The First Principle Study On The Oxide Of CaTi₅O₁₁ And Phosphide Of CoP With Catalytic Hydrolysis

Hydrogen production has become an important means to solve the current energy crisis because of its high combustion value and no pollution,making it possible to act as a new energy for fossil fuel.So it is critical to develop new catalysts to produce hydrogen.And the development of photocatalyst and electricity catalyst have become one of the most promising areas.According to the research progress of calcium titantie and transition metal compound.We have studied the catalytic performance of CaTi₅O₁₁1 and CoP with doping different elements by the DFT.CaTi₅O₁₁1 as a new type oflayered perovskite,which its structure is very similar to titanium dioxide,can be used as a photocatalyst to decompose water.But its bandgap of3.58eV is still very large for photocatalytic water,thus we have considered to doped different elements to modify the band edge of CaTi₅O₁₁.Since doping N,C,S,V,Cr and N-V can effectively adjust the geometry and the structure of CaTi₅O₁₁,reducing its bandgap to improve the photocatalytic efficiency.Although the single dopant will reduce its bandgap,the impurity state in the middle of the bandgap will accelerate the recombination of electron-hole,which will inhibit photocatalytic efficiency.The calculated binding energy indicates that the codoping has a better stability with respect to single doping.N-V not only reduces the bandgap of CaTi₅O₁₁,but also eliminates the possible intermediate impurity state.What's more importantly,N-V?ii,iv?has appropriate band positions for the hydrogen evolution potential and oxygen evolution potential,making it a potential photocatalytic material.The transition metal compound is a novel non-noble metal compounds which have excellent hydrogen evolution reaction properties and thermal stability,making it possible as a electrode material to replace the Pt.Among them,Cobalt phosphate as a rich reserves of phosphide,has a very good hydrogen evolution reaction performance,but still far from the requirement of people.Doing with different elements can modify the electronic structure of cobalt phosphate,thus effective its performance of hydrogen evolution reaction.Doping Ni,Cu,Zn,Ga,Sn will improve the electrocatalytic performance of CoP.We have also carried out theoretical calculation of charge and density of states.Those calculations provide a theoretical basis for analysis of other transition metal compounds.