| The energy conversion by the form of water electrolysis is crucial for sustainable hydrogen production.Efficient catalysts,such as platinum（Pt）-based catalysts,are needed at the cathode to promote hydrogen evolution reaction（HER）.However,due to the scarcity of Pt resources and high price,the commercial application of hydrogen production by electrolysis of water is severely restricted.Molybdenum disulfide（Mo S2）exists widely on the earth and its price is low.Under the synergistic action of Mo-S coordination,the active site of Mo S2 has HER catalytic performance similar to Pt.However,in practical application,the obstacles of poor conductivity,the blocked active sites,and the low efficiency of gas-liquid two-phase mass transfer at micro-scale seriously buried the excellent HER catalytic performance of Mo S2-based catalysts.Therefore,this paper with the account on the nanostructure design and HER performance assessment of Mo S2-based catalytic materials.A scheme to enhance the electrical conductivity was proposed,and a binder-free catalyst self-assembly method was explored.Based on this,an electrode with high micro-scale gas-liquid mass transfer efficiency was further designed,which will improve the HER performance of Mo S2-based catalytic materials.Based on the calculation of density functional theory,a competent method to improve the electron transfer efficiency of Mo S2-based catalytic materials in the HER process is proposed.The Mo S2 models of doping,defects,and spatial atomic structure changes were established,and the HER reaction processes of each model were calculated.Compared with the original untreated Mo S2 model,the effects of several typical optimization methods on improving the electron transfer efficiency of Mo S2 based catalytic materials were evaluated.It is found that on the premise of ensuring sufficient active sites,changing Mo S2 into metal has the best effect relative to promoting electron transfer in HER.On this basis,the design idea of Mo S2-based catalytic structure is proposed to enhance the proportion of metal 1T phase and introduce high conductivity nanomaterials.Based on the theoretical calculation results,three Mo S2-based catalysts were designed,including the reduced graphene oxide（r GO）loaded Mo S2,the copper（Cu）nanoparticles（NPs）compounded Mo S2,and the multi-walled carbon nanotubes（MWCNT）supported 1T-Mo S2.It is found that the conductivity of Mo S2-based catalyst can be improved by introducing r GO or MWCNT as substrate,modifying with Cu NPs,and increasing the proportion of 1T phase,to improve the catalytic performance of HER;Fuller series connection of carbon（C）substrate and Mo S2 and smaller material size can better improve HER catalytic performance;The high proportion of 1T phase in Mo S2 can further stimulate more active sites.The introduction of two-dimensional or one-dimensional C-based substrate,high conductivity,modification of resource-rich metal nanoparticles,and change of spatial atomic structure can improve the conductivity of Mo S2-based catalysts.Based on catalyst design and synthesis,the self-assembly method of Mo S2-based binder-free catalytic electrode was further explored,and 3D Mo S2/Ni3S2/Ni catalytic electrode is designed and synthesized.In practice,the catalyst needs to be supported on a conductive substrate and assembled into an electrode,so a polymer adhesive is needed in the loading process,which will block the electron transfer path and block the active site.To avoid these problems,nickel sulfide（Ni3S2）was induced to deposit Mo S2 onto the surface of Ni to form Mo S2/Ni3S2 nanoarrays.3D Mo S2/Ni3S2/Ni electrodes were prepared,and the self-adhesive assembly method of nanoparticle-guided Mo S2 based catalysts loaded into catalytic electrodes is explored.It is found that the microstructure of the 3D Mo S2/Ni3S2/Ni catalytic electrode is firm,and the starting potential is as low as13 m V in HER reaction under the electrical coupling between Ni,Ni3S2,and Mo S2,the synergistic catalytic effect produced by Mo S2/Ni3S2 nanoarray and a large number of active sites.Based on the nanostructure design idea to improve the conductivity of Mo S2 based catalytic materials and the study of binder-free self-assembly method of the catalytic electrode,1T-2H Mo S2/CFP catalytic electrode with the super hydrophilic surface was designed and synthesized,and the micro-scale gas-liquid mass transfer behavior on the electrode surface was deeply studied by combining theory and experiment.It is found that due to the super hydrophilic surface of 1T-2H Mo S2/CFP catalytic electrode,there is a rapid gas-liquid mass transfer behavior between the electrode/electrolyte/hydrogen three-phase interface in the HER process;The capillary mass transfer behavior on the electrode can increase the practical working area of the catalytic electrode;At 10 m A constant current test,1T-2H Mo S2/CFP electrode exhibits better catalytic performance and greater stability compared to Pt/C/CFP catalytic electrode due to the unique three-phase interface behavior. |
PDF Full Text Request