Herein,a new type of two-dimensional(2D)/2D Ti_(3)C_(2)/TiO_(2) heterojunction was developed for efficient photocatalytic nitrogen reduction reaction(NRR),in which TiO_(2) nanosheets(TiO_(2) Ns)were designed as the ma...Herein,a new type of two-dimensional(2D)/2D Ti_(3)C_(2)/TiO_(2) heterojunction was developed for efficient photocatalytic nitrogen reduction reaction(NRR),in which TiO_(2) nanosheets(TiO_(2) Ns)were designed as the main catalyst,while Ti_(3)C_(2) MXene served as the co-catalyst.Experimental and theoretical results revealed that Ti_(3)C_(2) MXene introduced electron-rich unsaturated Ti sites,serving as highly active sites for both the adsorption and activation of N_(2) on the Ti_(3)C_(2)/TiO_(2) heterojunction.Furthermore,the 2D/2D Ti_(3)C_(2)/TiO_(2) heterostructure greatly promoted the directional separation and transfer of charge carriers,facilitated by the internal electric field.This structural feature enabled the spatial separation of the N_(2) reduction and H2 O oxidation half-reactions on the distinct surfaces of Ti_(3)C_(2)(001)and TiO_(2)(001),con-sequently reducing the reaction energy barrier for each respective process.The synergistic effects arising from the interface and surface interactions within the heterojunction conspicuously improved the photo-catalytic NRR activity.As a result,the optimized Ti_(3)C_(2)/TiO_(2) heterojunction exhibited a high NH_(3) produc-tion rate of 24.4μmol g−1 h−1 in the absence of sacrificial agents,representing a remarkable 12.8-fold increase compared to individual TiO_(2) Ns.This work provides new insights into rational design of high-performance heterogeneous photocatalysts and offers a deeper understanding of the mechanism under-lying surface active sites in the photocatalytic NRR process.展开更多
Two-dimensional(2D)materials have come to light due to their unique thickness that owns abundant exposed edges with enhanced electrocatalytic properties.2D molybdenum disulfide(MoS_(2))nanosheet has aroused considerab...Two-dimensional(2D)materials have come to light due to their unique thickness that owns abundant exposed edges with enhanced electrocatalytic properties.2D molybdenum disulfide(MoS_(2))nanosheet has aroused considerable attention due to its tunable surface chemistry and high electrochemical sur-face area.Nonetheless,several shortcomings associated with MoS_(2),such as its naturally existing semi-conducting 2H phase,which has limited active sites due to the inert basal plane,restrict its application in water electrocatalysis.Taking into account the benefits of the 1T/2H phase of MoS_(2),as well as the importance of engineering 2D/2D heterojunction interface for boosted electrocatalysis,metallic Ti_(3)C_(2)Tx was integrated with 1T/2H MoS_(2) to develop 2D/2D 1T/2H MoS_(2)/Ti_(3)C_(2)Tx heterostructured nanocompos-ites.Herein,with only 25%of the intercalating agent,1T/2H MoS_(2) with the highest 1T phase content of~82%was successfully synthesized.It was further incorporated with 1 wt%of Ti_(3)C_(2)Tx through a com-bination of ultrasonication and mechanical stirring process.The 1T/2H MoS_(2)(25D)/Ti_(3)C_(2)Tx-1(MTC-1)manifested outstanding electrocatalytic performance with an overpotential and Tafel slope of 280 mV(83.80 mV dec^(-1))and 300 mV(117.2 mV dec^(-1)),for catalyzing acidic and alkaline medium HER,respec-tively.Pivotally,the as-prepared catalysts also illustrated long-term stability for more than 40 h.The coupling method for the 2D nanosheets is crucial to suppress the oxidation of Ti_(3)C_(2)Tx and the restack-ing issue of 2D nanosheets.The superior HER activity is ascribed to the synergistic effect between the heterostructure,enhancing the electronic structure and charge separation capability.The intrinsic prop-erty of the catalyst further confirms by turnover frequency(TOF)calculation.As such,this research paves the way for designing high-efficiency 2D electrocatalysts and sheds light on the further advancement of tunable 2D electrocatalysts for robust water splitting and beyond.展开更多
Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S...Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S_(4) heterostructures with strong hetero-interface interaction and abundant contact were constructed via an impregnation-annealing strategy.Efficient charge transfer from ZnIn_(2)S_(4) to WSe_(2)was evidenced by transient absorption spectroscopy in crafted heterostructures owing to the tight and2D face-to-face contact.As a result,the prepared WSe_(2)/ZnIn_(2)S_(4) heterostructures exhibited boosted photocatalytic performance and a highest hydrogen evolution rate of 3.377 mmol/(g h)was achieved with an apparent quantum yield of 45.7%at 420 nm.The work not only provides new strategies to achieve efficient 2D/2D heterostructures but also paves the way for the development of green hydrogen in the future.展开更多
The design and construction of heterojunction photocatalysts,which possess a staggered energy band structure and appropriate interfacial contact,is an effective way to achieve outstanding photocatalytic performance.In...The design and construction of heterojunction photocatalysts,which possess a staggered energy band structure and appropriate interfacial contact,is an effective way to achieve outstanding photocatalytic performance.In this study,2D/2D BiOBr/g‐C_(3)N_(4)heterojunctions were successfully obtained by a convenient in situ self‐assembly route.Under simulated sunlight irradiation,99%of RhB(10 mg·L–1,100 mL)was efficiently degraded by 1.5‐BiOBr/g‐C_(3)N_(4)within 30 min,which is better than the performance of both BiOBr and g‐C_(3)N_(4),and it has superior stability.In addition,the composite also exhibits enhanced photocatalytic activity for H2 production.The enhanced activity can be attributed to the intimate interface contact,the larger surface area,and the highly efficient separation of photoinduced electron–hole pairs.Based on the experimental results,a novel S‐scheme model was proposed to illuminate the transfer process of charge carriers.This study presents a simple way to develop novel step‐scheme photocatalysts for environmental and related applications.展开更多
