Synthesis Of Hierarchically Hollow Structured Transition Metal Materials And Electrochemical Performance Research

In the field of analytical detection,electrochemical sensors are widely used due to their advantages of high reproducibility,high response and excellent selectivity.The sensitive material of electrode is the key point for the performance of electrochemical sensors.Transition metals are often used as electrochemically sensitive materials due to their low cost and large reserves,however,their own conductivity limits further improvement of electrochemical response.It has been shown that using electrochemical kinetic principles to accelerate the electron transfer process can significantly improve electrochemical performance,and electrochemical kinetic principles are inextricably linked to the design of sensitive materials,so efforts have been devoted to the development of structurally excellent electrochemically sensitive materials.Among them,three-dimensional hollow materials have a unique structure with a large specific surface area that can provide sufficient catalytic active sites,and their porosity not only provides a large number of diffusion channels for the materials to be measured,but also alleviates the stress release during use.Again,by modifying the three-dimensional materials with low-dimensional materials,the low-dimensional materials provide more active sites and electron transfer channels,further increasing the specific surface area and volume occupancy of the structures,and bringing into play the synergistic effects of the structures to build electrochemical sensors with excellent performance.Based on this,this paper designs graded hollow structured transition metal materials as electrochemically sensitive materials,and improves the specific surface area and volume occupancy of the materials by constructing three-dimensional hollow structures,which are used as carriers of transition metals to improve the electrochemical performance of the materials,as follows:1.The Cu S nanocages were decorated internally and externally with Co（OH）₂nanosheets（IE Co（OH）₂ NSs/Cu S NCs）using a S₂O₃^2-involved coordinated etching and precipitation（CEP）method.Interestingly,the external Co（OH）₂ NSs grew vertically on the outer surface of the Cu S NCs,while the internal Co（OH）₂NSsinteracted with each other,forming a cage-like structure.The external Co（OH）₂NSs provided sufficient active sites and diffusion channels for glucose,and the inner Co（OH）₂ nanocages（Co（OH）₂ NCs）improved the volume occupying rate of the hollow materials,leading to enhanced electrocatalytic activity.As a detection electrode for glucose,IE Co（OH）₂ NSs/Cu S NCs modified glassy carbon electrode（IE Co（OH）₂NSs/Cu S NCs/GCE）exhibited two satisfying sensitivities of 2984.2 and 1858.4μA m M^-1 cm-² within the two linear ranges of 0.223μM-0.75 m M and 0.95 m M–3.35m M,respectively.Furthermore,IE Co（OH）₂ NSs/Cu S NCs/GCE had a low limit of detection of 0.223μM.These results showed that IE Co（OH）₂ NSs/Cu S NCs/GCE looked promising for electrochemical sensing of glucose due to the synergy between the Co（OH）₂ NSs and the Cu S NCs,and high volume occupying rate provided by the internal Co（OH）2 NSs.2.Co₃S₄@Cu S@Co₃S₄ HNBs were successfully prepared using a multi-step precise CEP modulation method with Cu₂O as the template,and the specific surface area was increased by 31.1%compared to the structure without internal Co₃S₄ NBs.As a multi-nonenzymatic dopamine（DA）electrochemical sensor,Co₃S₄@Cu S@Co₃S₄HNBs exhibited a high sensitivity of 1073.2μA m M^-1 cm^-2 in the range of 5-1150μM.The current response obtained in the presence of different interfering substances did not exceed 7.23%±0.6.The measured recoveries were between 90.37%and 102.41%.Moreover,the RSD values were less than 3.1%,indicating the promising potential of Co₃S₄@Cu S@Co₃S₄ HNBs/GCE in non-enzymatic DA electrochemical sensors3.TA-Co NBs with hollow structures were prepared by a simple etching method involving metal organic framework materials（MOF）,and further structures（C HNCs@Co₃O₄ NPs@Mn O₂ NSs）with Mn O₂ nanosheets and Co₃O₄ nanoparticles simultaneously mosaicked on the surface of 3D hollow carbon nanocages were prepared.The materials were modified on GCE for glucose detection,and HC HNCs@Co₃O₄ NPs@Mn O₂ NSs/GCE exhibited excellent sensitivity(792.21μA m M^-1cm^-2)and low detection limits（1.147μM）.In addition,C HNCs@Co₃O₄NPs@Mn O₂ NSs/GCE has good reproducibility and repeatability.Finally,the glucose recoveries measured by C HNCs@Co₃O₄ NPs@Mn O₂ NSs/GCE in real human serum samples ranged from 91.2%to 98.8% with standard deviation values（RSD）less than 5.3%.