Designing a step-scheme(S-scheme)heterojunction photocatalyst with vacancy engineering is a reliable approach to achieve highly efficient photocatalytic H_(2)production activity.Herein,a hollow ZnO/ZnS S-scheme hetero...Designing a step-scheme(S-scheme)heterojunction photocatalyst with vacancy engineering is a reliable approach to achieve highly efficient photocatalytic H_(2)production activity.Herein,a hollow ZnO/ZnS S-scheme heterojunction with O and Zn vacancies(VO,Zn-ZnO/ZnS)is rationally constructed via ion-exchange and calcination treatments.In such a photocatalytic system,the hollow structure combined with the introduction of dual vacancies endows the adequate light absorption.Moreover,the O and Zn vacancies serve as the trapping sites for photo-induced electrons and holes,respectively,which are beneficial for promoting the photo-induced carrier separation.Meanwhile,the S-scheme charge transfer mechanism can not only improve the separation and transfer efficiencies of photo-induced carrier but also retain the strong redox capacity.As expected,the optimized VO,Zn-ZnO/ZnS heterojunction exhibits a superior photocatalytic H_(2) production rate of 160.91 mmol g^(-1)h^(-1),approximately 643.6 times and 214.5 times with respect to that obtained on pure ZnO and ZnS,respectively.Simultaneously,the experimental results and density functional theory calculations disclose that the photo-induced carrier transfer pathway follows the S-scheme heterojunction mechanism and the introduction of O and Zn vacancies reduces the surface reaction barrier.This work provides an innovative strategy of vacancy engineering in S-scheme heterojunction for solar-to-fuel energy conversion.展开更多
Electron transport layers （ETLs） in perovskite solar cells （PSCs） are a key factor to determine the photo- voltaic performance. Herein, we demonstrate preparation of ZnO/ZnS core-shell composites through di- rectl...Electron transport layers （ETLs） in perovskite solar cells （PSCs） are a key factor to determine the photo- voltaic performance. Herein, we demonstrate preparation of ZnO/ZnS core-shell composites through di- rectly synthesizing ZnS on the ZnO nanoparticles in solution. We confirmed the formation of ZnO/ZnS core-shell composites by the uses of X-ray diffraction patterns and the Fourier transform infrared spec- troscopy. ZnO/ZnS composites exhibit much homogeneous surface morphology as compared with the bare ZnO as revealed in the scanning electronic microscopy. Moreover, the upper shift of conduction band level upon composition of the ZnO/ZnS film results in a better alignment of energy level, which facilitates cas- cade charge extraction and thus improves the current density of perovskite solar cell. The shift of conduc- tion band also improves the voltage of the PSCs. The photoluminescence （PL） spectroscopies measured in both steady and transient states were carried out to characterize the charge extraction at the interface between CH_3NH_3Pbl_3 and the electron transport layers of either ZnO or ZnO/ZnS composite. The ZnO/ZnS composite can more efficiently quench the PL signal of perovskite absorber than bare ZnO resulting in enhanced photocurrent generation in PSCs.展开更多
The coupled nanocrystalline ZnO/ZnS was fabricated and immobilized in Nafion membrane by using sodium sulfide （Na2S） as the single anion precursor. The molar ratio of ZnO to ZnS can be controlled by simply adjusting...The coupled nanocrystalline ZnO/ZnS was fabricated and immobilized in Nafion membrane by using sodium sulfide （Na2S） as the single anion precursor. The molar ratio of ZnO to ZnS can be controlled by simply adjusting the reaction time. The as-prepared ZnO/ZnS-Nafion samples were characterized by various methods, including optical absorption, X-ray diffraction and high-resolution transmission electron microscopy. These coupled ZnO/ZnS nanocrystals embedded in Nafion membrane displayed excellent photocatalytic activities for their efficient charge separation properties. A mechanism of ZnO/ZnS nanoparticle fabrication in Nafion was deduced from the solubility difference, and the photocatalytic mechanism of coupled ZnO/ZnS was discussed as well.展开更多