A novel 2D/2D Bi_(2)MoO_(6)/g-C_(3)N_(4) step-scheme(S-scheme)composite by loading Au as cocatalyst was successfully fabricated using a photoreduction and hydrothermal route.The obtained Bi_(2)MoO_(6)/g-C_(3)N_(4)/Au ...A novel 2D/2D Bi_(2)MoO_(6)/g-C_(3)N_(4) step-scheme(S-scheme)composite by loading Au as cocatalyst was successfully fabricated using a photoreduction and hydrothermal route.The obtained Bi_(2)MoO_(6)/g-C_(3)N_(4)/Au photocatalysts were characterized by X-ray diffraction(XRD),transmission electron microscope(TEM),X-ray photo-electron spectroscopy(XPS),UV–vis diffuse reflectance spectra(UV–vis),Fourier transform infrared spectroscopy(FTIR),photoluminescence(PL),photocurrent response(I-t),and electrochemical impedance spectroscopy(EIS).The HRTEM images revealed that an intimate interface in composites were formed.The optimum photocatalytic activity of Rhodamine B degradation over Bi_(2)MoO_(6)/g-C_(3)N_(4)/Au was about 9.7 times and 13.1 times as high as those of Bi_(2)MoO_(6) and g-C_(3)N_(4),respectively.The notably improved photocatalytic activity of Bi_(2)MoO_(6)/g-C_(3)N_(4)/Au could be mainly ascribed to the abundant active sites and the enhanced separation efficiency of photogenerated carriers in Bi_(2)MoO_(6)/g-C_(3)N_(4) S-scheme system.Notably,Au nanoparticles could act as a co-catalyst to further promote electron transfer and separation from the conduction band of g-C_(3)N_(4).Additionally,a possible step-scheme photocatalytic reaction mechanism of Rh B degradation over Bi_(2)MoO_(6)/g-C_(3)N_(4)/Au was tentatively proposed.PL and transient photocurrent analysis implied that Bi_(2)MoO_(6)/g-C_(3)N_(4)/Au photocatalysts possessed the lower recombination rate of photogenerated carriers compared with pure Bi_(2) MoO_(6) and g-C_(3)N_(4),respectively.The present work is expected to provide useful information in designing 2D/2D S-scheme heterojunction photocatalysts.展开更多
Reducing CO_(2) to hydrocarbon fuels by solar irradiation provides a feasible channel for mitigating excessive CO_(2) emissions and addressing resource depletion.Nevertheless,severe charge recombi‐nation and the high...Reducing CO_(2) to hydrocarbon fuels by solar irradiation provides a feasible channel for mitigating excessive CO_(2) emissions and addressing resource depletion.Nevertheless,severe charge recombi‐nation and the high energy barrier for CO_(2) photoreduction on the surface of photocatalysts com‐promise the catalytic performance.Herein,a 2D/2D Bi_(2)MoO_(6)/BiOI composite was fabricated to achieve improved CO_(2) photoreduction efficiency.Charge transfer in the composite was facilitated by the van der Waals heterojunction with a large‐area interface.Work function calculation demon‐strated that S‐scheme charge transfer is operative in the composite,and effective charge separation and strong redox capability were revealed by time‐resolved photoluminescence and electron para‐magnetic resonance spectroscopy.Moreover,the intermediates of CO_(2) photoreduction were identi‐fied based on the in situ diffuse reflectance infrared Fourier‐transform spectra.Density functional theory calculations showed that CO_(2) hydrogenation is the rate‐determining step for yielding CH_(4) and CO.Introducing Bi_(2)MoO_(6) into the composite further decreased the energy barrier for CO_(2) photoreduction on BiOI by 0.35 eV.This study verifies the synergistic effect of the S‐scheme heterojunction and van der Waals heterojunction in the 2D/2D composite.展开更多
Two-dimensional(2D)nanomaterials have demonstrated great potential in the field of flexible gas sensing due to their inherent high specific surface areas,unique electronic properties and flexibility property.However,n...Two-dimensional(2D)nanomaterials have demonstrated great potential in the field of flexible gas sensing due to their inherent high specific surface areas,unique electronic properties and flexibility property.However,numerous challenges including sensitivity,selectivity,response time,recovery time,and stability have to be addressed before their practical application in gas detection field.Development of graphene-like 2D/2D nanocomposites as an efficient strategy to achieve high-performance 2D gas sensor has been reported recently.This review aims to discuss the latest advancements in the 2D/2D nanocomposites for gas sensors.We first elaborate the gas-sensing mechanisms and the collective benefits of 2D/2D hybridization as sensor materials.Then,we systematically present the current gas-sensing applications based on different categories of 2D/2D nanocomposites.Finally,we conclude the future prospect of 2D/2D nanocomposites in gas sensing applications.展开更多
Covalent organic frameworks(COFs)have emerged as a kind of rising star materials in photocatalysis.However,their photocatalytic activities are restricted by the high photogenerated electron-hole pairs recombination ra...Covalent organic frameworks(COFs)have emerged as a kind of rising star materials in photocatalysis.However,their photocatalytic activities are restricted by the high photogenerated electron-hole pairs recombination rate.Herein,a novel metal-free 2D/2D van der Waals heterojunction,composed of a two-dimensional(2D)COF with ketoenamine linkage(TpPa-1-COF)and 2D defective hexagonal boron nitride(h-BN),is successfully constructed through in situ solvothermal method.Benefitting from the presence of VDW heterojunction,larger contact area and intimate electronic coupling can be formed between the interface of TpPa-1-COF and defective h-BN,which make contributions to promoting charge car-riers separation.The introduced defects can also endow the h-BN with porous structure,thus providing more reactive sites.Moreover,the TpPa-1-COF will undergo a structural transformation after being integrated with defective h-BN,which can enlarge the gap between the conduction band position of the h-BN and TpPa-1-COF,and suppress electron backflow,corroborated by experimental and density functional theory calculations results.Accordingly,the resulting porous h-BN/TpPa-1-COF metal-free VDW heterojunction displays out-standing solar energy catalytic activity for water splitting without co-catalysts,and the H_(2) evolution rate can reach up to 3.15 mmol g^(−1) h^(−1),which is about 67 times greater than that of pristine TpPa-1-COF,also surpassing that of state-of-the-art metal-free-based photocatalysts reported to date.In particular,it is the first work for constructing COFs-based heterojunctions with the help of h-BN,which may provide new avenue for designing highly efficient metal-free-based photocatalysts for H_(2) evolution.展开更多
