Pyrolysis of the Ta_(2)_(O5)/melamine mixture in molten chlorides is herein demonstrated as a facile and controllable method to nitridize and functionalize Ta_(2)_(O5).The influence of the stoichiometry and compositio...Pyrolysis of the Ta_(2)_(O5)/melamine mixture in molten chlorides is herein demonstrated as a facile and controllable method to nitridize and functionalize Ta_(2)_(O5).The influence of the stoichiometry and composition of Ta_(2)_(O5)/melamine in molten salts on the nitridation process is rationalized to ensure the controllable preparation of Ta_(3)N_(5) and Ta_(3)N_(5)/TaON.The characterization results,including scanning electron microscopy,transmission electron microscopy,elemental mapping,X-ray photoelectron spectroscopy,and photoluminescence spectroscopy,all confirm the existence of the Ta_(3)N_(5)/TaON heterojunction,in which the TaON nanoparticles are closely anchored to the Ta_(3)N_(5) nanorods.Benefiting from its composition and structure,the Ta_(3)N_(5)/TaON composites show enhanced photocatalytic activity for the degradation of methylene blue.The present study highlights that the molten salt method using a solid nitrogen source can be a new technique for rationalizing the design of nitrides and oxynitrides.展开更多
Ta_(3)N_(5)/CdS core–shell S-scheme heterojunction nanofibers are fabricated by in situ growing CdS nanodots on Ta_(3)N_(5) nanofib-ers via a simple wet-chemical method.These Ta_(3)N_(5)/CdS nanofibers not only affor...Ta_(3)N_(5)/CdS core–shell S-scheme heterojunction nanofibers are fabricated by in situ growing CdS nanodots on Ta_(3)N_(5) nanofib-ers via a simple wet-chemical method.These Ta_(3)N_(5)/CdS nanofibers not only affords superior photocatalytic tetracycline degradation and mineralization performance,but also cause an efficient photocatalytic Cr(VI)reduction performance.The creation of favorable core–shell fiber-shaped S-scheme hetero-structure with tightly contacted interface and the maximum interface contact area promises the effective photo-carrier disintegration and the optimal photo-redox capacity synchronously,thus leading to the preeminent photo-redox ability.Some critical environmental factors on the photo-behavior of Ta_(3)N_(5)/CdS are also evaluated in view of the complexity of the authentic aquatic environment.The degradation products of tetracycline were confirmed by HPLC–MS analyses.Furthermore,the effective decline in eco-toxicity of TC intermediates is confirmed by QSAR calculation.This work provides cutting-edge guidelines for the design of high-performance Ta_(3)N_(5)-based S-scheme heterojunction nanofibers for environment restoration.展开更多
Charge separation is generally considered as the most critical step to achieve efficient photocatalytic reactions. Although charge separation can be promoted by a semiconductor heterojunction, its efficacy is inherent...Charge separation is generally considered as the most critical step to achieve efficient photocatalytic reactions. Although charge separation can be promoted by a semiconductor heterojunction, its efficacy is inherently restrained by the mismatched atomic arrangements across the heterojunction interfaces. Here, Ta3N5–LaTaON2 heterojunction with matched interfaces has been fabricated by one-step ammonolysis treatment of KLaTa2O7. The match interfaces are formed by nearly perfect adhesion of Ta3N5 (010) and LaTaON2 (101¯) facets whose interatomic distance is similar. Compared with conventional heterojunction, the so-formed Ta3N5–LaTaON2 heterojunction are extremely efficient in accelerating charge separation which in turn enables a high photocatalytic activity. An apparent quantum efficiency as high as 11.6% at 420 ± 20 nm has been reached by Ta_(3)N_(5)–LaTaON_(2) heterojunction, which is almost three times higher than Ta_(3)N_(5)-LaTaON_(2) mixtures. These results signify the importance of matched heterojunction interfaces for charge separation and provide a paradigm in the design of efficient heterojunction-based semiconductor photocatalysts.展开更多
Energy crises and environmental pollution have become urgent problems with human civilization development.Photocatalysis technology is a green method to deal with these challenges.The key to improve photocatalytic eff...Energy crises and environmental pollution have become urgent problems with human civilization development.Photocatalysis technology is a green method to deal with these challenges.The key to improve photocatalytic efficiency lies in the effective separation of photogenerated electron-hole pairs.In this work,we designed the Fe atom embedded N-doped graphene oxide(Fe-NGO)supporting on tantalum nitride(Ta_(3)N_(5))catalyst,which was employed to improve the photocatalytic oxygen production activity.The oxygen production of 5 wt%Fe atom embedded N-doped graphene oxide supporting on tantalum nitride(Fe-NGO/Ta_(3)N_(5))was 184.7μmol·g^(-1),about 3.5 times higher than that of the pure Ta_(3)N_(5).The introduction of the cocatalyst Fe-NGO acting as an electron conductor in the Fe-NGO/Ta_(3)N_(5) accelerates the carrier migration of Ta_(3)N_(5) and further enhances the photocatalytic oxygen production activity.N-doping increases the conductivity of graphene oxide(GO),and Fe atoms are used as the reactive sites to promote the combination of electron and sacrificial agent in the system.This work may provide insights into the research of new carbon.展开更多
