78034)the Scientific Research Foundation of Nanchang Hangkong University(No.EA201902377)。
文摘Owing to the exorbitant overpotential and serious carrier recombination of graphitic carbon nitride(gC_(3)N_(4)),noble metal(NM)is usually served as the H_(2)evolution co-catalyst.Although the NM(such as Pt)nanoparticles can reduce the H_(2)evolution overpotential,the weak van der Waals interaction between Pt and g-C_(3)N_(4)makes against the charge transfer.Herein,the solvothermal method is developed to achieve semi-chemical interaction between Pt and g-C_(3)N_(4)nanotube(Pt-CNNT)for fast charge transfer.Moreover,the generated in-plane homojunction of CNNT can accelerate charge separation and restrain recombination.Meanwhile,the metallic Pt is an excellent H_(2)evolution co-catalyst.Photo/electrochemical tests verify that the semi-chemical interaction can improve photogenerated charge separation and transferability of CNNT.As a result,the photocatalytic H_(2)evolution turnover frequency(TOF)of Pt-CNNT under visible light irradiation reaches up to 918 h^(-1),which is one of the highest in the g-C_(3)N_(4)-based photocatalysts.This work provides a new idea to improve the charge transfer for efficient photocatalytic H_(2)evolution.