Expanding the optical absorption range of photocatalysts is still a key endeavor in graphitic carbon nitride(g-C_(3)N_(4))studies.Here,we report on a novel thiophene group extending the optical property,which is assig...Expanding the optical absorption range of photocatalysts is still a key endeavor in graphitic carbon nitride(g-C_(3)N_(4))studies.Here,we report on a novel thiophene group extending the optical property,which is assigned to n-π^(*)electronic transitions involving the two lone pairs on sulfur(TLPS).The as-prepared samples,denoted as CN-ThAx(where x indicates the amount of ThA added,mg),showed an additional absorption above 500 nm as compared to pristine g-C_(3)N_(4).Further,the thiophene group enhanced charge carrier separation to suppress e‒/h+pair recombination.The experimental results suggest that the thiophene group can obstruct the polymerization of melem to generate a large plane,thus exposing the lone electron pairs on the sulfur.The photocatalytic activity was evaluated in the decomposition of bisphenol A and H2 evolution.Compared with g-C_(3)N_(4),the optimized CN-ThA_(30) sample led to a 6.6-and 2-fold enhancement of the degradation and H2 generation rates,respectively.The CN-ThA_(30) sample allowed for synchronous H2 production and BPA decomposition.展开更多
A ratiometric fluorescent probe for hypoxanthine(Hx)detection was established based on the mimic enzyme and fluorescence characteristics of cobalt-doped graphite-phase carbon nitride(Co doped g-C_(3)N_(4)).In addition...A ratiometric fluorescent probe for hypoxanthine(Hx)detection was established based on the mimic enzyme and fluorescence characteristics of cobalt-doped graphite-phase carbon nitride(Co doped g-C_(3)N_(4)).In addition to emitting strong fluorescence,the peroxidase activity of Co doped g-C_(3)N_(4)can catalyze the reaction of O-phenylenediamine and H_(2)O_(2)to produce diallyl phthalate which can emit yellow fluorescence at 570 nm.Through the decomposition of Hx by xanthine oxidase,Hx can be indirectly detected by the generating hydrogen peroxide based on the measurement of fluorescent ratio I(F_(570)/F_(370)).The linear range was 1.7-272.2 mg/kg(R^(2)=0.997),and the detection limit was 1.52 mg/kg(3σ/K,n=9).The established method was applied to Hx detection in bass,grass carp,and shrimp,and the data were verified by HPLC.The result shows that the established probe is sensitive,accurate,and reliable,and can be used for Hx detection in aquatic products.展开更多
The rational fabrication of an efficient heterojunction is critical to the enhancement of photocatalytic hydrogen(H_(2)) evolution performance.Herein,a new-fashioned graphitic-carbon nitride(g-C_(3) N_(4)) based isoty...The rational fabrication of an efficient heterojunction is critical to the enhancement of photocatalytic hydrogen(H_(2)) evolution performance.Herein,a new-fashioned graphitic-carbon nitride(g-C_(3) N_(4)) based isotype step-scheme(S-scheme) heterojunction composed of sulfur-doped and sulfur-free active sites is developed by liquid sulfur-mediation of exfoliated g-C_(3) N_(4).Particularly,the liquid sulfur not only contributes to the full contact between sulfur species and exfoliated g-C_(3) N_(4),but also creates sulfur-doping and abundant pores,since self-gas foaming effect of sulfur vapor.Moreover,the S-doped and S-free active sites located in the structural unit of C_(3) N_(4) jointly construct a typical sulfur-doped g-C_(3) N_(4)/g-C_(3) N_(4) isotype step-scheme heterojunction,which endows highly efficient photocatalytic reaction process.Therefore,the optimal sample possesses remarkable photocatalytic H_(2) evolution activity(5548.1 μmol g^(-1) h^(-1)) and robust durability.Most importantly,the investigation will open up a new path for the exploration of other carbon-based isotype S-scheme heterojunctions.展开更多
