| Facing the challenges of energy crisis and the interrelated environmental issues,renewable and clean energy have attracted widespread attentions.Hydrogen has been considered as a promising alternative to overcome our reliance on fossil fuels because of its cleanliness,high-energy density,and renewability.Electrochemical water splitting(2H2O ? 2H2 + O2)provides an effective way to convert electrical energy into chemical energy,which is an environmentally friendly method to meet the global energy demands.In this dissertation,Co-based bimetallic oxides and selenides showed high performance and high stability catalysts through different modification treatments.Through a series of electrochemical characterization,the catalytic reaction mechanism was fully discussed.We obtained NiCo2O4 nanorods by annealed in different atmospheres.XPS and EPR showed that there were some oxygen vacancies in the samples.Demonstrating that by modifying the internal structure of the material,the catalytic HER performance is significantly improved.Attributed to the increased conductivity caused by oxygen vacancies in NiCo2O4 and the full exposure of electrochemically active sites,which improved the charge transfer efficiency and thus promoted the catalytic reaction.We systematically investigated and compared the activity of MnCo-based electrocatalysts(i.e.selenide,oxide,and hydroxide)for the oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)in alkaline solutions.The superior activity of MnCo selenides could be attributed to the high intrinsic conductivity and the high surface active area.Further,the synergy between Mn and Co lowers the energy barrier for catalysis and help to stabilize the material.The bimetallic MnCo selenides with yolk shell structures possess the optimal electrochemical performance with a low cell voltage of 1.66 V at the current density of 50 mA cm-2,outperforming most of the earth-abundant electrocatalysts. |
PDF Full Text Request