The shuttle effect of polysulfides is one of the key factors hindering the commercialization of lithiumsulfur batteries(LSBs).Owing to their high conductivity and advantageous structure,heterostructures can be used in...The shuttle effect of polysulfides is one of the key factors hindering the commercialization of lithiumsulfur batteries(LSBs).Owing to their high conductivity and advantageous structure,heterostructures can be used in sulfur fixation and catalysis of LSBs.In this study,a flower-shaped ZnO/ZnS heterostructure on a nitrogendoped porous carbon(NPC) sulfur host was designed.The ZnO/ZnS heterostructure regulates the electronic structure of the material and exhibits higher metal-like properties.Moreover,the ZnO/ZnS heterostructure combines the strong adsorption property of ZnO and the high catalytic ability of ZnS to realize the anchoring-diffusionconversion of lithium poly sulfides(LiPSs).Results reveal that the developed ZnO/ZnS@NPC/S cathode has excellent electrochemical performance in LSBs,achieving a high discharge specific capacity of 1365.3 mAh·g^(-1) at 0.1C and excellent rate capability(719 mAh·g^(-1) at 2C;the capacity decay rate is only 0.042% per cycle after 1000 cycles).Even under a high sulfur loading-E/S(electrolyte/sulfur)ratio of 5.1 mg·cm^(-2)-6 μl·mg^(-1),a high specific capacity of 723.7 mAh·g^(-1) is maintained after 60 cycles.This study provides a new strategy for a multifunctional sulfur host that can effectively alleviate the shuttle effect of LiPSs and improve the utilization of sulfur active substances.展开更多
Photocatalytic CO_(2) reduction driven by solar light is a green approach that can decrease the greenhouse effect induced by high CO_(2) concentration in the atmosphere and generate carbon-based chemicals/fuels as wel...Photocatalytic CO_(2) reduction driven by solar light is a green approach that can decrease the greenhouse effect induced by high CO_(2) concentration in the atmosphere and generate carbon-based chemicals/fuels as well.In this paper,non-metal co-catalysts ZnO/ZnS type-II hetero-junction nanoparticles with a rough surface were prepared through a hydrothermal process.When used as a photocatalyst for CO_(2) reduction,the optimal one showed good cycle stability and a higher yield rate of 27.8µmol·g^(−1)·h^(−1) for CO_(2) conversion into CO.The outstanding catalytic activity originated from i)the rich interfaces between ZnO and ZnS in the nanoscale could significantly reduce the delivery path of carriers and improve the utilization efficiency of photo-excited electron/hole pairs and ii)enriched surface oxygen defects could supply much more reaction active sites for CO_(2) adsorption.展开更多
The photocatalytic performance of ZnO/ZnS hybrid nanocomposite was largely higher than that of the mere ZnO or ZnS nanoparticles,but the complicated procedure and misdistribution of final products limited its large-sc...The photocatalytic performance of ZnO/ZnS hybrid nanocomposite was largely higher than that of the mere ZnO or ZnS nanoparticles,but the complicated procedure and misdistribution of final products limited its large-scale productions.The exploration of a novel synthesis route of ZnO/ZnS hybrid photocatalysts with high catalytic performance is becoming a crucial step for the large-scale application of ZnO/ZnS hybrid photocatalytic technique.Preparation and characterization of nanosized ZnO/ZnS hybrid photocatalysts were studied in this paper.The photocatalysts were obtained via microwavehydrothermal crystallization with the help of sodium citrate.The products were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),particle size distribution(PSD),and Fourier transformed infrared spectroscopy(FT-IR).The results indicated that so-synthesized ZnO/ZnS samples consisted of the high pure cubic(sphalerite)ZnS and hexagonal ZnO nanocrystallines with a narrow particle size distribution.The possible formation mechanisms of ZnO/ZnS nanocrystallines were mainly attributed to the superficially protective effect of citrate.The photocatalytic experiments demonstrated that the ZnO/ZnS photocatalysts exhibited a higher catalytic activity for the degradation of acid fuchsine than other monocomponents.展开更多
