In recent years,based on the success in nanoelectronic semiconductor devices,the emerging field of on-chip electrocatalytic microdevices,focusing on the special structure of electrocatlysis,electrochemical interface,has emerged as a powerful platform to analysize explore the electrocatlysis.The individual catalysis on the on-chip microdevice could be precisely designed and in situ controlled,which are essential for eliminating distractions from multiple factors and allow(semi-)quanti-tative electrochemical studies.This unique device configuration enables several advantages,such as adjustable morphology and microstructure of individual catalysts,directly probe electrochemical processes to obtain deteriming factor for catalysis performance,which can effectively exclude orher factors.Furthermore,on-chip microdevice can be used to identify the catalytically active sites by selectively exposing the area of interest on a microscopic catalyst nanosheet using e-beam lithography,which provides a direct and precise strategy to probe the spatially resolved electrocatalytic activities.The micro-device can provide a new direction and opportunities for performance optimization of catalysis.In this paper,by establishing a micro-electrochemical system and conducting micro-electrochemical tests on specific structures,positions,interfaces,etc.,the relevant mechanisms are accurately and deeply studied,and the catalytic performance is improved.The specific research contents are as follows:(1)Construction of micro-electrochemical system.First of all,for the lithography machine equipment,four kinds of photoresists were used to explore,and the research found that the photoresist SPR220-3A,after the micro-electrode was fabricated,the entire device structure and performance were as expected,the electrode channel was clean and the substrate had no residue.photoresist,and exhibits good electrical properties,so this photoresist is selected for our micro device fabrication.On the basis of the photoresist screening research,the probe station(MPS150)was used as the test platform,the metal electrode connected to the exposed area on the nanodevice was used as the working electrode,and the Pt wire with a diameter of 0.6 mm was used as the counter electrode.The Ag/Ag Cl electrode was used as a reference electrode,and the electrochemical performance of the system was tested by an electrochemical workstation(CHI 660E)to ensure the construction of a reliable micro-electrochemical system.(2)Design and regulation of PtNPs@MoS2 and microelectrochemical studies.By developing a CVD co-growth method,mixing H2Pt Cl6 and Na2Mo O4 precursor solutions for the synthesis of PtNPs@MoS2 structures different from conventional triangular and hexagonal structures.Afterwards,the electrochemical research was carried out through the self-built micro-electrochemical platform,and the PtNPs@MoS2 had better electrocatalytic performance than MoS2,and the reasons for the better catalytic performance of PtNPs@MoS2 were further studied.Through electrical tests PtNPs@MoS2 was found to have higher carrier mobility relative to MoS2.In addition,the carrier mobility under simila r conditions of(35)GH*was investigated by adjusting the concentration of the precursor liquid,and the self-gating enhanced carrier effect of the PtNPs@MoS2 semiconductor electrocatalyst was demonstrated based on microdevices.Catalytic tests,which analyz e the strong correlation between carrier mobility and hydrogen evolution performance,illustrate the effect of self-gating generated during electrocatalysis on the hydrogen evolution performance of semiconductors.This work provides a rational approach to enhance the activity of inert MoS2 basal planes,and demonstrates the importance of carrier mobility in the catalytic process through experiments and theoretical calculations.(3)The construction of WSe2/MoS2 heterojunction and the study of micro-electrochemical properties.Type II heterojunctions were constructed based on P-type semiconductor tungsten selenide(WSe2)and N-type semiconductor molybdenum sulfide(MoS2),and their interface physical properties were investigated by micro-electrochemical tests.Raman spectroscopy(Raman),photoluminescence spectroscopy(PL)and Kelvin probe force microscopy(KPFM)were carried out on the WSe2/MoS2 heterojunction region,combined with micro-nano fabrication and assembly to construct a micro-area electrochemical reactor for accurate testing Electrochemical activity in the heterojunction region.The effect of WSe 2/MoS2interfacial electric field on the hydrogen evolution performance was studied by micro-electrochemical tests on different electrode ends in contact w ith WSe2 and MoS2.With the help of the precise and efficient characteristics of micro-electrochemistry,more information can be obtained by changing the relevant conditions,so that we can better analyze the information of the interfacial charge transfer of the heterojunction and thus better understand the structure of the heterojunction.(4)Stress-regulated electrochemical performance of MoS 2 microdomains.The Si O2 was etched to different degrees by BOE(etching solution),the stress of MoS 2 on the substrate was controlled,and the influence on the electrochemical performance of the micro-domain was studied.First,the etched substrate was placed in a vacuum tube furnace to grow MoS2 by CVD,and then optical testing and microstructure characterization were performed.The results show that MoS2 grown directly on the etched substrate,PL exhibits a unique luminescence intensity distribution,and the disordered lattice structure and irregular lattice growth of MoS 2 are verified by scanning transmission electron microscopy(STEM).In the micro-area electrochemical test,its hydrogen evolution performance will not improve with the introduction of light,showing weak sensitivity to light.In order to accurately analyze the effect of stress on MoS2,the regularly arranged MoS2 crystals were transferred to different degrees of etching substrates by wet transfer of PMMA,which showed good catalytic performance in the hydrogen evolution test,and had different sensitivity to light.sex.When the material is subjected to large deformation,its photo-excited carriers will be limited to a certain extent.Therefore,this method of substrate controllable etching will help us to study the influence of stress on the hydrogen evolution performance of two-dimensional materials,and to analyze the physical properties of two-dimensional materials from a multi-angle and more microscopic perspective.And the influence of chemical properties,deepen our understanding of two-dimensional materials. |