There are multiple contaminants in practical wastewater;and the photodegradation of mixed pollutants is a challenge in the field of photocatalysis.Herein,we design a mesoporous 2D/2D TiO_(2)(B)-BiOBr heterojunction ph...There are multiple contaminants in practical wastewater;and the photodegradation of mixed pollutants is a challenge in the field of photocatalysis.Herein,we design a mesoporous 2D/2D TiO_(2)(B)-BiOBr heterojunction photocatalyst for the photodegradation of mixed pollutants.Such a coupling structure results in an enhancement in the disconnection of photoexcited carriers,and the increase of absorption and reaction sites.The 2D/2D TiO_(2)(B)-BiOBr demonstrates outstanding photocatalytic activity for photodegrading rhodamine B(RhB),methyl orange(MO),tetracycline hydrochloride(TCH),and bisphenol A(BPA)simultaneously under visible light,which is 4.7,1.4,23 and 16.4 times as high as that of original BiOBr,respectively.Our work represents a possible solution to devise promising and efficient photocatalysts for the treatment of practical wastewater in the near future.展开更多
A two-dimensional(2D)/2D hybrid heterojunction with face-to-face interfacial assembly is a desirable dimensionality design with significant potential for various photocatalytic applications due to the large interfacia...A two-dimensional(2D)/2D hybrid heterojunction with face-to-face interfacial assembly is a desirable dimensionality design with significant potential for various photocatalytic applications due to the large interfacial contact area,which facilitates charge migration and separation.Herein,we developed an ef-ficient 2D/2D hybrid heterojunction consisting of BiOIO 3 nanoplates(BIO)and g-C_(3)N_(4) nanosheets(CN)using a simple but effective in situ growth method for photocatalytic aqueous antibiotic degradation and H_(2) generation.The face-to-face interfacial assembly of the BIO and CN components in the BIO/CN hy-brid heterojunction was verified using electron microscopy.Remarkably,the BIO/CN hybrid heterojunc-tion outperformed both the BIO and CN counterparts in terms of norfloxacin degradation and H_(2) gen-eration under simulated solar light irradiation.Moreover,the photocatalytic performance of the hybrid catalyst remained nearly unchanged throughout five consecutive test runs.The exceptional performance and stability of the hybrid catalyst are attributable to its extended optical absorption range,large interfa-cial contact area provided by the face-to-face assembly in the 2D/2D hybrid configuration,and enhanced photoexcited charge separation efficiency and redox power of the separated charges,which are supported by an efficient S-scheme charge transfer mechanism.This study illuminates the rational construction of novel 2D/2D S-scheme hybrid heterojunction photocatalysts with practical applications in environmental remediation and sustainable energy generation.展开更多
Fabrication of 2D/2D heterojunction photocatalysts have attracted more attentions due to their inherent merits involving the large contact interface,short charge migration distance and plentiful active sites,which are...Fabrication of 2D/2D heterojunction photocatalysts have attracted more attentions due to their inherent merits involving the large contact interface,short charge migration distance and plentiful active sites,which are beneficial for the enhancement of photocatalytic activity.Herein,a series of 2D/2D MoS_(2)/Cd S type-I heterojunctions were prepared by incorporation the exfoliating of bulk CdS and MoS_(2) with postsintering procedure.Multiple characteristic techniques were employed to corroborate the formation of heterojunctions.By optimizing the 2D MoS_(2) amounts in the heterojunction,the 7 wt.%2D/2D MoS_(2)/CdS heterojunction displayed the maximal photocatalytic H2 evolution rate of 18.43 mmol h^(-1) g^(-1) under visible light irradiation in the presence of lactic acid as the sacrificial reagent,which was 6 times higher than that of pristine 2D CdS.Based on the photoelectrochemical and photoluminescence spectra tests,it could be deduced that the charge separation and transfer of 2D/2D MoS_(2)/CdS heterojunction was tremendously improved,and the recombination of photoinduced electron-hole pairs was effectively impeded.Moreover,the 2D MoS_(2) was used as a cocatalyst to provide the abundant active sites and lower the overpotential for H_(2) generation reaction.The current work would offer an insight to fabricate the 2D/2D heterojunction photocatalysts for splitting H_(2)O into H_(2).展开更多
