Mg基制氢材料具有来源广泛、反应温和、工艺简单、安全可控、理论产氢量高等优势,是当今的研究热点.本文提出采用高能球磨方法制备Mg-Bi系含氧酸盐Bi_(x)M_(y)O_(z)(M=Ti,V,Cr,Mo,W)复合材料以改善Mg水解制氢性能.本工作研究发现,掺杂Bi...Mg基制氢材料具有来源广泛、反应温和、工艺简单、安全可控、理论产氢量高等优势,是当今的研究热点.本文提出采用高能球磨方法制备Mg-Bi系含氧酸盐Bi_(x)M_(y)O_(z)(M=Ti,V,Cr,Mo,W)复合材料以改善Mg水解制氢性能.本工作研究发现,掺杂Bi_(2)Mo O_(6)的Mg基复合制氢材料具有较好的性能,Mg-7 wt%Bi_(2)Mo O_(6)在298.15 K的最大产氢速率为756.1 m L g^(-1)min(-1).通过引入多壁碳纳米管(CNTs)可以进一步改善Mg-Bi_(2)Mo O_(6)的产氢性能,Mg-7 wt%Bi_(2)Mo O_(6)/CNTs的最大产氢速率达2172.4 m L g^(-1)min(-1),产氢活化能下降至23.6 k J mol^(-1).X光电子能谱(XPS)分析表明Bi_(2)Mo O_(6)/CNTs与Mg在球磨过程中发生固相反应生成Bi单质.密度泛函理论(DFT)计算揭示Bi原子掺杂可改变Mg的局域电荷分布,增强Mg对H_(2)O的吸附能,并降低H_(2)O解离后H原子的吸附能,促进水解反应进行.展开更多
Van der Waals(VDW)heterostructures have attracted significant research interest due to their tunable interfacial properties and potential applications in many areas such as electronics,optoelectronic,and heterocatalys...Van der Waals(VDW)heterostructures have attracted significant research interest due to their tunable interfacial properties and potential applications in many areas such as electronics,optoelectronic,and heterocatalysis.In this work,the influences of interfacial defects on the electronic structures and photocatalytic properties of hBN/MX_(2)(M=Mo,W,and X=S,Se)are studied using density functional theory calculations.The results reveal that the band alignment of hBN/MX_(2) can be adjusted by introducing vacancies and atomic doping.The type-Ⅰband alignment of the host structure is maintained in the heterostructure with n-type doping in the hBN sublayer.Interestingly,the band alignment changed into the type-Ⅱheterostructrue due to V_(B) defect and p-type doping is introduced into the hBN sublayer.This can conduce to the separation of photo-generated electron-hole pairs at the interfaces,which is highly desired for heterostructure photocatalysis.In addition,two Z-type heterostructures including h BN(BeB)/MoS_(2),hBN(Be_(B))/MoSe_(2),and hBN(V_(N))/MoSe_(2)are achieved,showing the decreasing of band gap and ideal redox potential for water splitting.Our results reveal the possibility of engineering the interfacial and photocatalysis properties of hBN/MX_(2) heterostructures via interfacial defects.展开更多
文摘Mg基制氢材料具有来源广泛、反应温和、工艺简单、安全可控、理论产氢量高等优势,是当今的研究热点.本文提出采用高能球磨方法制备Mg-Bi系含氧酸盐Bi_(x)M_(y)O_(z)(M=Ti,V,Cr,Mo,W)复合材料以改善Mg水解制氢性能.本工作研究发现,掺杂Bi_(2)Mo O_(6)的Mg基复合制氢材料具有较好的性能,Mg-7 wt%Bi_(2)Mo O_(6)在298.15 K的最大产氢速率为756.1 m L g^(-1)min(-1).通过引入多壁碳纳米管(CNTs)可以进一步改善Mg-Bi_(2)Mo O_(6)的产氢性能,Mg-7 wt%Bi_(2)Mo O_(6)/CNTs的最大产氢速率达2172.4 m L g^(-1)min(-1),产氢活化能下降至23.6 k J mol^(-1).X光电子能谱(XPS)分析表明Bi_(2)Mo O_(6)/CNTs与Mg在球磨过程中发生固相反应生成Bi单质.密度泛函理论(DFT)计算揭示Bi原子掺杂可改变Mg的局域电荷分布,增强Mg对H_(2)O的吸附能,并降低H_(2)O解离后H原子的吸附能,促进水解反应进行.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB3802400)the National Natural Science Foundation of China(Grant Nos.52161037,U20A20237,51871065,and 51971068)+4 种基金the Scientific Research and Technology Development Program of Guangxi Zhuang Autonmous Region Province,China(Grant Nos.AD19110037,AA19182014,AD17195073,and AA17202030-1)the Guangxi Natural Science Foundation,China(Grant Nos.2017JJB150085 and 2019GXNSFGA245005)the Innovation Project of GUET Graduate Education,China(Grant No.2022YCXS197)the Guangxi Bagui Scholar Foundation,Guangxi Collaborative Innovation Centre of Structure and Property for New Energy and Materials,Guangxi Advanced Functional Materials Foundation and Application Talents Small Highlands,ChinesischDeutsche Kooperationsgruppe,China(Grant No.GZ1528)the Guangxi Key Laboratory of Information Material,China(Grant No.201025-Z)。
文摘Van der Waals(VDW)heterostructures have attracted significant research interest due to their tunable interfacial properties and potential applications in many areas such as electronics,optoelectronic,and heterocatalysis.In this work,the influences of interfacial defects on the electronic structures and photocatalytic properties of hBN/MX_(2)(M=Mo,W,and X=S,Se)are studied using density functional theory calculations.The results reveal that the band alignment of hBN/MX_(2) can be adjusted by introducing vacancies and atomic doping.The type-Ⅰband alignment of the host structure is maintained in the heterostructure with n-type doping in the hBN sublayer.Interestingly,the band alignment changed into the type-Ⅱheterostructrue due to V_(B) defect and p-type doping is introduced into the hBN sublayer.This can conduce to the separation of photo-generated electron-hole pairs at the interfaces,which is highly desired for heterostructure photocatalysis.In addition,two Z-type heterostructures including h BN(BeB)/MoS_(2),hBN(Be_(B))/MoSe_(2),and hBN(V_(N))/MoSe_(2)are achieved,showing the decreasing of band gap and ideal redox potential for water splitting.Our results reveal the possibility of engineering the interfacial and photocatalysis properties of hBN/MX_(2) heterostructures via interfacial defects.