Nanomaterials integrated surface acoustic wave(SAW)gas sensing technology has emerged as a promising candidate for realtime toxic gas sensing applications for environmental and human health safety.However,the developm...Nanomaterials integrated surface acoustic wave(SAW)gas sensing technology has emerged as a promising candidate for realtime toxic gas sensing applications for environmental and human health safety.However,the development of novel chemical interface based on two-dimensional(2D)sensing materials for SAW sensors for the rapid and sensitive detection of NH_(3)gas at room temperature(RT)still remains challenging.Herein,we report a highly selective RT NH_(3)gas sensor based on sulfur-doped graphitic carbon nitride quantum dots(S@g-C_(3)N_(4)QD)coated langasite(LGS)SAW sensor with enhanced sensitivity and recovery rate under ultraviolet(UV)illumination.Fascinatingly,the sensitivity of the S@g-C_(3)N_(4)QD/LGS SAW sensor to NH_(3)(500 ppb)at RT is dramatically enhanced by~4.5-fold with a low detection limit(~85 ppb),high selectivity,excellent reproducibility,fast response/recovery time(70 s/79 s)under UV activation(365 nm)as compared to dark condition.Additionally,the proposed sensor exhibited augmented NH_(3)detection capability across the broad range of relative humidity(20%–80%).Such remarkable gas sensing performances of the as-prepared sensor to NH_(3)are attributed to the high surface area,enhanced functional groups,sulfur defects,UV photogenerated charge carriers,facile charge transfer in the S@g-C_(3)N_(4)QD sensing layer,which further helps to improve the gas molecules adsorption that causes the increase in conductivity,resulting in larger frequency responses.The gas sensing mechanism of S@g-C_(3)N_(4)QD/LGS SAW sensor is ascribed to the enhanced electroacoustic effect,which is supported by the correlation of resistive type and COMSOL Multiphysics simulation studies.We envisage that the present work paves a promising strategy to develop the next generation 2D g-C_(3)N_(4)based high responsive RT SAW gas sensors.展开更多
Developing environmentally friendly methods to produce hydrogen peroxide(H_(2)O_(2))has received increasing attention.Photocatalysis has been proved to be a sustainable technology for H_(2)O_(2)production.Herein,the n...Developing environmentally friendly methods to produce hydrogen peroxide(H_(2)O_(2))has received increasing attention.Photocatalysis has been proved to be a sustainable technology for H_(2)O_(2)production.Herein,the novel non-metal elements(B,P,and S)doped g-C_(3)N_(4)tubes(B-CNT,P-CNT,and S-CNT)photocatalysts were obtained via a hydrothermal synthesis followed by thermal polymerization.By adjusting the precursor,the yield of g-C_(3)N_(4)tubes(CNT)materials has been greatly improved.The as-prepared B-CNT,P-CNT,and S-CNT photocatalysts show an enhanced photocatalytic H_(2)O_(2)production with the formation rate constants values of 42.31μM min^(-1),24.95μM min^(-1),and 24.22μM min^(-1),respectively,which is higher than that of bulk CN(16.40μM min^(-1)).The doped B,P,S elements significantly enhanced the photocatalytic activity by adjusting their electronic structures and promoting the separation of electronhole carriers.The results have shown great potential for the practical application of CNT photocatalysts.展开更多
In this paper,sulfur doped g-C_(3)N_(4)(S-g-C_(3)N_(4))was successfully prepared at 500℃ for 3 h via a modified molten salt method using dicyandiamide as the main raw material,trithiocyanuric acid as the sulfur sourc...In this paper,sulfur doped g-C_(3)N_(4)(S-g-C_(3)N_(4))was successfully prepared at 500℃ for 3 h via a modified molten salt method using dicyandiamide as the main raw material,trithiocyanuric acid as the sulfur source and LiBreKCl as the reaction medium.The as-prepared SeCN5.0% sample(the mass ratio of trithiocyanuric acid to dicyandiamide was 5.0%)composed of irregular flakes showed a band gap of 1.83 eV,which was narrower than that(2.55 eV)of pristine g-C_(3)N_(4).The SeCN5.0% sample also exhibited an outstanding absorption capacity of visible light.Moreover,the photodegradation rate toward methylene blue and tetracycline were respectively 10 and 20 times as high as that of bulk g-C_(3)N_(4) prepared by conventional heating methods,confirming its superior photocatalytic performance.These results can be attributed to that the replacement of lattice nitrogen with sulfur atom tuned the electronic structure of g-C_(3)N_(4),improved the absorption of visible light,optimized the separation of photogenerated electron-hole pairs,and consequently enhanced the photocatalytic activity of g-C_(3)N_(4).Moreover,the trapping experiments implied that hole(ht)and superoxide radical($O2)were the main active species in the process of photodegradation.展开更多