In this work,a set of novel Cu2ZnSnS4/Bi2WO6(CZTS/BWO)two-dimensional(2 D)/two-dimensional(2 D)type-Ⅱheterojunctions with different CZTS weight ratios(1%,2%,and 5%)were successfully synthesized via a brief secondary ...In this work,a set of novel Cu2ZnSnS4/Bi2WO6(CZTS/BWO)two-dimensional(2 D)/two-dimensional(2 D)type-Ⅱheterojunctions with different CZTS weight ratios(1%,2%,and 5%)were successfully synthesized via a brief secondary solvothermal process.The successful formation of the heterojunctions was affirmed by characterization methods such as X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy.The photocatalytic activity results showed that the prepared CZTS/BWO heterojunctions had excellent photocatalytic behaviors for organic degradation,especially when the mass fraction of CZTS with respect to BWO in the composite was 2%.Moreover,the addition of hydrogen peroxide(H2O2)could further improve the dye and antibiotic degradation efficiencies.The reinforced photocatalytic and photo-Fenton degradation performance were primarily attributable to the introduction of BWO,which afforded increased active sites,expanded the solar spectral response range,and accelerated the cycle of Cu(Ⅱ)/Cu(Ⅰ);after four cycling times,its catalytic activity did not decrease significantly.In addition,reasonable hypotheses of the photocatalytic and photo-Fenton catalytic mechanisms were formulated.This study is expected to provide a visual approach for designing a novel photo-Fenton catalyst to jointly utilize the photocatalytic and Fenton activities,which can be better applied to the purification of residual organics in wastewater.展开更多
The fabrication of S-scheme heterojunctions with fast charge transfer and good interface contacts,such as intermolecularπ–πinteractions,is a promising approach to improve photocatalytic performance.A unique two-dim...The fabrication of S-scheme heterojunctions with fast charge transfer and good interface contacts,such as intermolecularπ–πinteractions,is a promising approach to improve photocatalytic performance.A unique two-dimensional/two-dimensional(2D/2D)S-scheme heterojunction containing TpPa-1-COF/g-C_(3)N_(4) nanosheets(denoted as TPCNNS)was developed.The established maximum interfacial interaction between TpPa-1-COF NS and g-C_(3)N_(4) NS may result in aπ–πconjugated heterointerface.Furthermore,the difference in the work functions of TpPa-1-COF and g-C_(3)N_(4) results in a large Fermi level gap,leading to upward/downward band edge bending.The spontaneous interfacial charge transfer from g-C_(3)N_(4) to TpPa-1-COF at theπ–πconjugated interface area results in the presence of a built-in electric field,according to the charge density difference analysis based on density functional theory calculations.Such an enhanced built-in electric field can efficiently drive directional charge migration via the S-scheme mechanism,which enhances charge separation and utilization.Thus,an approximately 2.8 and 5.6 times increase in the photocatalytic hydrogen evolution rate was recorded in TPCNNS-2(1153μmol g^(-1) h^(-1))compared to pristine TpPa-1-COF and g-C_(3)N_(4) NS,respectively,under visible light irradiation.Overall,this work opens new avenues in the fabrication of 2D/2Dπ–πconjugated S-scheme heterojunction photocatalysts with highly efficient hydrogen evolution performance.展开更多
Low-efficiency charge transfer is a critical factor to limit the photocatalytic H_(2)evolution activity of semiconductor photocatalysts.The interface design is a promising approach to achieve high chargetransfer effic...Low-efficiency charge transfer is a critical factor to limit the photocatalytic H_(2)evolution activity of semiconductor photocatalysts.The interface design is a promising approach to achieve high chargetransfer efficiency for photocatalysts.Herein,a new 2 D/2 D atomic double-layer WS_(2)/Nb_(2)O_(5)shell/core photocatalyst(DLWS/Nb_(2)O_(5))is designed.The atom-resolved HAADF-STEM results unravel the presence of an unusual 2 D/2 D shell/core interface in DLWS/Nb_(2)O_(5).Taking advantage of the advanced femtosecond-resolved ultrafast TAS spectra,the average lifetime of charge carriers for DLWS/Nb_(2)O_(5)(180.97 ps)is considerably shortened as compared to that of Nb_(2)O_(5)(230.50 ps),strongly indicating that the 2 D/2 D shell/core interface enables DLWS/Nb_(2)O_(5)to achieve ultrafast charge transfer from Nb_(2)O_(5)to atomic double-layer WS_(2),thus yielding a high photocatalytic H_(2)evolution rate of 237.6 mmol/h,up to10.8 times higher than that of pure Nb_(2)O_(5)nanosheet.This study will open a new window for the development of high-efficient photocatalytic systems through the interface design.展开更多
Layered transition metal hydroxides show distinct advantages in separately co-catalyzing CO_(2)reduction and H_(2)O oxidation at the electron-accumulating and hole-accumulating sites of wrapped heterojunction photocat...Layered transition metal hydroxides show distinct advantages in separately co-catalyzing CO_(2)reduction and H_(2)O oxidation at the electron-accumulating and hole-accumulating sites of wrapped heterojunction photocatalysts,while concurrently preventing side reactions and photocorrosion on the semiconductor surface.Herein,Ni-Co bimetallic hydroxides with varying Ni/Co molar ratios(Ni_(x)Co_(1-x)(OH)_(2),x=1,0.75,0.5,0.25,and 0)were grown in situ on a model 2D/2D S-scheme heterojunction composed of Cu_(2)O nanosheets and Fe_(2)O_(3)nanoplates to form a series of Cu_(2)O/Fe_(2)O_(3)@Ni_(x)Co_(1-x)(OH)_(2)(CF@NiCo)photocatalysts.The combined experimental and theoretical investigation demonstrates that incorporating an appropriate amount of Co into Ni(OH)_(2)not only modulates the energy band structure of Ni_(x)Co_(1-x)(OH)_(2),balances the electron-and hole-trapping abilities of the bifunctional cocatalyst and maximizes the charge separation efficiency of the heterojunction,but also regulates the d-band center of Ni_(x)Co_(1-x)(OH)_(2),reinforcing the adsorption and activation of CO_(2)and H_(2)O on the cocatalyst surface and lowering the rate-limiting barriers in the CO_(2)-to-CO and H_(2)O-to-O_(2)conversion.Benefiting from the Ni-Co synergy,the redox reactions proceed stoichiometrically.The optimized CF@Ni_(0.75)Co_(0.25)achieves CO and O_(2)yields of 552.7 and 313.0μmol gcat^(-1)h^(-1),respectively,11.3/9.9,1.6/1.7,and 4.5/5.9-fold higher than those of CF,CF@Ni,and CF@Co.This study offers valuable insights into the design of bifunctional noble-metal-free cocatalysts for high-performance artificial photosynthesis.展开更多
基金supported by the National Natural Science Foundation of China(No.21773089)the Henan Center for Outstanding Overseas Scientist(No.GZS2024004).
