Stable and high‐efficiency bifunctional catalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desired for the practical application of Li‐O_(2)batteries with excellent rate performanc...Stable and high‐efficiency bifunctional catalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desired for the practical application of Li‐O_(2)batteries with excellent rate performance and cycle stability.Herein,a novel hybrid bifunctional catalyst with carbon nanofibers inlaid with hollow Co_(3)O_(4)nanoparticles and separate active sites for ORR and OER were prepared and applied in Li‐O_(2)batteries.Benefiting from the synergistic effect of unique porous structural features and high electrocatalytic activity of hollow Co3O4 intimately bound to N‐doped carbon nanofibers,the assembled Li‐O_(2)batteries with novel catalyst exhibited high specific capacity,excellent rate capability,and cycle stability up to 150 cycles under a capacity limitation of 500 mAh g^(–1)at a current density of 100 mA g^(–1).The facile synthesis and preliminary results in this work show the as‐prepared catalyst as a promising bifunctional electrocatalyst for applications in metal‐air batteries,fuel cells,and electrocatalysis.展开更多
Developing high efficient Pd-based electrocatalysts for oxygen reduction reaction(ORR) is still challenging for alkaline membrane fuel cell,since the strong oxygen adsorption energy and easy agglomerative intrinsic pr...Developing high efficient Pd-based electrocatalysts for oxygen reduction reaction(ORR) is still challenging for alkaline membrane fuel cell,since the strong oxygen adsorption energy and easy agglomerative intrinsic properties. In order to simultaneously solve these problems, Pd/Co_(3)O_(4)–N–C multidimensional materials with porous structures is designed as the ORR catalysts. In details, the ZIF-67 with polyhedral structure was firstly synthesized and then annealed at high-temperature to prepare the N-doped Co_(3)O_(4)carbon-based material, which was used to homogeneously confine Pd nanoparticles and obtained the Pd/Co_(3)O_(4)–N–C series catalysts. The formation of Co–N and C–N bond could provide efficient active sites for ORR. Simultaneously, the strong electronic interaction in the interface between the Pd and N-doped Co_(3)O_(4)could disperse and avoid the agglomeration of Pd nanoparticles and ensure the exposure of active sites, which is crucial to lower the energy barrier toward ORR and substantially enhance the ORR kinetics. Hence, the Pd/Co_(3)O_(4)–N–C nanocompounds exhibited excellent ORR catalytic performance, ideal Pd mass activity, and durability in 0.1 mol L-1KOH solution compared with Co_(3)O_(4)–N–C and Pd/C. The scalable synthesis method, relatively low cost, and excellent electrochemical ORR performance indicated that the obtained Pd/Co_(3)O_(4)–N–C electrocatalyst had the potential for application on fuel cells.展开更多
At present,the high re-combination rate of photogenerated carriers and the low redox capability of the photocatalyst are two factors that severely limit the improvement of photocatalytic performance.Herein,a dual Z-sc...At present,the high re-combination rate of photogenerated carriers and the low redox capability of the photocatalyst are two factors that severely limit the improvement of photocatalytic performance.Herein,a dual Z-scheme photocatalyst bismuthzirconate/graphitic carbon nitride/silver phosphate (Bi_(2)Zr_(2)O_(7)/g-C_(3)N4/Ag_(3)PO_(4)(BCA)) was synthesized using a co-precipitation method,and a dual Z-scheme heterojunction photocatalytic system was established to decrease the high re-combination rate of photogenerated carriers and consequently improve the photocatalytic performance.The re-combination of electron-hole pairs(e-and h+) in the valence band (VB) of g-C_(3)N4increases the redox potential of e-and h+,leading to significant improvements in the redox capability of the photocatalyst and the efficiency of e--h+separation.As a photosensitizer,Ag_(3)PO_(4)can enhance the visible light absorption capacity of the photocatalyst.The prepared photocatalyst showed strong stability,which was attributed to the efficient suppression of photo-corrosion of Ag_(3)PO_(4)by transferring the e-to the VB of g-C_(3)N4.Tetracycline was degraded efficiently by BCA-10%(the BCA with 10 wt.%of AgPO_(4)) under visible light,and the degradation efficiency was up to 86.2%.This study experimentally suggested that the BCA photocatalyst has broad application prospects in removing antibiotic pollution.展开更多