S-scheme heterojunction photocatalysts have been the“stars”in the field of photocatalysis.Herein,a novel S-scheme heterojunction of Ta_(3)N_(5)/BiOCl with oxygen vacancies(OVs)was fabricated via a facile method.The ...S-scheme heterojunction photocatalysts have been the“stars”in the field of photocatalysis.Herein,a novel S-scheme heterojunction of Ta_(3)N_(5)/BiOCl with oxygen vacancies(OVs)was fabricated via a facile method.The charge separation and transport mechanism of this Ta_(3)N_(5)/BiOCl S-scheme heterojunction was verified by the analyses of band energy structures,active species,photoelectric behaviors and DFT theoretical calculation.Compared with Ta_(3)N_(5)and BiOCl,the Ta_(3)N_(5)/BiOCl unveils substantially upgraded photocatalytic property under visible light,and the photocatalytic efficiency for removal of tetracycline(TC)and hexavalent chromium(Cr(VI))reaches 89.6%and 91.6%,respectively.The substantial enhancement of the photocatalytic activity is attributed to the synergistic effect of the S-scheme hetero-structure and oxygen vacancies,which improves the visible-light absorption,while promoting the spatial separation of charge carriers with the optimum redox capacity,thereby boosting the production of active species for catalytic reactions.The TC degradation pathway is deduced and the toxicity evolution of TC is appraised using the QSAR method.In a nutshell,this work gives a deep understanding of the photocatalytic mechanism based on Ta_(3)N_(5)/BiOCl as well as presents a newfangled thought for developing highly efficient S-scheme heterojunction photocatalysts for water decontamination.展开更多
基金the National Natural Science Foundation of China(Nos.51722404,51674177,51804221,and 91845113)the National Key R&D Program of China(No.2018YFE0201703)+2 种基金the China Postdoctoral Science Foundation(Nos.2018M642906 and 2019T120684)the Fundamental Research Funds for the Central Universities(No.2042019kf0230)the Hubei Provincial Natural Science Foundation of China(No.2019CFA065)。
文摘Pyrolysis of the Ta_(2)_(O5)/melamine mixture in molten chlorides is herein demonstrated as a facile and controllable method to nitridize and functionalize Ta_(2)_(O5).The influence of the stoichiometry and composition of Ta_(2)_(O5)/melamine in molten salts on the nitridation process is rationalized to ensure the controllable preparation of Ta_(3)N_(5) and Ta_(3)N_(5)/TaON.The characterization results,including scanning electron microscopy,transmission electron microscopy,elemental mapping,X-ray photoelectron spectroscopy,and photoluminescence spectroscopy,all confirm the existence of the Ta_(3)N_(5)/TaON heterojunction,in which the TaON nanoparticles are closely anchored to the Ta_(3)N_(5) nanorods.Benefiting from its composition and structure,the Ta_(3)N_(5)/TaON composites show enhanced photocatalytic activity for the degradation of methylene blue.The present study highlights that the molten salt method using a solid nitrogen source can be a new technique for rationalizing the design of nitrides and oxynitrides.
基金supported by the Natural Science Foundation of Zhejiang Province(LY20E080014)the Science and Technology Project of Zhoushan(2022C41011,2020C21009)the National Natural Science Foundation of China(51708504).
文摘Ta_(3)N_(5)/CdS core–shell S-scheme heterojunction nanofibers are fabricated by in situ growing CdS nanodots on Ta_(3)N_(5) nanofib-ers via a simple wet-chemical method.These Ta_(3)N_(5)/CdS nanofibers not only affords superior photocatalytic tetracycline degradation and mineralization performance,but also cause an efficient photocatalytic Cr(VI)reduction performance.The creation of favorable core–shell fiber-shaped S-scheme hetero-structure with tightly contacted interface and the maximum interface contact area promises the effective photo-carrier disintegration and the optimal photo-redox capacity synchronously,thus leading to the preeminent photo-redox ability.Some critical environmental factors on the photo-behavior of Ta_(3)N_(5)/CdS are also evaluated in view of the complexity of the authentic aquatic environment.The degradation products of tetracycline were confirmed by HPLC–MS analyses.Furthermore,the effective decline in eco-toxicity of TC intermediates is confirmed by QSAR calculation.This work provides cutting-edge guidelines for the design of high-performance Ta_(3)N_(5)-based S-scheme heterojunction nanofibers for environment restoration.