文摘Herein,a new type of two-dimensional(2D)/2D Ti_(3)C_(2)/TiO_(2) heterojunction was developed for efficient photocatalytic nitrogen reduction reaction(NRR),in which TiO_(2) nanosheets(TiO_(2) Ns)were designed as the main catalyst,while Ti_(3)C_(2) MXene served as the co-catalyst.Experimental and theoretical results revealed that Ti_(3)C_(2) MXene introduced electron-rich unsaturated Ti sites,serving as highly active sites for both the adsorption and activation of N_(2) on the Ti_(3)C_(2)/TiO_(2) heterojunction.Furthermore,the 2D/2D Ti_(3)C_(2)/TiO_(2) heterostructure greatly promoted the directional separation and transfer of charge carriers,facilitated by the internal electric field.This structural feature enabled the spatial separation of the N_(2) reduction and H2 O oxidation half-reactions on the distinct surfaces of Ti_(3)C_(2)(001)and TiO_(2)(001),con-sequently reducing the reaction energy barrier for each respective process.The synergistic effects arising from the interface and surface interactions within the heterojunction conspicuously improved the photo-catalytic NRR activity.As a result,the optimized Ti_(3)C_(2)/TiO_(2) heterojunction exhibited a high NH_(3) produc-tion rate of 24.4μmol g−1 h−1 in the absence of sacrificial agents,representing a remarkable 12.8-fold increase compared to individual TiO_(2) Ns.This work provides new insights into rational design of high-performance heterogeneous photocatalysts and offers a deeper understanding of the mechanism under-lying surface active sites in the photocatalytic NRR process.
基金Ministry of Higher Education(MOHE)Malaysia under the Fundamental Research Grant Scheme(FRGS)(Ref No:FRGS/1/2020/TK0/XMU/02/1)We would also like to thank the Ministry of Science,Technology and Innovation(MOSTI)Malaysia under the Strategic Research Fund(SRF-APP)(S.22015)+5 种基金The authors would also like to acknowledge the financial support provided by the National Natural Science Foundation of China(Ref No.22202168)Guangdong Basic and Applied Basic Re-search Foundation(Ref No.2021A1515111019)We would also like to acknowledge the financial support from the State Key Labo-ratory of Physical Chemistry of Solid Surfaces,Xiamen University(No.2023X11)This work is also funded by Xiamen University Malaysia Investigatorship Grant(Grant No.IENG/0038)Xiamen University Malaysia Research Fund(ICOE/0001,XMUMRF/2021-C8/IENG/0041 and XMUMRF/2019-C3/IENG/0013)Hengyuan International Sdn.Bhd.(Grant No.EENG/0003).
文摘Two-dimensional(2D)materials have come to light due to their unique thickness that owns abundant exposed edges with enhanced electrocatalytic properties.2D molybdenum disulfide(MoS_(2))nanosheet has aroused considerable attention due to its tunable surface chemistry and high electrochemical sur-face area.Nonetheless,several shortcomings associated with MoS_(2),such as its naturally existing semi-conducting 2H phase,which has limited active sites due to the inert basal plane,restrict its application in water electrocatalysis.Taking into account the benefits of the 1T/2H phase of MoS_(2),as well as the importance of engineering 2D/2D heterojunction interface for boosted electrocatalysis,metallic Ti_(3)C_(2)Tx was integrated with 1T/2H MoS_(2) to develop 2D/2D 1T/2H MoS_(2)/Ti_(3)C_(2)Tx heterostructured nanocompos-ites.Herein,with only 25%of the intercalating agent,1T/2H MoS_(2) with the highest 1T phase content of~82%was successfully synthesized.It was further incorporated with 1 wt%of Ti_(3)C_(2)Tx through a com-bination of ultrasonication and mechanical stirring process.The 1T/2H MoS_(2)(25D)/Ti_(3)C_(2)Tx-1(MTC-1)manifested outstanding electrocatalytic performance with an overpotential and Tafel slope of 280 mV(83.80 mV dec^(-1))and 300 mV(117.2 mV dec^(-1)),for catalyzing acidic and alkaline medium HER,respec-tively.Pivotally,the as-prepared catalysts also illustrated long-term stability for more than 40 h.The coupling method for the 2D nanosheets is crucial to suppress the oxidation of Ti_(3)C_(2)Tx and the restack-ing issue of 2D nanosheets.The superior HER activity is ascribed to the synergistic effect between the heterostructure,enhancing the electronic structure and charge separation capability.The intrinsic prop-erty of the catalyst further confirms by turnover frequency(TOF)calculation.As such,this research paves the way for designing high-efficiency 2D electrocatalysts and sheds light on the further advancement of tunable 2D electrocatalysts for robust water splitting and beyond.
基金financially supported by the National Natural Science Foundation of China (No.52106259)the Fundamental Research Funds for the Central Universities (2024MS013)Key Research and Development Program of Shaanxi (Program No.2022LL-JB-08)。
文摘Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S_(4) heterostructures with strong hetero-interface interaction and abundant contact were constructed via an impregnation-annealing strategy.Efficient charge transfer from ZnIn_(2)S_(4) to WSe_(2)was evidenced by transient absorption spectroscopy in crafted heterostructures owing to the tight and2D face-to-face contact.As a result,the prepared WSe_(2)/ZnIn_(2)S_(4) heterostructures exhibited boosted photocatalytic performance and a highest hydrogen evolution rate of 3.377 mmol/(g h)was achieved with an apparent quantum yield of 45.7%at 420 nm.The work not only provides new strategies to achieve efficient 2D/2D heterostructures but also paves the way for the development of green hydrogen in the future.
