Sodium with low cost and high abundance is considered as a substitute element of lithium for batteries and supercapacitors,which need the appropriate host materials to accommodate the relatively large Na^(+) ions.Comp...Sodium with low cost and high abundance is considered as a substitute element of lithium for batteries and supercapacitors,which need the appropriate host materials to accommodate the relatively large Na^(+) ions.Compared to Li^(+) storage,Na^(+) storage makes higher demands on the structural optimization of perovskite bismuth ferrite(BiFeO_(3)).We propose a novel strategy of defect engineering on BiFeO_(3) through Na and V codoping for high-efficiency Na^(+) storage,to reveal the roles of oxygen vacancies and V ions played in the enhanced electrochemical energy storage performances of Na-ion capacitors.The formation of the oxygen vacancies in the Na and V codoped BiFeO_(3)(denoted as NV-BFO),is promoted by Na doping and suppressed by V doping,which can be demonstrated by XPS and EPR spectra.By the first-principles calculations,the oxygen vacancies and V ions in NV-BFO are confirmed to substantially lower the Na^(+)migration energy barriers through the space and electric field effects,to effectively promote the Na^(+) transport in the crystals.Electrochemical kinetic analysis of the NV-BFO//NV-BFO capacitors indicates the dominant capacitive-controlled capacity,which depends on fast Na^(+) deintercalation-intercalation process in the NV-BFO electrode.The NV-BFO//NV-BFO capacitors open up a new avenue for developing highperformance Na-ion capacitors.展开更多
印染废水中过高浓度的Al^(3+)不仅会破坏生态环境,而且还将危害人类健康。因此,对印染废水中Al^(3+)浓度的精准检测具有十分重要的研究意义。本文以罗丹明B、乙二胺和4-甲酰基-3-羟基苯甲酸为原料,合成了新型荧光探针RhB-AC,并利用高分...印染废水中过高浓度的Al^(3+)不仅会破坏生态环境,而且还将危害人类健康。因此,对印染废水中Al^(3+)浓度的精准检测具有十分重要的研究意义。本文以罗丹明B、乙二胺和4-甲酰基-3-羟基苯甲酸为原料,合成了新型荧光探针RhB-AC,并利用高分辨质谱(HRMS)及核磁共振氢谱(1H NMR)对探针RhB-AC的分子结构进行了表征。探针RhB-AC在水中,由于光诱导的电子转移(Photoinduced electron transfer,PET)效应,其荧光发生猝灭。当与Al^(3+)作用后,PET效应被抑制,探针表现出很强的青绿色荧光。另外,该探针对Al^(3+)检测的速度快(3秒以内)、选择性好、灵敏度高(检测限为16 nM)。最后,该探针还能快速、定量检测实际印染废水中的Al^(3+)浓度。展开更多
The activation of H_(2)O is a key step of the COS hydrolysis,which may be tuned by oxygen vacancy defects in the catalysts.Herein,we have introduced Cu into Co_(3)O_(4) to regulate the oxygen vacancy defect content of...The activation of H_(2)O is a key step of the COS hydrolysis,which may be tuned by oxygen vacancy defects in the catalysts.Herein,we have introduced Cu into Co_(3)O_(4) to regulate the oxygen vacancy defect content of the catalysts.In situ DRIFTS and XPS spectra reveal that COS and H_(2)O are adsorbed and activated by oxygen vacancy.The 10 at%Cu doped Co_(3)O_(4) sample(10Cu-Co_(3)O_(4))exhibits the optimal activity,100%of COS conversion at 70℃.The improved oxygen vacancies of CueCo_(3)O_(4) accelerate the activation of H_(2)O to form active -OH.COS binds with hydroxyl to form the intermediate HSCO^(-)_(2),and then the activated-OH on the oxygen vacancy reacts with HSCO^(-)_(2) to form HCO^(-)_(3).Meanwhile,the catalyst exhibits high catalytic stability because copper species(Cu+/Cu^(2+))redox cycle mitigate the sulfation of Co_(3)O_(4)(Co^(2+)/Co^(3+)).Our work offers a promising approach for the rational design of cobalt-related catalysts in the highly efficient hydrolysis COS process.展开更多