In this study,waste pigeon guano(PG)was re-utilized as an ideal biomass adulterant to improve the photocatalytic activity of the pristine graphitic carbon nitride(g-C_(3)N_(4)).Waste PG and melamine were employed as p...In this study,waste pigeon guano(PG)was re-utilized as an ideal biomass adulterant to improve the photocatalytic activity of the pristine graphitic carbon nitride(g-C_(3)N_(4)).Waste PG and melamine were employed as precursors to fabricate a novel porous multielement-doped g-C_(3)N_(4)(CN-PG-S)nanosheets photocatalyst via in situ thermal polycondensation coupled with thermal exfoliation strategy.The CN-PG-S owned abundant uniformly porous structures,superior conductivity,and excellent photocatalytic abilities,resulting in highly-efficient H_(2)-production(1950μmol g^(–1) h^(–1))and Cr(Ⅵ)reduction(99.1%)un-der visible light,which increased by 22.9-folds and 5.3-folds more than that of pristine g-C_(3)N_(4).The non-metallic(P,S,and O)and metallic elements in CN-PG-S played a crucial role in expanding the visible-light absorption range and promoting the separation-migration of photogenerated electron-hole pairs.And the uniformly porous nanosheet structure of CN-PG-S shortens the diffusion paths of photogenerated carri-ers and exposes more active sites for photocatalytic reactions.This study proposed an eco-friendly re-sources integration strategy of waste PG to prepare excellent CN-PG-S photocatalysts for highly-efficient H_(2)-production and Cr(VI)reduction.展开更多
As one of the 2D transition metal sulfides,1T phase MoS_(2) nanosheets(NSs)have been studied because of their distinguished conductivity and suitable electronic structure.Nevertheless,the active sites are limited to a...As one of the 2D transition metal sulfides,1T phase MoS_(2) nanosheets(NSs)have been studied because of their distinguished conductivity and suitable electronic structure.Nevertheless,the active sites are limited to a small number of edge sites only,while the basal plane is catalytically inert.Herein,we report that boron(B)doped 1T phase MoS_(2) NSs can replace precious metals as a co-catalyst to assist in photocatalytic H_(2) production of 2D layered g-C_(3)N_(4) nanosheets(g-C_(3)N_(4) NSs).The H_(2) evolution rate of prepared B-MoS_(2)@g-C_(3)N_(4) composites with 15 wt%B-MoS_(2)(B-MoS_(2)@g-C_(3)N_(4)–15,1612.75μmol h^(−1) g^(−1))is 52.33 times of pure g-C_(3)N_(4) NSs(30.82μmol h^(−1) g^(−1)).Furthermore,the apparent quantum efficiency(AQE)of B-MoS_(2)@g-C_(3)N_(4)–15 composites under the light atλ=370 nm is calculated and reaches 5.54%.The excellent photocatalytic performance of B-MoS_(2)@g-C_(3)N_(4)–15 composites is attributed to the B ions doping inducing the distortion of 1T phase MoS_(2) crystal,which can activate more base planes to offer more active sites for H_(2) evolution reaction(HER).This work of B-MoS_(2)@g-C_(3)N_(4) composites offers experience in the progress of effective and low-price photocatalysts for HER.展开更多
Photocatalysis is an efective means to solve the greenhouse efect caused by the large amount of carbon dioxide(CO_(2))emissions from fossil fuel consumption.Graphitic carbon nitride(g-C_(3)N_(4))has the advantages of ...Photocatalysis is an efective means to solve the greenhouse efect caused by the large amount of carbon dioxide(CO_(2))emissions from fossil fuel consumption.Graphitic carbon nitride(g-C_(3)N_(4))has the advantages of suitable band gap,easy preparation,low price,and good stability,making it a promising semiconductor photocatalyst.However,bulk g-C3N4 also has disadvantages such as low gas adsorption,low photocatalytic efciency,narrow spectral response,and easy recombination of electron–hole pairs.The modifcation method based on g-C_(3)N_(4) photocatalyst helps to improve the above-mentioned problems.This review summarizes the research progress in recent years from four aspects:morphology adjustment,co-catalysts,heterostructures and doping.Each aspect includes the pros and cons of diferent improvement methods,the comparison of theoretical calculations and experimental results,the application of diferent characterization methods,and the detailed listing of product yield and selectivity.Prior to this,there was an explanation of the basic theory of semiconductor photocatalytic CO_(2) reduction.Finally,the future challenges and development prospects are also briefy prospected.展开更多
