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
以ZnCl_(2)为硬模板和锌源,三聚氰胺和硫脲为氮源和硫源,废弃生物质橘子皮为碳源,通过高温烧结和后续蚀刻处理制备出硫化锌纳米点与三维N-S共掺杂炭纳米片的纳米复合材料(ZnS/NS-CN)。当应用于锂离子电池时,ZnS/NSCN表现出较高的可逆容...以ZnCl_(2)为硬模板和锌源,三聚氰胺和硫脲为氮源和硫源,废弃生物质橘子皮为碳源,通过高温烧结和后续蚀刻处理制备出硫化锌纳米点与三维N-S共掺杂炭纳米片的纳米复合材料(ZnS/NS-CN)。当应用于锂离子电池时,ZnS/NSCN表现出较高的可逆容量(0.1 A g^(−1)下,循环300次后容量仍有853.5 mAh g^(−1)),优异的长期循环稳定性(5 A g^(−1)下,循环1000次后,容量保持率为70.1%)和优异的倍率性能。此外,在0.5~4 V下组装和测试的ZnS/NS-CN//LiNiCoMnO2全电池表现出优异的电池性能(在0.2 C下循环150次后容量为140.4 mAh g^(−1),能量密度为132.4 Wh kg^(−1))。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.
文摘纳米技术研究体系中量子点是重要的研究模块之一,量子点尺寸非常小,具有独特的光物理特性。该文旨通过实验进行分析,实验过程选择99%纯度硼氢化钠、99%纯度硫酸锌、S212恒速搅拌器、TG16-WS高速离心机、0.310 mL巯基乙酸等,制备0.4565 g CdCl_(2)·2.5H_(2)O混合液,当样本溶液呈现橙色时,表明CdTe核已制备完成。实验结果显示:单脉冲能量增加时,τ_(-rise)与τ_(2)有所降低,τ_(1)数值增加,τ_(-rise)与壳层厚度呈正比关系。通过对量子点荧光特性的分析,有利于促进核壳结构量子点的制备。
文摘以ZnCl_(2)为硬模板和锌源,三聚氰胺和硫脲为氮源和硫源,废弃生物质橘子皮为碳源,通过高温烧结和后续蚀刻处理制备出硫化锌纳米点与三维N-S共掺杂炭纳米片的纳米复合材料(ZnS/NS-CN)。当应用于锂离子电池时,ZnS/NSCN表现出较高的可逆容量(0.1 A g^(−1)下,循环300次后容量仍有853.5 mAh g^(−1)),优异的长期循环稳定性(5 A g^(−1)下,循环1000次后,容量保持率为70.1%)和优异的倍率性能。此外,在0.5~4 V下组装和测试的ZnS/NS-CN//LiNiCoMnO2全电池表现出优异的电池性能(在0.2 C下循环150次后容量为140.4 mAh g^(−1),能量密度为132.4 Wh kg^(−1))。
