Design Of Transition Metal-Based Nanoelectrocatalyst And Their Electrocatalytic Applications

Transition metal-based nanomaterials are favored as electrocatalysts in the fields of electrocatalytic sensing detection and metal-air batteries due to their unique advantages.Contemporary society pays close attention to the issue of human health monitoring and the development of storage and conversion devices for green and sustainable energy.Diabetes and cancer are two major diseases threatening human health,and their typical diagnostic markers are the levels of small molecules glucose and hydrogen peroxide(H2O2),respectively.The solution to this challenge is to construct an efficient,specific and stable glucose and H2O2 sensing and detection platform.In addition,the development of renewable zinc-air batteries with high efficiency and excellent durability is crucial for alleviating energy depletion and environmental pollution.Electrode materials are the crucial components of the small molecule sensing platform and zinc-air battery.By rationally combining with various strategies to design and regulate highly active catalyst as electrode materials,the above two health and energy requirements can be satisfied.These strategies involve morphological component engineering(including hollow structure,porous structure,and self-supporting electrodes),doping engineering,defect engineering,interface engineering,synergistic effects and enhancing conductivity.This paper mainly based on these above design strategies to develop high-performance and robust electrocatalysts for electrochemical non-enzymatic detection of glucose and H2O2,ORR/OER and zinc-air batteries.With the hope that it has potential to alleviate the current medical diagnostics and energy difficulties.This paper mainly includes four parts as follows:1.The combinations of transition metal oxides with porous hollow architectures open new avenues in designing sensing material with outstanding performances.A bifunctional catalyst of CuO/NiOx/y nanocomposite was developed for electrocatalytic oxidation of glucose and reduction of H2O2 by the simple solvothermal and thermal treatment process.The structures can be controlled facilely by adjusting the amounts of NiCl2,and the architectures of core-shell,yolk-shell and hollow can be acquired.The electrochemical results demonstrate that the porous hollow structure(CuO/NiO30/90)exhibited the best electrocatalytic activity towards glucose oxidation in alkaline solution.Meanwhile,it also displayed good electrocatalytic activity towards H2O2 reduction in neutral media.The fabricated sensor can be used to detect glucose level in human serum.2.An effective MOF-template strategy was employed to produce hierarchically structured leaf-like CuCo oxide 3D arrays on carbon cloth(CC/CuCo oxide).These subunits with different dimensionalities are homogeneously assembled into a unique hierarchical hollow and porous structure,resulting in an increase of the reactive specific surface area and exposure of catalytic sites.Besides,the successful integration of active nanomaterial and conductive CC substrate improves the conductivity.When evaluated as electrocatalyst for glucose detection,the CC/CuCo oxide-0.12 electrode offers an ultrahigh sensitivity of 41.02 A M-1 cm-2,a low detection limit of 26 nM.And it has been successfully applied to the determination of glucose level in spiked human serum.3.Self-supporting hierarchical Co-embedded N-doped carbon structures composed of leaf-like carbon sheets arrays and interconnected carbon nanotubes(CNTs)were synthesized on carbon cloth(CC)via dicyandiamide-assisted pyrolysis.CC/Co@C-CNTs-800-0.10 electrocatalyst possessed the hierarchical three-dimensional structure,large electroactive surface area of 4.71 cm2,fast electron transfer,abundant Co/Co-Nx active sites,and synergistic effect between Co/Co-Nx species and CNTs.Benefiting from these unique superiorities,it exhibits excellent sensing performances of H2O2 and can be used to in situ detect H2O2 released from MDA-MB-231 cells and HeLa cells.4.Co0.7Fe0.3 alloy nanoparticles(NPs)confined in N-doped carbon with yolk-shell structure in multi-beaded fibers were prepared as a bifunctional electrocatalyst.This distinctive hierarchical structure features abundant mesopores,a high BET surface area of 743.8 m2 g-1,good conductivity,and uniformly distributed Co0.7Fe0.3/Co(Fe)-Nx coupling active sites.Therefore,experimentally optimized Co0.7Fe0.3@NC2:1-800 performs excellent OER and good ORR catalytic performances.Impressively,Co0.7Fe0.3@NC2:1-800 Zn-air battery delivers a higher open circuit voltage,large power density and outstanding charge-discharge cycling stability.