文摘Designing a step-scheme(S-scheme)heterojunction photocatalyst with vacancy engineering is a reliable approach to achieve highly efficient photocatalytic H_(2)production activity.Herein,a hollow ZnO/ZnS S-scheme heterojunction with O and Zn vacancies(VO,Zn-ZnO/ZnS)is rationally constructed via ion-exchange and calcination treatments.In such a photocatalytic system,the hollow structure combined with the introduction of dual vacancies endows the adequate light absorption.Moreover,the O and Zn vacancies serve as the trapping sites for photo-induced electrons and holes,respectively,which are beneficial for promoting the photo-induced carrier separation.Meanwhile,the S-scheme charge transfer mechanism can not only improve the separation and transfer efficiencies of photo-induced carrier but also retain the strong redox capacity.As expected,the optimized VO,Zn-ZnO/ZnS heterojunction exhibits a superior photocatalytic H_(2) production rate of 160.91 mmol g^(-1)h^(-1),approximately 643.6 times and 214.5 times with respect to that obtained on pure ZnO and ZnS,respectively.Simultaneously,the experimental results and density functional theory calculations disclose that the photo-induced carrier transfer pathway follows the S-scheme heterojunction mechanism and the introduction of O and Zn vacancies reduces the surface reaction barrier.This work provides an innovative strategy of vacancy engineering in S-scheme heterojunction for solar-to-fuel energy conversion.
基金supported by the Natural Science Foundation of China (no. 11574111)the Natural Science Foundation of Jilin Province (no. 20160101303JC)+2 种基金supported by the 973 Program (2014CB643506)the Natural Science Foundation of China (no. 21221063)the Program for Chang Jiang Scholars and Innovative Research Team in University (no. IRT101713018)
文摘Electron transport layers （ETLs） in perovskite solar cells （PSCs） are a key factor to determine the photo- voltaic performance. Herein, we demonstrate preparation of ZnO/ZnS core-shell composites through di- rectly synthesizing ZnS on the ZnO nanoparticles in solution. We confirmed the formation of ZnO/ZnS core-shell composites by the uses of X-ray diffraction patterns and the Fourier transform infrared spec- troscopy. ZnO/ZnS composites exhibit much homogeneous surface morphology as compared with the bare ZnO as revealed in the scanning electronic microscopy. Moreover, the upper shift of conduction band level upon composition of the ZnO/ZnS film results in a better alignment of energy level, which facilitates cas- cade charge extraction and thus improves the current density of perovskite solar cell. The shift of conduc- tion band also improves the voltage of the PSCs. The photoluminescence （PL） spectroscopies measured in both steady and transient states were carried out to characterize the charge extraction at the interface between CH_3NH_3Pbl_3 and the electron transport layers of either ZnO or ZnO/ZnS composite. The ZnO/ZnS composite can more efficiently quench the PL signal of perovskite absorber than bare ZnO resulting in enhanced photocurrent generation in PSCs.
基金supported by the National Natural Science Foundation of China (Nos. 20473017, 20537010,and 20573020)the National Key Basic Research Special Foundation (2006CB708605, 2007CB613306)
文摘The coupled nanocrystalline ZnO/ZnS was fabricated and immobilized in Nafion membrane by using sodium sulfide （Na2S） as the single anion precursor. The molar ratio of ZnO to ZnS can be controlled by simply adjusting the reaction time. The as-prepared ZnO/ZnS-Nafion samples were characterized by various methods, including optical absorption, X-ray diffraction and high-resolution transmission electron microscopy. These coupled ZnO/ZnS nanocrystals embedded in Nafion membrane displayed excellent photocatalytic activities for their efficient charge separation properties. A mechanism of ZnO/ZnS nanoparticle fabrication in Nafion was deduced from the solubility difference, and the photocatalytic mechanism of coupled ZnO/ZnS was discussed as well.
