The Construction Of Nano-catalyst Based On Molybdenum Dioxide For Electric Hydrogen Evolution Reaction

Water electrolysis technology for hydrogen has been an ideal solution to solve the energy crisis and the environmental pollution due to its cleanliness and high efficiency.However,the application of electrolytic water to hydrogen is still limited by the high cost of this process.Base on above problem,developing the stable,inexpensive and efficient alternative to platinum catalyst is quite appealing with the aim of providing cost competitive hydrogen.MoO₂ exhibits noticeable metallic nature,strong acid-resistance and as-exhibited high chemical stability.These interesting properties grant it highly desirable in hydrogen evolution reaction?HER?as cathode material.The serious issue is that the bulk MoO₂ offer relative fewer active sites,which impede the further widely application for HER.In this thesis,we are mainly committed to prepare high active and stable MoO₂ materials and study their performance for HER,which include the following two parts:1.The MoO₂ supported on the P-CNTs?MoO₂/P-CNTs?was calcined at high temperature by a simple and easy-to-operate process.And the HER activity was studied by various electrochemical assessments.2.Starting from the preparation of ultra-small nanoparticles,we first proposed a nano-Cu-mediated method to adjust the size of nanoparticles.The controllable synthesis of ultra-small MoO₂ was synthesized on PDDA/rGO?MoO₂/PDDA-rGO?using mild hydrothermal method.We put forward the mechanism of the formation of ultra-small MoO₂ nanoparticles and in depth studied the HER performance of MoO₂/PDDA-rGO.The initial hydrogen evolution potential of MoO₂/P-CNTs was-78 mV,the Tafel slope was 45 mV dec-1,the exchange current density was 0.27 mA cm-2,and the current density at constant voltage can be maintained for 50 hours without attenuation.MoO₂/PDDA-rGO possessed an onset potential as low to-42 mV vs.reversible hydrogen electrode?RHE?,a calculated Tafel slope only 42 mV dec-1,and the exchange current density was 0.52 mA cm-2,a large surface area was up to 1076 cm2 and good cycling stability was more than 40 h.This original shape,structural characteristics were remained after the stability test.