Durable and inexpensive graphitic carbon nitride(g-C_(3)N_(4))demonstrates great potential for achieving efficient photocatalytic hydrogen evolution reduction(HER).To further improve its activity,g-C_(3)N_(4)was subje...Durable and inexpensive graphitic carbon nitride(g-C_(3)N_(4))demonstrates great potential for achieving efficient photocatalytic hydrogen evolution reduction(HER).To further improve its activity,g-C_(3)N_(4)was subjected to atomic-level structural engineering by doping with transition metals(M=Fe,Co,or Ni),which simultaneously induced the formation of metal-N active sites in the g-C_(3)N_(4)framework and modulated the bandgap of g-C_(3)N_(4).Experiments and density functional theory calculations further verified that the as-formed metal-N bonds in M-doped g-C_(3)N_(4)acted as an"electron transfer bridge",where the migration of photo-generated electrons along the bridge enhanced the efficiency of separation of the photogenerated charges,and the optimized bandgap of g-C_(3)N_(4)afforded stronger reduction ability and wider light absorption.As a result,doping with either Fe,Co,or Ni had a positive effect on the HER activity,where Co-doped g-C_(3)N_(4)exhibited the highest performance.The findings illustrate that this atomic-level structural engineering could efficiently improve the HER activity and inspire the design of powerful photocatalysts.展开更多
Defect construction and heteroatom doping are effective strategies for improving photocatalytic activity of carbon nitride(g-C_(3)N_(4)).In this work,N defects were successfully prepared via cold plasma.High-energy el...Defect construction and heteroatom doping are effective strategies for improving photocatalytic activity of carbon nitride(g-C_(3)N_(4)).In this work,N defects were successfully prepared via cold plasma.High-energy electrons generated by plasma can produce N defects and embed sulfur atoms into g-C_(3)N_(4).The N defects obviously promoted photocatalytic degradation performance that was 7.5 times higher than that of pure g-C_(3)N_(4).The concentration of N defects can be tuned by different power and time of plasma.With the increase in N defects,the photocatalytic activity showed a volcanic trend.The g-C_(3)N_(4)with moderate concentration of N defects exhibited the highest photocatalytic activity.S-doped g-C_(3)N_(4)exhibited 11.25 times higher photocatalytic activity than pure g-C_(3)N_(4).It provided extra active sites for photocatalytic reaction and improved stability of N defects.The N vacancy-enriched and S-doped g-C_(3)N_(4)are beneficial for widening absorption edge and improving the separation efficiency of electron and holes.展开更多
文摘Expanding the optical absorption range of photocatalysts is still a key endeavor in graphitic carbon nitride(g-C_(3)N_(4))studies.Here,we report on a novel thiophene group extending the optical property,which is assigned to n-π^(*)electronic transitions involving the two lone pairs on sulfur(TLPS).The as-prepared samples,denoted as CN-ThAx(where x indicates the amount of ThA added,mg),showed an additional absorption above 500 nm as compared to pristine g-C_(3)N_(4).Further,the thiophene group enhanced charge carrier separation to suppress e‒/h+pair recombination.The experimental results suggest that the thiophene group can obstruct the polymerization of melem to generate a large plane,thus exposing the lone electron pairs on the sulfur.The photocatalytic activity was evaluated in the decomposition of bisphenol A and H2 evolution.Compared with g-C_(3)N_(4),the optimized CN-ThA_(30) sample led to a 6.6-and 2-fold enhancement of the degradation and H2 generation rates,respectively.The CN-ThA_(30) sample allowed for synchronous H2 production and BPA decomposition.
