In the present work,hierarchical nanostructured titanium dioxide(TiO2) films were fabricated on Ti-25Nb-3Mo-2Sn-3Zr(TLM) alloy for biomedical applications via one-step anodization process in ethylene glycolbased elect...In the present work,hierarchical nanostructured titanium dioxide(TiO2) films were fabricated on Ti-25Nb-3Mo-2Sn-3Zr(TLM) alloy for biomedical applications via one-step anodization process in ethylene glycolbased electrolyte containing 0.5wt% NH4F.The nanostructured TiO2 films exhibited three distinct types depending on the anodization time:top irregular nanopores(INP)/beneath regular nanopores(RNP),top INP/middle regular nanotubes(RNT)/bottom RNP and top RNT with underlying RNP.The evolution of the nanostructured TiO2 films with anodization time demonstrated that self-organizing nanopores formed at the very beginning and individual nanotubes originated from underlying nanopore dissolution.Furthermore,a modified two-stage self-organizing mechanism was introduced to illustrate the growth of the nanostructured TiO2 films.Compared with TLM titanium alloy matrix,the TiO2 films with special nano-structure hold better hydrophilicity and higher specific surface area,which lays the foundation for their biomedical applications.展开更多
Developing efficient platinum(Pt)-based electrocatalysts is enormously significant for fuel cells.Herein,we report an integrated electrocatalyst of ultralow-Pt alloy encapsulated into nitrogen-doped nanocarbon archite...Developing efficient platinum(Pt)-based electrocatalysts is enormously significant for fuel cells.Herein,we report an integrated electrocatalyst of ultralow-Pt alloy encapsulated into nitrogen-doped nanocarbon architecture for efficient oxygen reduction reaction.This hybrid Pt-based catalyst achieves a mass activity of 3.46 A mg^(-1)_(pt)the potential of 0.9 V vs.RHE with a negligible stability decay after 10,000 cycles.More importantly,this half-cell activity can be expressed at full cell level with a high Pt utilization of 10.22 W mg^(-1)_(Pt cathode)and remarkable durability after 30,000 cycles in single-cell.Experimental and theoretical investigations reveal that a highly strained Pt structure with an optimal Pt-0 binding energy is induced by the incorporation of Co/Ni into Pt lattice,which would account for the improved reaction kinetics.The synergistic catalysis due to nitrogen-doped nanocarbon architecture and active Pt component is responsible for the enhanced catalytic activity.Meanwhile,the strong metal-support interaction and optimized hydrophilic properties of nanocarbon matrix facilitate efficient mass transport and water management.This work may provide significant insights in designing the low-Pt integrated electrocatalysts for fuel cells and beyond.展开更多
基金Supported by the National Natural Science Foundation of China(No.51372169)Natural Science Foundation of Tianjin(No.11JCZDJC17300)
文摘In the present work,hierarchical nanostructured titanium dioxide(TiO2) films were fabricated on Ti-25Nb-3Mo-2Sn-3Zr(TLM) alloy for biomedical applications via one-step anodization process in ethylene glycolbased electrolyte containing 0.5wt% NH4F.The nanostructured TiO2 films exhibited three distinct types depending on the anodization time:top irregular nanopores(INP)/beneath regular nanopores(RNP),top INP/middle regular nanotubes(RNT)/bottom RNP and top RNT with underlying RNP.The evolution of the nanostructured TiO2 films with anodization time demonstrated that self-organizing nanopores formed at the very beginning and individual nanotubes originated from underlying nanopore dissolution.Furthermore,a modified two-stage self-organizing mechanism was introduced to illustrate the growth of the nanostructured TiO2 films.Compared with TLM titanium alloy matrix,the TiO2 films with special nano-structure hold better hydrophilicity and higher specific surface area,which lays the foundation for their biomedical applications.
基金the National Natural Science Foundation of China(22075092 and 21805104)the Program for Huazhong University of Science and Technology(HUST)Academic Frontier Youth Team(2018QYTD15)The Innovation and Talent Recruitment Base of New Energy Chemistry and Device(B21003)。
文摘Developing efficient platinum(Pt)-based electrocatalysts is enormously significant for fuel cells.Herein,we report an integrated electrocatalyst of ultralow-Pt alloy encapsulated into nitrogen-doped nanocarbon architecture for efficient oxygen reduction reaction.This hybrid Pt-based catalyst achieves a mass activity of 3.46 A mg^(-1)_(pt)the potential of 0.9 V vs.RHE with a negligible stability decay after 10,000 cycles.More importantly,this half-cell activity can be expressed at full cell level with a high Pt utilization of 10.22 W mg^(-1)_(Pt cathode)and remarkable durability after 30,000 cycles in single-cell.Experimental and theoretical investigations reveal that a highly strained Pt structure with an optimal Pt-0 binding energy is induced by the incorporation of Co/Ni into Pt lattice,which would account for the improved reaction kinetics.The synergistic catalysis due to nitrogen-doped nanocarbon architecture and active Pt component is responsible for the enhanced catalytic activity.Meanwhile,the strong metal-support interaction and optimized hydrophilic properties of nanocarbon matrix facilitate efficient mass transport and water management.This work may provide significant insights in designing the low-Pt integrated electrocatalysts for fuel cells and beyond.
