摘要
We report herein a new sulfur-functionalized MXene Ti_(2)C(Ti_(2)CS_(2))-supported osmium-metal single-atom catalyst(SAC) Os_(1)/Ti_(2)CS_(2)with high low-temperature catalytic activity for CO oxidation. Using periodic density functional theory calculations, the most stable SAC, Os_(1)/Ti_(2)CS_(2), has been screened from a series of group 8–11 transition metal SACs M_(1)/Ti_(2)CS_(2)(M = Fe, Co, Ni, Cu;Ru, Rh, Pd, Ag;Os, Ir,Pt, Au). The calculations show that it is favorable for O;and CO to be coadsorbed on the Os;single atom(SA) of Os_(1)/Ti_(2)CS_(2)and the adsorption energy of the first O_(2) molecule is slightly higher than that of CO. Moreover, the termolecular co-adsorption of O_(2)+ 2CO on Os_(1) SA is also possible, which is favorable for CO oxidation on Os_(1) SA through a novel threemolecule reaction mechanism. Accordingly, four different catalytic mechanisms, the Langmuir–Hinshelwood(L–H),Eley–Rideal(E–R), termolecular Langmuir–Hinshelwood-A(TLH-A) and termolecular Langmuir–Hinshelwood-B(TLHB), are systematically studied for CO oxidation by O_(2) on Os_(1)/Ti_(2)CS_(2). The theoretical studies indicate that the TLH-B mechanism is the most feasible for CO oxidation with the reaction barrier energy of only 0.74 e V, which is far lower than for L–H, E–R and TLH-A with barrier energies of 1.06, 1.09 and1.47 e V, respectively. The results provide fundamental understanding to the surface chemistry of MXene and designing new sulfur-functionalized two-dimensional MXene catalytic nanomaterials.
本文报道了一种对CO氧化反应具有低温催化活性的新型硫功能化MXene-Ti_(2)C(Ti_(2)CS_(2))负载的锇金属单原子催化剂Os_(1)/Ti_(2)CS_(2).通过密度泛函理论计算,从一系列过渡金属(M=Fe,Co,Ni,Cu;Ru,Rh,Pd,Ag;Os,Ir,Pt,Au)中筛选出最稳定的锇金属单原子催化剂.计算结果表明,Os_(1)/Ti_(2)CS_(2)有利于O_(2)和CO的共吸附,且O_(2)分子的吸附能略高于CO分子.此外,由于O_(2)+2CO能稳定地共吸附在Os;单原子上,CO氧化反应可能通过三分子反应机理进行.因此,我们研究了CO在Os_(1)/Ti_(2)CS_(2)单原子催化剂上发生氧化反应的四种不同的催化机理:Langmuir-Hinshelwood(L–H)、Eley Rideal(E–R)、termolecular Langmuir-Hinshelwood-A(TLH-A)和termolecular Langmuir-Hinshelwood-B(TLH-B)机理.结果表明TLH-B机理最可能发生,其反应势垒仅为0.74 e V,远低于L–H、E–R和TLH-A的反应势垒(分别为1.06,1.09和1.47 e V).上述研究结果有助于理解MXene的表面化学并设计稳定的新型二维硫端基MXene催化材料.
作者
Yang Meng
Jin-Xia Liang
Chun Zhu
Cong-Qiao Xu
Jun Li
孟洋;梁锦霞;朱纯;许聪俏;李隽(School of Chemistry and Chemical Engineering,Guizhou University,Guiyang 550025,China;Department of Chemistry,Southern University of Science and Technology,Shenzhen 518055,China;Department of Chemistry and Key Laboratory of Organic Optoelectronics&Molecular Engineering of Ministry of Education,Tsinghua University,Beijing 100084,China)
基金
supported by the National Natural Science Foundation of China (21963005, 21763006, 22033005 and 22038002)
the Natural Science Foundation of Guizhou University ([2021]40 and [2020] 32)
Guangdong Provincial Key Laboratory of Catalysis (2020B121201002)。
