A Density Functional Theory Study On The Nature Of Band-Gap Engineering Adsorption Properties Of Molecules On Oxides And Oxide-Supported Catalysts

As the inherent electronic properties of semiconductor oxides,band gaps are universally regarded as pivotal determinants of photocatalytic.According to previous investigations and our recent endeavors,there is a tangible correlation between the band gap values of semiconductor oxides and their thermal catalytic performance:the oxide possessing a narrower band gap typically exhibits enhanced catalytic reactivity.It is of great significance to systematically investigate the band gap engineering thermal catalytic performance of oxides and their supported catalysts.In this research,the Density Functional Theory（DFT）calculations were employed in revealing the band gap regulation phenomena in Ti O₂-based systems.By manipulating the Ti O₂ band gap via means such as layer control and ion doping,we demonstrate the nature of band gap engineering surface adsorption properties.Concurrently,we also report the phenomenon that the band gap of carrier affects the interactions between the loaded active components and their supports,and ultimately influences the catalytic performance.The specific research contents are as follows:Part I:To elucidate the physical and chemical essence of band gap regulation on surface adsorption,we constructed two-dimensional（2D）layered（n L）Ti O₂（110）models in which the band gap values exhibited odd-even oscillations with increasing layers.Employing DFT calculations,we investigated the adsorption of H atoms and CO molecules and discovered a linear correlation between material band gap values and surface adsorption energies.Subsequently,by combining the electronic analysis of2L and 3L Ti O₂（110）before and after adsorption with molecular orbital theory,we established a novel H/CO-O bonding mechanism,unveiling the essence of the band gap regulation phenomenon on surface adsorption energies for semiconductor oxides.Part II:To unveil the influence of semiconductor oxide band gaps on the surface-loaded active components,we established metal-loaded Ru₁/n L Ti O₂ and metal oxide-loaded Ru O₂/n L Ti O₂ models,and through DFT calculations,probed the impact of carrier band gap variations on the interaction between active components and supports.The results reveal that the decrease in carrier band gaps enhance the interaction between carriers and active components（Ru₁ and Ru O₂）,which furtherly alters the electronic property of the active components and restrains their activation capability for small molecules,CO and O₂,respectively.Part three:To investigate the influence of carrier band gap affected by transition metal ions doping on metal-support interaction and molecular adsorption properties for supported Ru₁ single atom catalyst,the tetragonal rutile Ti O₂（110）model doped with3d transition metals was established.As modulating the material’s bandgap by substituting Ti ion in the sub-layer with Cr,Mn,Fe,Co,and Zn ions,we employed DFT calculations to thoroughly investigate the impact of bandgap alterations on the surface properties of Ti O₂.The results reveal that doping with Cr,Mn,Fe,Co,and Zn introduces vacant bands in the forbidden gap of Ti O₂ in various forms,resulting in a reduced band gap.This enhancement in surface adsorption capabilities strengthens the interaction between the supported Ru₁ and Ti O₂,ultimately diminishing the capacity to activate CO of the Ru₁ atom.