Driven by safety issues,environmental concerns,and high costs,rechargeable aqueous zinc-ion batteries(ZIBs)have received increasing attention in recent years owing to their unique advantages.However,the sluggish kinet...Driven by safety issues,environmental concerns,and high costs,rechargeable aqueous zinc-ion batteries(ZIBs)have received increasing attention in recent years owing to their unique advantages.However,the sluggish kinetics of divalent charge Zn^(2+)in the cathode materials caused by the strong electrostatic interaction and their unsatisfactory cycle life hinder the development of ZIBs.Herein,organic cations and Zn^(2+)ions co-pre-inserted vanadium oxide([N(CH_(3))_(4)]_(0.77),Zn_(0.23))V_(8)O_(20)·3.8H_(2)O are reported as the cathode for ultra-stable aqueous ZIBs,in which the weaker electrostatic interactions between Zn^(2+)and organic ion-pinned vanadium oxide can induce the high reversibility of Zn^(2+)insertion and extraction,thereby improving the cycle life.It is demonstrated that([N(CH_(3))_(4)]_(0.77),Zn_(0.23))V_(8)O_(20)·3.8H_(2)O cathodes deliver a discharge capacity of 181 mA h g^(-1)at8 A g^(-1)and ultra-long life span(99.5%capacity retention after 2000 cycles).A reversible Zn^(2+)/H^(+)ions(de)intercalation storage process and pseudocapacitive charge storage are characterized.The weaker interactions between organic ion and Zn^(2+)open a novel avenue for the design of highly reversible cathode materials with long-term cycling stability.展开更多
Enhancement of supercapacitors(SCs)with high-energy density and high-power density is still a great challenge.In this paper,a facile strategy for in situ anchoring of Co_(3)O_(4) particles on N doped carbon cloth(pCoN...Enhancement of supercapacitors(SCs)with high-energy density and high-power density is still a great challenge.In this paper,a facile strategy for in situ anchoring of Co_(3)O_(4) particles on N doped carbon cloth(pCoNCC)is reported.Due to the interaction of the doped N and Co_(3)O_(4),the electrochemical performance improves significantly,reaching 1,940.13 mF·cm^(−2) at 1 mA·cm^(−2) and energy density of 172.46μWh·cm^(−2) at the power density of 400μW·cm^(−2),much larger than that without N doping electrode of 28.5 mF·cm^(−2).An aqueous symmetric supercapacitor(ASSC)assembled by two pCoNCC electrodes achieves a maximum energy density of 447.42μWh·cm^(−2) and a highest power density of 8,000μW·cm^(−2).Utilizing such a high-energy storage ASSC,a digital watch and a temperature-humidity detector are powered for nearly 1 and 2 h,respectively.Moreover,the ASSC displays a superb electrochemical stability of 87.7%retention after 10,000 cycles at 40 mA·cm^(−2).This work would provide a new sight to enhance active materials performance and be beneficial for the future energy storage and supply systems.展开更多
文摘Stable and high‐efficiency bifunctional catalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desired for the practical application of Li‐O_(2)batteries with excellent rate performance and cycle stability.Herein,a novel hybrid bifunctional catalyst with carbon nanofibers inlaid with hollow Co_(3)O_(4)nanoparticles and separate active sites for ORR and OER were prepared and applied in Li‐O_(2)batteries.Benefiting from the synergistic effect of unique porous structural features and high electrocatalytic activity of hollow Co3O4 intimately bound to N‐doped carbon nanofibers,the assembled Li‐O_(2)batteries with novel catalyst exhibited high specific capacity,excellent rate capability,and cycle stability up to 150 cycles under a capacity limitation of 500 mAh g^(–1)at a current density of 100 mA g^(–1).The facile synthesis and preliminary results in this work show the as‐prepared catalyst as a promising bifunctional electrocatalyst for applications in metal‐air batteries,fuel cells,and electrocatalysis.
基金funded by National Natural Science Foundation of China (21975129)Natural Science Foundation of Jiangsu Province (BK20190759)+1 种基金Nanjing Forestry UniversityPostgraduate Research & Practice Innovation Program of Jiangsu Province (SJCX21_0337)。
文摘Developing high efficient Pd-based electrocatalysts for oxygen reduction reaction(ORR) is still challenging for alkaline membrane fuel cell,since the strong oxygen adsorption energy and easy agglomerative intrinsic properties. In order to simultaneously solve these problems, Pd/Co_(3)O_(4)–N–C multidimensional materials with porous structures is designed as the ORR catalysts. In details, the ZIF-67 with polyhedral structure was firstly synthesized and then annealed at high-temperature to prepare the N-doped Co_(3)O_(4)carbon-based material, which was used to homogeneously confine Pd nanoparticles and obtained the Pd/Co_(3)O_(4)–N–C series catalysts. The formation of Co–N and C–N bond could provide efficient active sites for ORR. Simultaneously, the strong electronic interaction in the interface between the Pd and N-doped Co_(3)O_(4)could disperse and avoid the agglomeration of Pd nanoparticles and ensure the exposure of active sites, which is crucial to lower the energy barrier toward ORR and substantially enhance the ORR kinetics. Hence, the Pd/Co_(3)O_(4)–N–C nanocompounds exhibited excellent ORR catalytic performance, ideal Pd mass activity, and durability in 0.1 mol L-1KOH solution compared with Co_(3)O_(4)–N–C and Pd/C. The scalable synthesis method, relatively low cost, and excellent electrochemical ORR performance indicated that the obtained Pd/Co_(3)O_(4)–N–C electrocatalyst had the potential for application on fuel cells.