文摘The design and construction of heterojunction photocatalysts,which possess a staggered energy band structure and appropriate interfacial contact,is an effective way to achieve outstanding photocatalytic performance.In this study,2D/2D BiOBr/g‐C_(3)N_(4)heterojunctions were successfully obtained by a convenient in situ self‐assembly route.Under simulated sunlight irradiation,99%of RhB(10 mg·L–1,100 mL)was efficiently degraded by 1.5‐BiOBr/g‐C_(3)N_(4)within 30 min,which is better than the performance of both BiOBr and g‐C_(3)N_(4),and it has superior stability.In addition,the composite also exhibits enhanced photocatalytic activity for H2 production.The enhanced activity can be attributed to the intimate interface contact,the larger surface area,and the highly efficient separation of photoinduced electron–hole pairs.Based on the experimental results,a novel S‐scheme model was proposed to illuminate the transfer process of charge carriers.This study presents a simple way to develop novel step‐scheme photocatalysts for environmental and related applications.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.JUSRP51716A)the National Natural Science Foundation of China(Nos.21203077 and 21773099)the financially support from the Qing Lan Project of Jiangsu Province。
文摘A novel 2D/2D Bi_(2)MoO_(6)/g-C_(3)N_(4) step-scheme(S-scheme)composite by loading Au as cocatalyst was successfully fabricated using a photoreduction and hydrothermal route.The obtained Bi_(2)MoO_(6)/g-C_(3)N_(4)/Au photocatalysts were characterized by X-ray diffraction(XRD),transmission electron microscope(TEM),X-ray photo-electron spectroscopy(XPS),UV–vis diffuse reflectance spectra(UV–vis),Fourier transform infrared spectroscopy(FTIR),photoluminescence(PL),photocurrent response(I-t),and electrochemical impedance spectroscopy(EIS).The HRTEM images revealed that an intimate interface in composites were formed.The optimum photocatalytic activity of Rhodamine B degradation over Bi_(2)MoO_(6)/g-C_(3)N_(4)/Au was about 9.7 times and 13.1 times as high as those of Bi_(2)MoO_(6) and g-C_(3)N_(4),respectively.The notably improved photocatalytic activity of Bi_(2)MoO_(6)/g-C_(3)N_(4)/Au could be mainly ascribed to the abundant active sites and the enhanced separation efficiency of photogenerated carriers in Bi_(2)MoO_(6)/g-C_(3)N_(4) S-scheme system.Notably,Au nanoparticles could act as a co-catalyst to further promote electron transfer and separation from the conduction band of g-C_(3)N_(4).Additionally,a possible step-scheme photocatalytic reaction mechanism of Rh B degradation over Bi_(2)MoO_(6)/g-C_(3)N_(4)/Au was tentatively proposed.PL and transient photocurrent analysis implied that Bi_(2)MoO_(6)/g-C_(3)N_(4)/Au photocatalysts possessed the lower recombination rate of photogenerated carriers compared with pure Bi_(2) MoO_(6) and g-C_(3)N_(4),respectively.The present work is expected to provide useful information in designing 2D/2D S-scheme heterojunction photocatalysts.
文摘Reducing CO_(2) to hydrocarbon fuels by solar irradiation provides a feasible channel for mitigating excessive CO_(2) emissions and addressing resource depletion.Nevertheless,severe charge recombi‐nation and the high energy barrier for CO_(2) photoreduction on the surface of photocatalysts com‐promise the catalytic performance.Herein,a 2D/2D Bi_(2)MoO_(6)/BiOI composite was fabricated to achieve improved CO_(2) photoreduction efficiency.Charge transfer in the composite was facilitated by the van der Waals heterojunction with a large‐area interface.Work function calculation demon‐strated that S‐scheme charge transfer is operative in the composite,and effective charge separation and strong redox capability were revealed by time‐resolved photoluminescence and electron para‐magnetic resonance spectroscopy.Moreover,the intermediates of CO_(2) photoreduction were identi‐fied based on the in situ diffuse reflectance infrared Fourier‐transform spectra.Density functional theory calculations showed that CO_(2) hydrogenation is the rate‐determining step for yielding CH_(4) and CO.Introducing Bi_(2)MoO_(6) into the composite further decreased the energy barrier for CO_(2) photoreduction on BiOI by 0.35 eV.This study verifies the synergistic effect of the S‐scheme heterojunction and van der Waals heterojunction in the 2D/2D composite.
基金supported by Zhejiang Provincial Natural Science Foundation of China (No. LY18F010009)Ningbo Natural Science Foundation (No. 2018A610002)
文摘Two-dimensional(2D)nanomaterials have demonstrated great potential in the field of flexible gas sensing due to their inherent high specific surface areas,unique electronic properties and flexibility property.However,numerous challenges including sensitivity,selectivity,response time,recovery time,and stability have to be addressed before their practical application in gas detection field.Development of graphene-like 2D/2D nanocomposites as an efficient strategy to achieve high-performance 2D gas sensor has been reported recently.This review aims to discuss the latest advancements in the 2D/2D nanocomposites for gas sensors.We first elaborate the gas-sensing mechanisms and the collective benefits of 2D/2D hybridization as sensor materials.Then,we systematically present the current gas-sensing applications based on different categories of 2D/2D nanocomposites.Finally,we conclude the future prospect of 2D/2D nanocomposites in gas sensing applications.
基金supported by the National Natural Science Foundation of China(Nos.22101105,52071171,52202248)the Research Fund for the Doctoral Program of Liaoning Province(2021-BS-086)+6 种基金Liaoning BaiQianWan Talents Program(LNBQW2018B0048)Shenyang Science and Technology Project(21-108-9-04)Australian Research Council(ARC)through Future Fellowship(FT210100298,FT210100806)Discovery Project(DP220100603)Linkage Project(LP210100467,LP210200504,LP210200345,LP220100088)Industrial Transformation Training Centre(IC180100005)schemesthe Australian Government through the Cooperative Research Centres Projects(CRCPXIII000077).