基金financially supported by Yunnan Major Scientific and Technological Projects (No.202202AG050003)Yunnan Fundamental Research Projects (Nos.202101BE070001-018 and 202201AT070070)。
文摘The shuttle effect of polysulfides is one of the key factors hindering the commercialization of lithiumsulfur batteries(LSBs).Owing to their high conductivity and advantageous structure,heterostructures can be used in sulfur fixation and catalysis of LSBs.In this study,a flower-shaped ZnO/ZnS heterostructure on a nitrogendoped porous carbon(NPC) sulfur host was designed.The ZnO/ZnS heterostructure regulates the electronic structure of the material and exhibits higher metal-like properties.Moreover,the ZnO/ZnS heterostructure combines the strong adsorption property of ZnO and the high catalytic ability of ZnS to realize the anchoring-diffusionconversion of lithium poly sulfides(LiPSs).Results reveal that the developed ZnO/ZnS@NPC/S cathode has excellent electrochemical performance in LSBs,achieving a high discharge specific capacity of 1365.3 mAh·g^(-1) at 0.1C and excellent rate capability(719 mAh·g^(-1) at 2C;the capacity decay rate is only 0.042% per cycle after 1000 cycles).Even under a high sulfur loading-E/S(electrolyte/sulfur)ratio of 5.1 mg·cm^(-2)-6 μl·mg^(-1),a high specific capacity of 723.7 mAh·g^(-1) is maintained after 60 cycles.This study provides a new strategy for a multifunctional sulfur host that can effectively alleviate the shuttle effect of LiPSs and improve the utilization of sulfur active substances.
基金This work was supported by the Funding for School-level Research Projects of Yancheng Institute of Technology,China(Nos.xjr2021054,xjr2021056)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.23KJD540001).
文摘Photocatalytic CO_(2) reduction driven by solar light is a green approach that can decrease the greenhouse effect induced by high CO_(2) concentration in the atmosphere and generate carbon-based chemicals/fuels as well.In this paper,non-metal co-catalysts ZnO/ZnS type-II hetero-junction nanoparticles with a rough surface were prepared through a hydrothermal process.When used as a photocatalyst for CO_(2) reduction,the optimal one showed good cycle stability and a higher yield rate of 27.8µmol·g^(−1)·h^(−1) for CO_(2) conversion into CO.The outstanding catalytic activity originated from i)the rich interfaces between ZnO and ZnS in the nanoscale could significantly reduce the delivery path of carriers and improve the utilization efficiency of photo-excited electron/hole pairs and ii)enriched surface oxygen defects could supply much more reaction active sites for CO_(2) adsorption.
基金This work was supported by the National Natural Science Foundation of China(Grant No.20377034).
文摘The photocatalytic performance of ZnO/ZnS hybrid nanocomposite was largely higher than that of the mere ZnO or ZnS nanoparticles,but the complicated procedure and misdistribution of final products limited its large-scale productions.The exploration of a novel synthesis route of ZnO/ZnS hybrid photocatalysts with high catalytic performance is becoming a crucial step for the large-scale application of ZnO/ZnS hybrid photocatalytic technique.Preparation and characterization of nanosized ZnO/ZnS hybrid photocatalysts were studied in this paper.The photocatalysts were obtained via microwavehydrothermal crystallization with the help of sodium citrate.The products were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),particle size distribution(PSD),and Fourier transformed infrared spectroscopy(FT-IR).The results indicated that so-synthesized ZnO/ZnS samples consisted of the high pure cubic(sphalerite)ZnS and hexagonal ZnO nanocrystallines with a narrow particle size distribution.The possible formation mechanisms of ZnO/ZnS nanocrystallines were mainly attributed to the superficially protective effect of citrate.The photocatalytic experiments demonstrated that the ZnO/ZnS photocatalysts exhibited a higher catalytic activity for the degradation of acid fuchsine than other monocomponents.