基金supported by the National Natural Science Foundation of China(21804050)the National Key R and D Program of China(2018YFD0901003)+2 种基金the Science and Technology Planning Project of Xiamen,China(3502Z20183031)the Fujian Provincial Fund Project(2018J01432)the Xiamen Science and Technology Planning Project,China(3502Z20183031)。
文摘A ratiometric fluorescent probe for hypoxanthine(Hx)detection was established based on the mimic enzyme and fluorescence characteristics of cobalt-doped graphite-phase carbon nitride(Co doped g-C_(3)N_(4)).In addition to emitting strong fluorescence,the peroxidase activity of Co doped g-C_(3)N_(4)can catalyze the reaction of O-phenylenediamine and H_(2)O_(2)to produce diallyl phthalate which can emit yellow fluorescence at 570 nm.Through the decomposition of Hx by xanthine oxidase,Hx can be indirectly detected by the generating hydrogen peroxide based on the measurement of fluorescent ratio I(F_(570)/F_(370)).The linear range was 1.7-272.2 mg/kg(R^(2)=0.997),and the detection limit was 1.52 mg/kg(3σ/K,n=9).The established method was applied to Hx detection in bass,grass carp,and shrimp,and the data were verified by HPLC.The result shows that the established probe is sensitive,accurate,and reliable,and can be used for Hx detection in aquatic products.
基金supported by the National Natural Science Foundation of China (Nos.62004143 and 21975084)the Central Government Guided Local Science and Technology Development Special Fund Project (No.2020ZYYD033)+5 种基金the Natural Science Foundation of Hubei Province (No.2021CFB133)the Opening Fund of Key Laboratory of Rare Mineral,Ministry of Natural Resources(No.KLRM-KF 202005)the Opening Fund of Key Laboratory for Green Chemical Process of Ministry of Education of Wuhan Institute of Technology (No.GCP202101)the Open Research Fund of Key Laboratory of Material Chemistry for Energy Conversion and Storage (HUST),Ministry of Education (No.2021JYBKF05)the Innovation Project of Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education (No.LCX2021003)the 12^(th) Graduate Education Innovation Fund of Wuhan Institute of Technology (No.CX2020341)。
文摘The rational fabrication of an efficient heterojunction is critical to the enhancement of photocatalytic hydrogen(H_(2)) evolution performance.Herein,a new-fashioned graphitic-carbon nitride(g-C_(3) N_(4)) based isotype step-scheme(S-scheme) heterojunction composed of sulfur-doped and sulfur-free active sites is developed by liquid sulfur-mediation of exfoliated g-C_(3) N_(4).Particularly,the liquid sulfur not only contributes to the full contact between sulfur species and exfoliated g-C_(3) N_(4),but also creates sulfur-doping and abundant pores,since self-gas foaming effect of sulfur vapor.Moreover,the S-doped and S-free active sites located in the structural unit of C_(3) N_(4) jointly construct a typical sulfur-doped g-C_(3) N_(4)/g-C_(3) N_(4) isotype step-scheme heterojunction,which endows highly efficient photocatalytic reaction process.Therefore,the optimal sample possesses remarkable photocatalytic H_(2) evolution activity(5548.1 μmol g^(-1) h^(-1)) and robust durability.Most importantly,the investigation will open up a new path for the exploration of other carbon-based isotype S-scheme heterojunctions.