文摘Covalent organic frameworks(COFs)have emerged as a kind of rising star materials in photocatalysis.However,their photocatalytic activities are restricted by the high photogenerated electron-hole pairs recombination rate.Herein,a novel metal-free 2D/2D van der Waals heterojunction,composed of a two-dimensional(2D)COF with ketoenamine linkage(TpPa-1-COF)and 2D defective hexagonal boron nitride(h-BN),is successfully constructed through in situ solvothermal method.Benefitting from the presence of VDW heterojunction,larger contact area and intimate electronic coupling can be formed between the interface of TpPa-1-COF and defective h-BN,which make contributions to promoting charge car-riers separation.The introduced defects can also endow the h-BN with porous structure,thus providing more reactive sites.Moreover,the TpPa-1-COF will undergo a structural transformation after being integrated with defective h-BN,which can enlarge the gap between the conduction band position of the h-BN and TpPa-1-COF,and suppress electron backflow,corroborated by experimental and density functional theory calculations results.Accordingly,the resulting porous h-BN/TpPa-1-COF metal-free VDW heterojunction displays out-standing solar energy catalytic activity for water splitting without co-catalysts,and the H_(2) evolution rate can reach up to 3.15 mmol g^(−1) h^(−1),which is about 67 times greater than that of pristine TpPa-1-COF,also surpassing that of state-of-the-art metal-free-based photocatalysts reported to date.In particular,it is the first work for constructing COFs-based heterojunctions with the help of h-BN,which may provide new avenue for designing highly efficient metal-free-based photocatalysts for H_(2) evolution.
基金funding support from the National Science Foundation of China(NO.220413201)。
文摘There are multiple contaminants in practical wastewater;and the photodegradation of mixed pollutants is a challenge in the field of photocatalysis.Herein,we design a mesoporous 2D/2D TiO_(2)(B)-BiOBr heterojunction photocatalyst for the photodegradation of mixed pollutants.Such a coupling structure results in an enhancement in the disconnection of photoexcited carriers,and the increase of absorption and reaction sites.The 2D/2D TiO_(2)(B)-BiOBr demonstrates outstanding photocatalytic activity for photodegrading rhodamine B(RhB),methyl orange(MO),tetracycline hydrochloride(TCH),and bisphenol A(BPA)simultaneously under visible light,which is 4.7,1.4,23 and 16.4 times as high as that of original BiOBr,respectively.Our work represents a possible solution to devise promising and efficient photocatalysts for the treatment of practical wastewater in the near future.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.NRF-2018R1A5A1025137).
文摘A two-dimensional(2D)/2D hybrid heterojunction with face-to-face interfacial assembly is a desirable dimensionality design with significant potential for various photocatalytic applications due to the large interfacial contact area,which facilitates charge migration and separation.Herein,we developed an ef-ficient 2D/2D hybrid heterojunction consisting of BiOIO 3 nanoplates(BIO)and g-C_(3)N_(4) nanosheets(CN)using a simple but effective in situ growth method for photocatalytic aqueous antibiotic degradation and H_(2) generation.The face-to-face interfacial assembly of the BIO and CN components in the BIO/CN hy-brid heterojunction was verified using electron microscopy.Remarkably,the BIO/CN hybrid heterojunc-tion outperformed both the BIO and CN counterparts in terms of norfloxacin degradation and H_(2) gen-eration under simulated solar light irradiation.Moreover,the photocatalytic performance of the hybrid catalyst remained nearly unchanged throughout five consecutive test runs.The exceptional performance and stability of the hybrid catalyst are attributable to its extended optical absorption range,large interfa-cial contact area provided by the face-to-face assembly in the 2D/2D hybrid configuration,and enhanced photoexcited charge separation efficiency and redox power of the separated charges,which are supported by an efficient S-scheme charge transfer mechanism.This study illuminates the rational construction of novel 2D/2D S-scheme hybrid heterojunction photocatalysts with practical applications in environmental remediation and sustainable energy generation.
基金financially supported by the Science and Technology Investigation Project of Hubei Provincial Department of Education,China(No.D20181805)。
文摘Fabrication of 2D/2D heterojunction photocatalysts have attracted more attentions due to their inherent merits involving the large contact interface,short charge migration distance and plentiful active sites,which are beneficial for the enhancement of photocatalytic activity.Herein,a series of 2D/2D MoS_(2)/Cd S type-I heterojunctions were prepared by incorporation the exfoliating of bulk CdS and MoS_(2) with postsintering procedure.Multiple characteristic techniques were employed to corroborate the formation of heterojunctions.By optimizing the 2D MoS_(2) amounts in the heterojunction,the 7 wt.%2D/2D MoS_(2)/CdS heterojunction displayed the maximal photocatalytic H2 evolution rate of 18.43 mmol h^(-1) g^(-1) under visible light irradiation in the presence of lactic acid as the sacrificial reagent,which was 6 times higher than that of pristine 2D CdS.Based on the photoelectrochemical and photoluminescence spectra tests,it could be deduced that the charge separation and transfer of 2D/2D MoS_(2)/CdS heterojunction was tremendously improved,and the recombination of photoinduced electron-hole pairs was effectively impeded.Moreover,the 2D MoS_(2) was used as a cocatalyst to provide the abundant active sites and lower the overpotential for H_(2) generation reaction.The current work would offer an insight to fabricate the 2D/2D heterojunction photocatalysts for splitting H_(2)O into H_(2).
基金supported by the National Natural Science Foundation of China(21663030,21666039)the Open Project of State Key Laboratory of Organic-Inorganic Composites Beijing Key Laboratory,Beijing University of Chemical Technology(oic-201901009)+2 种基金the Project of Science&Technology Office of Shannxi Province(2018TSCXL-NY-02-01,2013K11-08,2013SZS20-P01)Industrial Key Project of Yan’an Science and Technology Bureau(2018KG-04)the Project of Yan’an Science Graduate Innovation Project of Yan’an University(YCX201988)~~
文摘In this work,a set of novel Cu2ZnSnS4/Bi2WO6(CZTS/BWO)two-dimensional(2 D)/two-dimensional(2 D)type-Ⅱheterojunctions with different CZTS weight ratios(1%,2%,and 5%)were successfully synthesized via a brief secondary solvothermal process.The successful formation of the heterojunctions was affirmed by characterization methods such as X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy.The photocatalytic activity results showed that the prepared CZTS/BWO heterojunctions had excellent photocatalytic behaviors for organic degradation,especially when the mass fraction of CZTS with respect to BWO in the composite was 2%.Moreover,the addition of hydrogen peroxide(H2O2)could further improve the dye and antibiotic degradation efficiencies.The reinforced photocatalytic and photo-Fenton degradation performance were primarily attributable to the introduction of BWO,which afforded increased active sites,expanded the solar spectral response range,and accelerated the cycle of Cu(Ⅱ)/Cu(Ⅰ);after four cycling times,its catalytic activity did not decrease significantly.In addition,reasonable hypotheses of the photocatalytic and photo-Fenton catalytic mechanisms were formulated.This study is expected to provide a visual approach for designing a novel photo-Fenton catalyst to jointly utilize the photocatalytic and Fenton activities,which can be better applied to the purification of residual organics in wastewater.