基金financially supported by the National Natural Science Foundation of China(Nos.51972233,52172225)Science and Technology Commission of Shanghai Municipality(No.19DZ2271500)the Fundamental Research Funds for the Central Universities.
文摘Charge separation is generally considered as the most critical step to achieve efficient photocatalytic reactions. Although charge separation can be promoted by a semiconductor heterojunction, its efficacy is inherently restrained by the mismatched atomic arrangements across the heterojunction interfaces. Here, Ta3N5–LaTaON2 heterojunction with matched interfaces has been fabricated by one-step ammonolysis treatment of KLaTa2O7. The match interfaces are formed by nearly perfect adhesion of Ta3N5 (010) and LaTaON2 (101¯) facets whose interatomic distance is similar. Compared with conventional heterojunction, the so-formed Ta3N5–LaTaON2 heterojunction are extremely efficient in accelerating charge separation which in turn enables a high photocatalytic activity. An apparent quantum efficiency as high as 11.6% at 420 ± 20 nm has been reached by Ta_(3)N_(5)–LaTaON_(2) heterojunction, which is almost three times higher than Ta_(3)N_(5)-LaTaON_(2) mixtures. These results signify the importance of matched heterojunction interfaces for charge separation and provide a paradigm in the design of efficient heterojunction-based semiconductor photocatalysts.
基金support from the National Natural Science Foundation of China (Nos.22106053,22008095)the China Postdoctoral Science Foundation (Nos.2021M691305,2020TQ0127)the Jiangsu Province Postdoctoral Science Foundation (Nos.2021K079A,2021K396C,2021K382C).
文摘Energy crises and environmental pollution have become urgent problems with human civilization development.Photocatalysis technology is a green method to deal with these challenges.The key to improve photocatalytic efficiency lies in the effective separation of photogenerated electron-hole pairs.In this work,we designed the Fe atom embedded N-doped graphene oxide(Fe-NGO)supporting on tantalum nitride(Ta_(3)N_(5))catalyst,which was employed to improve the photocatalytic oxygen production activity.The oxygen production of 5 wt%Fe atom embedded N-doped graphene oxide supporting on tantalum nitride(Fe-NGO/Ta_(3)N_(5))was 184.7μmol·g^(-1),about 3.5 times higher than that of the pure Ta_(3)N_(5).The introduction of the cocatalyst Fe-NGO acting as an electron conductor in the Fe-NGO/Ta_(3)N_(5) accelerates the carrier migration of Ta_(3)N_(5) and further enhances the photocatalytic oxygen production activity.N-doping increases the conductivity of graphene oxide(GO),and Fe atoms are used as the reactive sites to promote the combination of electron and sacrificial agent in the system.This work may provide insights into the research of new carbon.
基金financially supported by the Natural Science Foundation of Zhejiang Province(No.LY20E080014)the National Natural Science Foundation of China(No.51708504)+1 种基金National Natural Science Foundation of China(No.21975084)the Science and Technology Project of Zhoushan City(No.2020C21009 and 2022C41011)。
文摘S-scheme heterojunction photocatalysts have been the“stars”in the field of photocatalysis.Herein,a novel S-scheme heterojunction of Ta_(3)N_(5)/BiOCl with oxygen vacancies(OVs)was fabricated via a facile method.The charge separation and transport mechanism of this Ta_(3)N_(5)/BiOCl S-scheme heterojunction was verified by the analyses of band energy structures,active species,photoelectric behaviors and DFT theoretical calculation.Compared with Ta_(3)N_(5)and BiOCl,the Ta_(3)N_(5)/BiOCl unveils substantially upgraded photocatalytic property under visible light,and the photocatalytic efficiency for removal of tetracycline(TC)and hexavalent chromium(Cr(VI))reaches 89.6%and 91.6%,respectively.The substantial enhancement of the photocatalytic activity is attributed to the synergistic effect of the S-scheme hetero-structure and oxygen vacancies,which improves the visible-light absorption,while promoting the spatial separation of charge carriers with the optimum redox capacity,thereby boosting the production of active species for catalytic reactions.The TC degradation pathway is deduced and the toxicity evolution of TC is appraised using the QSAR method.In a nutshell,this work gives a deep understanding of the photocatalytic mechanism based on Ta_(3)N_(5)/BiOCl as well as presents a newfangled thought for developing highly efficient S-scheme heterojunction photocatalysts for water decontamination.
