| The development of hydrogen energy has become a hot research in academia due to the advantages of environmental protection,renewable energy and high combustion calorific value.Electrocatalytic hydrogen production has been considered as one of the most effective methods for generating clean hydrogen energy.So far,Pt and other precious metals are the best electrocatalysts for catalyzing hydrogen production.However,limited resources and high price of precious metals limit the large-scale application of such catalysts.So there is an urgent need to find new catalysts to replace Pt catalyst.Among the multi-layer transition metal chalcogenide compounds,Mo S2 has received extensive attention due to its excellent mechanical properties,superconductivity,catalytic optical properties,and suitable energy band st ructure.Mo S2 has been an important catalyst in the field of hydrogen evolution reaction（HER）,but bulk Mo S2 showed poor catalytic activity.Therefore,a big challenge remains to modificate the Mo S2 catalyst by various improvement methods to prepare a cheap,easily available catalyst with high catalytic performance.Based on previous studies,Mo S2 nanoflowers were synthesized on the carbonized lignin（CL）substrate by hydrothermal method and annealing reduction using ammonium molybdate and thioacetamide a s raw materials,and the size range was 200～400 nm.The Mo S2 surface was doped with Ru atoms by dipping and hydrogen annealing.The morphology and structure of the synthesized Ru-Mo S2/CL nanoflower material were characterized by SEM,TEM,STEM,Raman,XRD,XPS and other characterization methods.At the same time,the electrochemical hydrogen evolution catalytic performance of the prepared Mo S2 nanomaterial was tested.In order to better study the micro-factors that affect the hydrogen evolution performance of the material and to select catalysts suitable for hydrogen evolution materials withine a short time,this article explored the establishment of a micro-area electrochemical platform and applied it to the Mo S2 hydrogen evolution test.The conclusions are listed as follows:（1）Through optimization of the conditions,Mo S2-based nanoflowers were successfully prepared on the CL substrate by using molybdate and thioacetamide as precursors.The substitution reduction method was used to replace Ru on the Mo S2surface.SEM,TEM,and STEM were characterized to analyze the morphology of the sample and the influence of different substrates on the formation of nanoflowers.Using XRD,XPS,etc.to characterize the structure of the sample,determine the uniform substitution of Ru in the sample and verify the interface effect between CL and Mo S2.（2）The hydrogen evolution performance of the Mo S2-based nanomaterials was analyzed and tested.The synthesized Ru-Mo S2/CL nanoflowers have the best hydrogen evolution activity,with the onset potential of 25 m V and the low Tafel slope of 46 m V dec-1,which is very close to the performance of Pt/C.After the cyclic test for 3000 cycles,the catalytic performance hardly changed.After the time-varying current test of 30000 s,the performance of the catalyst did not decrease significantly,and the micro-morphology structure was consistent with that before the test,and no obvious agglomeration occurred.DFT calculations prove d that when Ru atoms replace Mo atoms,the Gibbs free energy is closer to 0 than other types of defects on the basal surface or edge,and the formation energy is smaller.Therefore,after replacing Mo atoms with Ru,the hydrogen evolution reaction is promoted when the hydrogen evolution and dehydrogenation rate is better balanced.（3）Through exploring and optimizing the exposure time,development time and other conditions of SPR220 photoresist,combined with micro-nano processing technology,we successfully built a micro-area electrochemical test platform.The micro-area electrochemical device prepared under the optimized conditions has completed the hydrogen evolution test of Au and Mo S2,and the measured performance is consistent with the performance measured by th e three-electrode system in other literatures. |
