| The two-dimensional layered structure transition metal dichalcogenides?TMDs?are a kind of high-efficiency and low-cost electrocatalysts for hydrogen evolution in electrolyzed water with good development prospects.Previous studies on the performance of electrocatalytic hydrogen evolution of TMDs have focused on two-dimensional layered materials of group VIB,such as Mo S2 and WS2.Compared with VIB-TMDs,VS2 as a typical VB-TMD has better hydrogen adsorption Gibbs free energy,higher conductivity and excellent thermal stability.VS2 is considered as an electrocatalyst with more development potential.It is worth mentioning that the catalytic activity of some 2H phase electrocatalysts mainly comes from the edge active sites,and there are basically no active sites on the basal plane.The catalytic activity of1T phase VS2 is not only derived from the edge,but also derived from the basal plane which makes VS2 stand out among many electrolyzed hydrogen evolution catalysts.In this thesis,V2+doped 1T-VS2mesoporous nanosheets are synthesized for the first time as an excellent electrocatalyst for hydrogen evolution reaction?HER?.VS2·NH3precursor that is obtained by a one-step hydrothermal method,is soaked in an acidic solution to remove NH3 molecules intercalated in the nanosheets,consequently resultingincrease the vacancies and disorders of the VS2 basal plane as new active sites.Furthermore,the existence of mesopores can provide a large number of additional edge sites.Thus,a large number of defects are generated as electrocatalytic active sites,which greatly improved the catalytic activity of the nanosheets.Due to the synergisticdoped 1T-VS2 mesoporous nanosheet sample become a highly active catalyst for HER.It exhibits excellent electrocatalytic kinetics with a very low onset potential?19 m V?excellent electrochemical stability in the long-term stability test,the generation of H2can be carried out at a stable current density of about 21.4 m A cm-2 for 70 h. |
PDF Full Text Request