Electrochemical Preparation And Application Of Several Micro/nano-structured Metal Electrodes

Compared with macro-materials,micro/nanomaterials of various metals with unique structure possess a series of special effects such as surface effect,small size effect,quantum tunneling effect,quantum size effect,and so on,leading to the specific properties and wide usage in electrocatalysis,sensor,information storage,electronics,surface-enhanced spectroscopies,etc.Thus,the exploration of simple,mild,green,cheap and controllable methods for preparing micro/nano-structured metal materials is a hot topic and of great significance in application fields.Electrochemical methods can be used to synthesize various micro/nano-structured metal materials,such as nanowires,nanotubes,nanodendrites.Compared with physical routes and chemical methods,electrochemical methods have the advantages of low cost,high efficiency,wide application range,good controllability,simple equipment and short time.In this paper,several rapid and simple electrochemical methods for the synthesis of micro/nano-structured metal materials have been developed,and their applications in electrocatalytic reduction of 4-NP and oxalic acid,nonenzymatic glucose detection,and SERE were also studied.The main contents are as follows:1.We have prepared the micro/nano-dendritic bismuth film electrode for the electrocatalytic reduction of 4-NP by one-step electrochemical method.The smooth bismuth electrode was treated in H2SO4 solution using the electrochemical method of double potential steps,in the process of which micro/nano-dendritic bismuth film was fabricated within 10 minutes.During anode potential step,the bismuth electrode was oxidized to form oxides and soluble salt;during cathode potential step,the oxide species of bismuth were reduced to bismuth atoms which gathered on the surface of the bismuth electrode forming micro/nano-structured metal bismuth.The preparation was carried out in the room temperature without adding any reaction precursors and protectors.The roughened bismuth film electrode was characterized by scanning electron microscope,Raman and X-ray diffraction.And the catalytic effect of micro/nano-structured bismuth electrode toward 4-NP was studied.2.We have prepared the micro/nano-dendritic tin film electrode for the electrocatalytic reduction of oxalic acid by one-step electrochemical method.The smooth tin electrode was treated in NaOH solution by the electrochemical method of double potential steps,in the process of which micro/nano-dendritic tin film was synthesized in several minutes.During anode potential step,the tin electrode was oxidized to form oxides and soluble salt;during cathode potential step,the oxide species of tin were reduced to tin atoms which gathered on the surface of the tin electrode forming micro/nano-structured metal tin.The electrochemical method is simple,mild,fast and green.And the roughened tin film electrode was characterized by scanning electron microscope,Raman and X-ray diffraction.The catalytic effect of micro/nano-structured tin electrode toward oxalic acid was also studied.3.We have prepared the urchin-like Cu nanowire arrays for non-enzymatic glucose sensor by a two-step electrochemical method.First of all,a novel surface conversion of smooth copper electrodes into flower-like Cu2Se nanosheets was realized in a solution of Na2SO4 containing Na2SeSO3 by a cathodic polarization.Then the flower-like Cu2Se nanosheets was further transformed into urchin-like Cu nanowire arrays by cyclic voltammetry in a solution of NaOH.The mechanisms for these fast anomalous conversions have been elucidated in detail.The in situ formed urchin-like Cu nanowire arrays from the flower-like Cu2Se can serve as an advanced glucose sensor which possessed these merits of high sensitivity(3745 ?A(mmol dm-3)-1 cm-2),wide linear range(up to 6.11 mmol dm-3),low detection limit(0.51 ?mol dm-3),good anti-interference and long-term stability(12 weeks)and reliable accuracy in the detection of glucose in human blood.4.We reconstructed the smooth copper surface into copper nanoneedle arrays as a highly sensitive SERS substrate by a two-step electrochemical method.The Cu nanoneedle arrays were rapidly fabricated by surface reshape of the smooth copper surface by two steps that first in the solution of Na2SO4 containing Na2SeSO3 by cathodic polarization then in NaOH solution by cyclic voltammetry.The surface enhanced Raman scattering effect of copper nanoneedle arrays was studied.The influence of cathodic polarization time and cyclic voltammetric cycles was investigated in detail,and the Raman enhancement factor was calculated.