文摘The fabrication of S-scheme heterojunctions with fast charge transfer and good interface contacts,such as intermolecularπ–πinteractions,is a promising approach to improve photocatalytic performance.A unique two-dimensional/two-dimensional(2D/2D)S-scheme heterojunction containing TpPa-1-COF/g-C_(3)N_(4) nanosheets(denoted as TPCNNS)was developed.The established maximum interfacial interaction between TpPa-1-COF NS and g-C_(3)N_(4) NS may result in aπ–πconjugated heterointerface.Furthermore,the difference in the work functions of TpPa-1-COF and g-C_(3)N_(4) results in a large Fermi level gap,leading to upward/downward band edge bending.The spontaneous interfacial charge transfer from g-C_(3)N_(4) to TpPa-1-COF at theπ–πconjugated interface area results in the presence of a built-in electric field,according to the charge density difference analysis based on density functional theory calculations.Such an enhanced built-in electric field can efficiently drive directional charge migration via the S-scheme mechanism,which enhances charge separation and utilization.Thus,an approximately 2.8 and 5.6 times increase in the photocatalytic hydrogen evolution rate was recorded in TPCNNS-2(1153μmol g^(-1) h^(-1))compared to pristine TpPa-1-COF and g-C_(3)N_(4) NS,respectively,under visible light irradiation.Overall,this work opens new avenues in the fabrication of 2D/2Dπ–πconjugated S-scheme heterojunction photocatalysts with highly efficient hydrogen evolution performance.
基金funded by the China Postdoctoral Science Foundation(pre-station,No.2019TQ0050)Applied Basic Research Program of Sichuan Province(No.2020YJ0068)+5 种基金the China Postdoctoral Science Foundation(No.2020M673186)National Natural Science Foundation of China(No.22002014)National Natural Science Foundation of China(No.11804248)the financial support from the National Natural Science Foundation of China(No.21971113)Natural Science Foundation of Tianjin(No.18JCQNJC03200)supported by MOE Tier 1 RG4/17 and MOE Tier 2 MOE2019-T2-2-105。
文摘Low-efficiency charge transfer is a critical factor to limit the photocatalytic H_(2)evolution activity of semiconductor photocatalysts.The interface design is a promising approach to achieve high chargetransfer efficiency for photocatalysts.Herein,a new 2 D/2 D atomic double-layer WS_(2)/Nb_(2)O_(5)shell/core photocatalyst(DLWS/Nb_(2)O_(5))is designed.The atom-resolved HAADF-STEM results unravel the presence of an unusual 2 D/2 D shell/core interface in DLWS/Nb_(2)O_(5).Taking advantage of the advanced femtosecond-resolved ultrafast TAS spectra,the average lifetime of charge carriers for DLWS/Nb_(2)O_(5)(180.97 ps)is considerably shortened as compared to that of Nb_(2)O_(5)(230.50 ps),strongly indicating that the 2 D/2 D shell/core interface enables DLWS/Nb_(2)O_(5)to achieve ultrafast charge transfer from Nb_(2)O_(5)to atomic double-layer WS_(2),thus yielding a high photocatalytic H_(2)evolution rate of 237.6 mmol/h,up to10.8 times higher than that of pure Nb_(2)O_(5)nanosheet.This study will open a new window for the development of high-efficient photocatalytic systems through the interface design.
文摘Layered transition metal hydroxides show distinct advantages in separately co-catalyzing CO_(2)reduction and H_(2)O oxidation at the electron-accumulating and hole-accumulating sites of wrapped heterojunction photocatalysts,while concurrently preventing side reactions and photocorrosion on the semiconductor surface.Herein,Ni-Co bimetallic hydroxides with varying Ni/Co molar ratios(Ni_(x)Co_(1-x)(OH)_(2),x=1,0.75,0.5,0.25,and 0)were grown in situ on a model 2D/2D S-scheme heterojunction composed of Cu_(2)O nanosheets and Fe_(2)O_(3)nanoplates to form a series of Cu_(2)O/Fe_(2)O_(3)@Ni_(x)Co_(1-x)(OH)_(2)(CF@NiCo)photocatalysts.The combined experimental and theoretical investigation demonstrates that incorporating an appropriate amount of Co into Ni(OH)_(2)not only modulates the energy band structure of Ni_(x)Co_(1-x)(OH)_(2),balances the electron-and hole-trapping abilities of the bifunctional cocatalyst and maximizes the charge separation efficiency of the heterojunction,but also regulates the d-band center of Ni_(x)Co_(1-x)(OH)_(2),reinforcing the adsorption and activation of CO_(2)and H_(2)O on the cocatalyst surface and lowering the rate-limiting barriers in the CO_(2)-to-CO and H_(2)O-to-O_(2)conversion.Benefiting from the Ni-Co synergy,the redox reactions proceed stoichiometrically.The optimized CF@Ni_(0.75)Co_(0.25)achieves CO and O_(2)yields of 552.7 and 313.0μmol gcat^(-1)h^(-1),respectively,11.3/9.9,1.6/1.7,and 4.5/5.9-fold higher than those of CF,CF@Ni,and CF@Co.This study offers valuable insights into the design of bifunctional noble-metal-free cocatalysts for high-performance artificial photosynthesis.