基金the financial support provided by the Shandong University Cross Project fund (No.2016JC003)。
文摘At present,the high re-combination rate of photogenerated carriers and the low redox capability of the photocatalyst are two factors that severely limit the improvement of photocatalytic performance.Herein,a dual Z-scheme photocatalyst bismuthzirconate/graphitic carbon nitride/silver phosphate (Bi_(2)Zr_(2)O_(7)/g-C_(3)N4/Ag_(3)PO_(4)(BCA)) was synthesized using a co-precipitation method,and a dual Z-scheme heterojunction photocatalytic system was established to decrease the high re-combination rate of photogenerated carriers and consequently improve the photocatalytic performance.The re-combination of electron-hole pairs(e-and h+) in the valence band (VB) of g-C_(3)N4increases the redox potential of e-and h+,leading to significant improvements in the redox capability of the photocatalyst and the efficiency of e--h+separation.As a photosensitizer,Ag_(3)PO_(4)can enhance the visible light absorption capacity of the photocatalyst.The prepared photocatalyst showed strong stability,which was attributed to the efficient suppression of photo-corrosion of Ag_(3)PO_(4)by transferring the e-to the VB of g-C_(3)N4.Tetracycline was degraded efficiently by BCA-10%(the BCA with 10 wt.%of AgPO_(4)) under visible light,and the degradation efficiency was up to 86.2%.This study experimentally suggested that the BCA photocatalyst has broad application prospects in removing antibiotic pollution.
基金supported by the funding from the National Natural Science Foundation of China(grant nos.51902187,52072224,and 51732007)the Natural Science Foundation of Shandong Province(ZR2018BEM010)+3 种基金the Science Fund for Distinguished Young Scholars of Shandong Province(ZR2019JQ16)the Fundamental Research Funds of Shandong UniversityYoung Elite Scientist Sponsorship Program by CAST(YESS)the support from Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong
文摘Driven by safety issues,environmental concerns,and high costs,rechargeable aqueous zinc-ion batteries(ZIBs)have received increasing attention in recent years owing to their unique advantages.However,the sluggish kinetics of divalent charge Zn^(2+)in the cathode materials caused by the strong electrostatic interaction and their unsatisfactory cycle life hinder the development of ZIBs.Herein,organic cations and Zn^(2+)ions co-pre-inserted vanadium oxide([N(CH_(3))_(4)]_(0.77),Zn_(0.23))V_(8)O_(20)·3.8H_(2)O are reported as the cathode for ultra-stable aqueous ZIBs,in which the weaker electrostatic interactions between Zn^(2+)and organic ion-pinned vanadium oxide can induce the high reversibility of Zn^(2+)insertion and extraction,thereby improving the cycle life.It is demonstrated that([N(CH_(3))_(4)]_(0.77),Zn_(0.23))V_(8)O_(20)·3.8H_(2)O cathodes deliver a discharge capacity of 181 mA h g^(-1)at8 A g^(-1)and ultra-long life span(99.5%capacity retention after 2000 cycles).A reversible Zn^(2+)/H^(+)ions(de)intercalation storage process and pseudocapacitive charge storage are characterized.The weaker interactions between organic ion and Zn^(2+)open a novel avenue for the design of highly reversible cathode materials with long-term cycling stability.
基金This work was supported by the National Natural Science Foundation of China(Nos.51772036 and 51572040)the Fundamental Research Funds for the Central Universities(Nos.2019CDXZWL001 and 2020CDCGJ005).
文摘Enhancement of supercapacitors(SCs)with high-energy density and high-power density is still a great challenge.In this paper,a facile strategy for in situ anchoring of Co_(3)O_(4) particles on N doped carbon cloth(pCoNCC)is reported.Due to the interaction of the doped N and Co_(3)O_(4),the electrochemical performance improves significantly,reaching 1,940.13 mF·cm^(−2) at 1 mA·cm^(−2) and energy density of 172.46μWh·cm^(−2) at the power density of 400μW·cm^(−2),much larger than that without N doping electrode of 28.5 mF·cm^(−2).An aqueous symmetric supercapacitor(ASSC)assembled by two pCoNCC electrodes achieves a maximum energy density of 447.42μWh·cm^(−2) and a highest power density of 8,000μW·cm^(−2).Utilizing such a high-energy storage ASSC,a digital watch and a temperature-humidity detector are powered for nearly 1 and 2 h,respectively.Moreover,the ASSC displays a superb electrochemical stability of 87.7%retention after 10,000 cycles at 40 mA·cm^(−2).This work would provide a new sight to enhance active materials performance and be beneficial for the future energy storage and supply systems.