基金the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2020R1A2C2013385)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.NRF-2020R1A6A1A03047771)Korea Institute of Planning and Evaluation for Technology in Food,Agriculture and Forestry(IPET),Korea Smart Farm Research and Development Foundation(KosFarm)through Smart Farm Innovation Technology Development Program,funded by Ministry of Agriculture,Food,and Rural Affairs(MAFRA)and Ministry of Science and ICT(MSIT),Rural Development Administration(RDA)(No.421029-4).
文摘Nanomaterials integrated surface acoustic wave(SAW)gas sensing technology has emerged as a promising candidate for realtime toxic gas sensing applications for environmental and human health safety.However,the development of novel chemical interface based on two-dimensional(2D)sensing materials for SAW sensors for the rapid and sensitive detection of NH_(3)gas at room temperature(RT)still remains challenging.Herein,we report a highly selective RT NH_(3)gas sensor based on sulfur-doped graphitic carbon nitride quantum dots(S@g-C_(3)N_(4)QD)coated langasite(LGS)SAW sensor with enhanced sensitivity and recovery rate under ultraviolet(UV)illumination.Fascinatingly,the sensitivity of the S@g-C_(3)N_(4)QD/LGS SAW sensor to NH_(3)(500 ppb)at RT is dramatically enhanced by~4.5-fold with a low detection limit(~85 ppb),high selectivity,excellent reproducibility,fast response/recovery time(70 s/79 s)under UV activation(365 nm)as compared to dark condition.Additionally,the proposed sensor exhibited augmented NH_(3)detection capability across the broad range of relative humidity(20%–80%).Such remarkable gas sensing performances of the as-prepared sensor to NH_(3)are attributed to the high surface area,enhanced functional groups,sulfur defects,UV photogenerated charge carriers,facile charge transfer in the S@g-C_(3)N_(4)QD sensing layer,which further helps to improve the gas molecules adsorption that causes the increase in conductivity,resulting in larger frequency responses.The gas sensing mechanism of S@g-C_(3)N_(4)QD/LGS SAW sensor is ascribed to the enhanced electroacoustic effect,which is supported by the correlation of resistive type and COMSOL Multiphysics simulation studies.We envisage that the present work paves a promising strategy to develop the next generation 2D g-C_(3)N_(4)based high responsive RT SAW gas sensors.
基金financially supported by the Jiangsu Key Science and Technology Project(No.BE2019108)the National Natural Science Foundation of China(No.21173041)the Opening Project of Jiangsu Key Laboratory of Advanced Metallic Materials,China。
文摘Developing environmentally friendly methods to produce hydrogen peroxide(H_(2)O_(2))has received increasing attention.Photocatalysis has been proved to be a sustainable technology for H_(2)O_(2)production.Herein,the novel non-metal elements(B,P,and S)doped g-C_(3)N_(4)tubes(B-CNT,P-CNT,and S-CNT)photocatalysts were obtained via a hydrothermal synthesis followed by thermal polymerization.By adjusting the precursor,the yield of g-C_(3)N_(4)tubes(CNT)materials has been greatly improved.The as-prepared B-CNT,P-CNT,and S-CNT photocatalysts show an enhanced photocatalytic H_(2)O_(2)production with the formation rate constants values of 42.31μM min^(-1),24.95μM min^(-1),and 24.22μM min^(-1),respectively,which is higher than that of bulk CN(16.40μM min^(-1)).The doped B,P,S elements significantly enhanced the photocatalytic activity by adjusting their electronic structures and promoting the separation of electronhole carriers.The results have shown great potential for the practical application of CNT photocatalysts.
基金This workwas financially supported by National Natural Science Foundation of China(Grant No.51872210 and 52072274)Program for Innovative Teams of Outstanding Young and Middle-aged Researchers in the Higher Education Institutions of Hubei Province(T201602)Key Program of Natural Science Foundation of Hubei Province,China(Grant/Award Number:2017CFA004).