基金financial supports from National Natural Science Foundation of China(22005174 and 52271133)。
文摘Sodium with low cost and high abundance is considered as a substitute element of lithium for batteries and supercapacitors,which need the appropriate host materials to accommodate the relatively large Na^(+) ions.Compared to Li^(+) storage,Na^(+) storage makes higher demands on the structural optimization of perovskite bismuth ferrite(BiFeO_(3)).We propose a novel strategy of defect engineering on BiFeO_(3) through Na and V codoping for high-efficiency Na^(+) storage,to reveal the roles of oxygen vacancies and V ions played in the enhanced electrochemical energy storage performances of Na-ion capacitors.The formation of the oxygen vacancies in the Na and V codoped BiFeO_(3)(denoted as NV-BFO),is promoted by Na doping and suppressed by V doping,which can be demonstrated by XPS and EPR spectra.By the first-principles calculations,the oxygen vacancies and V ions in NV-BFO are confirmed to substantially lower the Na^(+)migration energy barriers through the space and electric field effects,to effectively promote the Na^(+) transport in the crystals.Electrochemical kinetic analysis of the NV-BFO//NV-BFO capacitors indicates the dominant capacitive-controlled capacity,which depends on fast Na^(+) deintercalation-intercalation process in the NV-BFO electrode.The NV-BFO//NV-BFO capacitors open up a new avenue for developing highperformance Na-ion capacitors.
文摘印染废水中过高浓度的Al^(3+)不仅会破坏生态环境,而且还将危害人类健康。因此,对印染废水中Al^(3+)浓度的精准检测具有十分重要的研究意义。本文以罗丹明B、乙二胺和4-甲酰基-3-羟基苯甲酸为原料,合成了新型荧光探针RhB-AC,并利用高分辨质谱(HRMS)及核磁共振氢谱(1H NMR)对探针RhB-AC的分子结构进行了表征。探针RhB-AC在水中,由于光诱导的电子转移(Photoinduced electron transfer,PET)效应,其荧光发生猝灭。当与Al^(3+)作用后,PET效应被抑制,探针表现出很强的青绿色荧光。另外,该探针对Al^(3+)检测的速度快(3秒以内)、选择性好、灵敏度高(检测限为16 nM)。最后,该探针还能快速、定量检测实际印染废水中的Al^(3+)浓度。
基金the National Natural Science Foundation of China (92034301,22078063 and 22022804)Major Program of Qingyuan Innovation Laboratory (00121003)the Natural Science Foundation of Fujian Province (2020H6007)。
文摘The activation of H_(2)O is a key step of the COS hydrolysis,which may be tuned by oxygen vacancy defects in the catalysts.Herein,we have introduced Cu into Co_(3)O_(4) to regulate the oxygen vacancy defect content of the catalysts.In situ DRIFTS and XPS spectra reveal that COS and H_(2)O are adsorbed and activated by oxygen vacancy.The 10 at%Cu doped Co_(3)O_(4) sample(10Cu-Co_(3)O_(4))exhibits the optimal activity,100%of COS conversion at 70℃.The improved oxygen vacancies of CueCo_(3)O_(4) accelerate the activation of H_(2)O to form active -OH.COS binds with hydroxyl to form the intermediate HSCO^(-)_(2),and then the activated-OH on the oxygen vacancy reacts with HSCO^(-)_(2) to form HCO^(-)_(3).Meanwhile,the catalyst exhibits high catalytic stability because copper species(Cu+/Cu^(2+))redox cycle mitigate the sulfation of Co_(3)O_(4)(Co^(2+)/Co^(3+)).Our work offers a promising approach for the rational design of cobalt-related catalysts in the highly efficient hydrolysis COS process.
