The Synthesis Of Layered Transition Metal Seleniums And Their Hybrids&Performance In Electrochemical Hydrogen Evolution

Hydrogen is considered as a promising renewable clean energy to meet the growing demand for energy and environmental concerns caused by the severe consumption of traditional fossil fuels.As one of the most efficient and sustainable productions of hydrogen,water electrolysis is central to several clean-energy technologies,including fuel cells and solar water electrolyzers.The key aspect of water electrolysis is high effective electrode catalysts for hydrogen evolution reaction?HER?.Recently,materials in nanoscale are considered as good electrocatalysts for HER,especially nanostructured transition metal phosphides and layerd transition metal dichalcogenides.Herein,we report new high effective non-noble catalysts synthesized by combining the CoP NPs with WSe₂ nanosheets or MoSe₂ nanosheets.The enhanced electrocatalytic HER performance of the hybrids is revealed by systematically electrochemistry test,suggesting a promising way to design advanced HER catalysts.Our main results of this thesis are shown below:?1?In our first part,the CoP/WSe₂ nanosheets hybrids were successfully prepared.The morphology and valence state of the as-prepared samples were characterized by SEM,TEM and XPS test.The electrocatalytic activities of the samples were evaluated by electrochemical test.We found that all the hybrids showed higher catalystic activity than pure CoP and WSe₂ nanosheets,suggesting their synergistic catalytic effect in HER.Particularly,in 0.5 M H₂SO₄,the hybrid with an optimized CoP to WSe₂ mass ratio of 1:1 has the highest current density of 102.9mA/cm² at 300 mV vs RHE and excellent long-term stability.?2?In the second part,we synthesized new high effective non-noble catalysts by simply combining the CoP NPs and MoSe₂ nanosheets in different mass ratios.The XRD,SEM,TEM,XPS test were performed to investigate the morphology and valence state of the as-prepared samples.By electrochemistry test,we finally found that the hybrid named as CoP/MoSe₂–3 under the set mass ratio of 3:1?CoP NPs to MoSe₂ nanosheets?shows the optimal electrocatalytic performance in HER with the current density of 155.14 mA/cm²at 300 mV vs RHE,much higher than that of bare CoP NPs,blank MoSe₂ nanosheets and all the hybrids under other mass ratios.