文摘In this paper,sulfur doped g-C_(3)N_(4)(S-g-C_(3)N_(4))was successfully prepared at 500℃ for 3 h via a modified molten salt method using dicyandiamide as the main raw material,trithiocyanuric acid as the sulfur source and LiBreKCl as the reaction medium.The as-prepared SeCN5.0% sample(the mass ratio of trithiocyanuric acid to dicyandiamide was 5.0%)composed of irregular flakes showed a band gap of 1.83 eV,which was narrower than that(2.55 eV)of pristine g-C_(3)N_(4).The SeCN5.0% sample also exhibited an outstanding absorption capacity of visible light.Moreover,the photodegradation rate toward methylene blue and tetracycline were respectively 10 and 20 times as high as that of bulk g-C_(3)N_(4) prepared by conventional heating methods,confirming its superior photocatalytic performance.These results can be attributed to that the replacement of lattice nitrogen with sulfur atom tuned the electronic structure of g-C_(3)N_(4),improved the absorption of visible light,optimized the separation of photogenerated electron-hole pairs,and consequently enhanced the photocatalytic activity of g-C_(3)N_(4).Moreover,the trapping experiments implied that hole(ht)and superoxide radical($O2)were the main active species in the process of photodegradation.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52070171 and 52030003)China Postdoctoral Science Foundation(Grant No.2022M710138).
文摘In this study,waste pigeon guano(PG)was re-utilized as an ideal biomass adulterant to improve the photocatalytic activity of the pristine graphitic carbon nitride(g-C_(3)N_(4)).Waste PG and melamine were employed as precursors to fabricate a novel porous multielement-doped g-C_(3)N_(4)(CN-PG-S)nanosheets photocatalyst via in situ thermal polycondensation coupled with thermal exfoliation strategy.The CN-PG-S owned abundant uniformly porous structures,superior conductivity,and excellent photocatalytic abilities,resulting in highly-efficient H_(2)-production(1950μmol g^(–1) h^(–1))and Cr(Ⅵ)reduction(99.1%)un-der visible light,which increased by 22.9-folds and 5.3-folds more than that of pristine g-C_(3)N_(4).The non-metallic(P,S,and O)and metallic elements in CN-PG-S played a crucial role in expanding the visible-light absorption range and promoting the separation-migration of photogenerated electron-hole pairs.And the uniformly porous nanosheet structure of CN-PG-S shortens the diffusion paths of photogenerated carri-ers and exposes more active sites for photocatalytic reactions.This study proposed an eco-friendly re-sources integration strategy of waste PG to prepare excellent CN-PG-S photocatalysts for highly-efficient H_(2)-production and Cr(VI)reduction.
基金fundings from the National Natural Science Foundation of China(No.51872173)Taishan Scholars Program of Shandong Province(No.tsqn201812068)+1 种基金Natural Science Foundation of Shandong Province(No.ZR2022JQ21)Higher School Youth Innovation Team of Shandong Province(No.2019KJA013).
文摘As one of the 2D transition metal sulfides,1T phase MoS_(2) nanosheets(NSs)have been studied because of their distinguished conductivity and suitable electronic structure.Nevertheless,the active sites are limited to a small number of edge sites only,while the basal plane is catalytically inert.Herein,we report that boron(B)doped 1T phase MoS_(2) NSs can replace precious metals as a co-catalyst to assist in photocatalytic H_(2) production of 2D layered g-C_(3)N_(4) nanosheets(g-C_(3)N_(4) NSs).The H_(2) evolution rate of prepared B-MoS_(2)@g-C_(3)N_(4) composites with 15 wt%B-MoS_(2)(B-MoS_(2)@g-C_(3)N_(4)–15,1612.75μmol h^(−1) g^(−1))is 52.33 times of pure g-C_(3)N_(4) NSs(30.82μmol h^(−1) g^(−1)).Furthermore,the apparent quantum efficiency(AQE)of B-MoS_(2)@g-C_(3)N_(4)–15 composites under the light atλ=370 nm is calculated and reaches 5.54%.The excellent photocatalytic performance of B-MoS_(2)@g-C_(3)N_(4)–15 composites is attributed to the B ions doping inducing the distortion of 1T phase MoS_(2) crystal,which can activate more base planes to offer more active sites for H_(2) evolution reaction(HER).This work of B-MoS_(2)@g-C_(3)N_(4) composites offers experience in the progress of effective and low-price photocatalysts for HER.
