Metal-decorated Nitrogen-adulterated Graphene For Water Molecule Decomposition By Theoretical Study

We learned that hydrogen production by decomposing water is currently the most efficient method for producing high-purity hydrogen.The key to the development of inexpensive,low-energy,fast-reaction catalysts has also become a research hotspot in the current academic community.We have researched thoroughly the H₂O molecule decomposition on the transition-metal?Ti?or alkali-earth?Ba and Mg?-decorated nitrogen-adulterated graphene?MN₄-graphene??M=Ti,Ba and Mg?.All the results are in view of the first-principles calculation within density functional theory.We considered three initial inequivalent configurations of H₂O-MN₄-graphene system with three different orientations of H₂O molecule on the metal atom in MN₄-graphene membranes:H₂O molecule on the top of the metal atom,with the O atom pointing away,and towards the MN₄-graphene membranes;H₂O molecule locates on top of the metal atom with H and O atoms lying in the same plane parallel to the MN₄-graphene membranes.In this paper,we have thoroughly researched the structure,electronic,magnetic and charge transfer properties of free water molecules and MN₄-graphene membranes as single-atom catalysts,described the dissociation of water molecules on MN₄-graphene membranes,and revealed the reason of the TiN₄-graphene as the best single-atom catalyst.The foremost details and completions are as follows.1.We first computed the structure of the free water molecule,and then computed the energy,density of states,three-dimensional spin-polarized charge density,and charge transfer of MN₄-graphene membranes.The metal-decorated nitrogen-adulterated graphene?MN₄-graphene??M=Ti,Ba and Mg?membranes are good candidates for single-atom catalysts?SACs?,because the single metal atom can be strongly trapped in the divacancy of the MN₄-graphene membranes and exists in the isolated form.2.The adsorption of H₂O molecules on the MN₄-graphene membranes was studied.The binding energy of the first H atom of H₂O molecule adsorbed on the MN₄-graphene?M=Ti,Ba and Mg?membranes are 2.87 eV,3.12 eV and 0.76 e V separately,which are notable smaller than that 6.01 eV for free H₂O molecule.The significant activation of the reactant H₂O molecule was observed.3.The electrons,magnetism,charge transfer of the H₂O-TiN₄-graphene system were calculated.The TiN₄-graphene membrane can remarkably decrease the potential barrier of H atom dissociated from H₂O molecule,which is a very promising SAC candidate for molecular dissociation.The composition of the paper is arranged as follows.In chapter 1,we mainly present the home and abroad study status of obtaining hydrogen energy by decomposing water molecules,the design of single-atom catalysts,and research background and the latest research progress of metal-decorated nitrogen-adulterated graphene in experiments and theories.In chapter 2,we briefly introduce the development process and basic information of the first principles based on the density functional theory.In Chapter 3,the calculation of the energy and electronic properties of MN₄-graphene is studied.In chapter 4,the adsorption and decomposition behaviors of H₂O on MN₄-graphene were studied.In Chapter 5,we summarize the entire research work.Ti atom decorated in N₄-Graphene is a promising single-atom catalyst for molecular dissociation.