中国科学院大学学报2022，Vol.39Issue(2)：193-200,8.DOI:10.7523/j.ucas.2020.0041
NO在赤铁矿(0001)表面吸附的第一性原理计算
Ab initio simulations of NO adsorption on hematite(0001)surface:PBE versus PBE+U
摘要
Abstract
NOx(x=1,2)are major air-pollutants detrimental to human health and much effort has been devoted to find efficient photocatalysts capable of removing NOx from air(de-NOx).Recent experiments indicate that hematite(α-Fe2O3)is a promising de-NOx photocatalyst.However some key features of the NO adsorption on the hematite surface remain unclear,hindering further comprehension of the photocatalytic process.Here we study the adsorption of NO on the hematite(0001)surface using the PBE+U method with a dispersion correction(vdw)in the framework of density functional theory(DFT).We find the addition of a Hubbard U term in the DFT Hamiltonian strongly affects the adsorption properties,with the adsorption energy(-0.64 eV)decreased by 50％with respect to those of PBE(-1.31 eV).This decrease is attributed to two factors;(i)the U term shifts the energy of Fe 3d orbitals away from the valence band maximum,making them chemically less active;(ii)the NO molecule has an unpaired π* electron and is more sensitive to the electronic structure of the substrate.In contrast to the inclusion of U,the dispersion correction causes little change to the adsorption properties except increases the adsorption energy by about-0.18 eV.We use the Langmuir formula to calculate the thermal equilibrium coverage of NO on the hematite(0001)surface and find predictions made with the PBE+U vdw are more consistent with experiments.These results highlight the importance of strong electronic correlations in describing the hematite surface reactions,and may serve as a starting point to unravel the complete photocatalytic mechanism.关键词
三氧化二铁/一氧化氮/光催化/Langmuir/大气污染Key words
hematite/NO/photocatalysis/Langmuir/air pollution分类
天文与地球科学引用本文复制引用
吴翠霞,孙涛,FABRIS Stefano,杜林..NO在赤铁矿(0001)表面吸附的第一性原理计算[J].中国科学院大学学报,2022,39(2):193-200,8.基金项目
Supported by National Natural Science Foundation of China(41972044,91644214)and Strategic Priority Research Program(B)of Chinese Academy of Sciences(XDB18000000) （41972044,91644214）