基金This research was supported by Key Program for International S&T Cooperation Program of China(2017YFE0113000)the National Natural Science Foundation of China(51971133,51801121,51902200,and 52072241)+2 种基金the Shanghai Science and Technology Committee(18JC1410500,19JC1410400,19ZR1425100,and 18ZR1420900)the National Key Research and Development Program(YS2017YFGH000385)State Key Laboratory for Modifcation of Chemical Fibers and Polymer Materials,Donghua University.
文摘Photocatalysis is an efective means to solve the greenhouse efect caused by the large amount of carbon dioxide(CO_(2))emissions from fossil fuel consumption.Graphitic carbon nitride(g-C_(3)N_(4))has the advantages of suitable band gap,easy preparation,low price,and good stability,making it a promising semiconductor photocatalyst.However,bulk g-C3N4 also has disadvantages such as low gas adsorption,low photocatalytic efciency,narrow spectral response,and easy recombination of electron–hole pairs.The modifcation method based on g-C_(3)N_(4) photocatalyst helps to improve the above-mentioned problems.This review summarizes the research progress in recent years from four aspects:morphology adjustment,co-catalysts,heterostructures and doping.Each aspect includes the pros and cons of diferent improvement methods,the comparison of theoretical calculations and experimental results,the application of diferent characterization methods,and the detailed listing of product yield and selectivity.Prior to this,there was an explanation of the basic theory of semiconductor photocatalytic CO_(2) reduction.Finally,the future challenges and development prospects are also briefy prospected.
文摘Durable and inexpensive graphitic carbon nitride(g-C_(3)N_(4))demonstrates great potential for achieving efficient photocatalytic hydrogen evolution reduction(HER).To further improve its activity,g-C_(3)N_(4)was subjected to atomic-level structural engineering by doping with transition metals(M=Fe,Co,or Ni),which simultaneously induced the formation of metal-N active sites in the g-C_(3)N_(4)framework and modulated the bandgap of g-C_(3)N_(4).Experiments and density functional theory calculations further verified that the as-formed metal-N bonds in M-doped g-C_(3)N_(4)acted as an"electron transfer bridge",where the migration of photo-generated electrons along the bridge enhanced the efficiency of separation of the photogenerated charges,and the optimized bandgap of g-C_(3)N_(4)afforded stronger reduction ability and wider light absorption.As a result,doping with either Fe,Co,or Ni had a positive effect on the HER activity,where Co-doped g-C_(3)N_(4)exhibited the highest performance.The findings illustrate that this atomic-level structural engineering could efficiently improve the HER activity and inspire the design of powerful photocatalysts.
基金supported by the National Natural Science Foundation of China(Grant Nos.21878214 and 21938009).
文摘Defect construction and heteroatom doping are effective strategies for improving photocatalytic activity of carbon nitride(g-C_(3)N_(4)).In this work,N defects were successfully prepared via cold plasma.High-energy electrons generated by plasma can produce N defects and embed sulfur atoms into g-C_(3)N_(4).The N defects obviously promoted photocatalytic degradation performance that was 7.5 times higher than that of pure g-C_(3)N_(4).The concentration of N defects can be tuned by different power and time of plasma.With the increase in N defects,the photocatalytic activity showed a volcanic trend.The g-C_(3)N_(4)with moderate concentration of N defects exhibited the highest photocatalytic activity.S-doped g-C_(3)N_(4)exhibited 11.25 times higher photocatalytic activity than pure g-C_(3)N_(4).It provided extra active sites for photocatalytic reaction and improved stability of N defects.The N vacancy-enriched and S-doped g-C_(3)N_(4)are beneficial for widening absorption edge and improving the separation efficiency of electron and holes.
