By Jun Li
Department of Chemistry, Tsinghua University, Beijing 100084, China

Nanocatalysis becomes a key frontier in heterogeneous catalysis due to rapid development of nano-sized materials. While small nanoparticles or subnanometer-sized clusters are often catalytically more active than their bulk materials, the stabilities of such particles or clusters tend to decrease.  On the other hand, with the consumption of noble metals (e.g. Ru, Rh, Pd, Ag, Os, Ir, Pt, Au, etc.) as catalysts, how to reduce the usage of expensive noble metals also becomes a key concern in controlling the cost in catalytic industries. We have recently shown that singly dispersed atoms anchored on the surface of metal oxides demonstrate robust stability and significant catalytic activities. We coined such catalyst with singly dispersed atoms as single-atom catalyst (SAC), and suggested the notation M1/EOx for SACs with single-atom M1 supported on oxides EOx [1]. Since then experimental and theoretical studies on SACs have become a hot topic in catalysis [2].

In this talk, we will provide an overview of the computational studies relevant to SACs using density functional theory (DFT) and wavefunction theory (WFT). The special stability and catalytic activity of selected SACs involving Ir1/FeOx, Pt1/FeOx, Au1/FeOx, Au1/CeO2-x, Rh1Co3/CoO1-x, Pt1@graphdiyne, and PdAu bimetallics will be explained on the basis of electronic structures and covalent chemical bonding [3-7]. Based on AIMD simulations we find that nano-catalysis can sometimes be achieved through dynamic single-atom catalysis (DSAC) [8]. The catalytic mechanisms of SACs and DSAC will be discussed based on extensive DFT modeling and simulations.

References         

1. B.-T. Qiao, A.-Q. Wang, X.-F. Yang, L. F. Allard, Z. Jiang, Y.-T. Cui, J.-Y. Liu, J. Li, T. Zhang, "Single-Atom Catalysis of CO Oxidation Using Pt1/FeOx", Nature Chem., 2011, 3(8), 634−641.
2. X.-F. Yang, A.-Q. Wang, B.-T. Qiao, J. Li, J.-Y. Liu, T. Zhang, "Single-Atom Catalysts: A New Frontier in Heterogeneous Catalysis", Acc. Chem. Res., 2013, 46(8), 1740-1748. 
3. J. Lin, A.-Q. Wang, B.-T. Qiao, X.-Y. Liu, X.-F. Yang, X.-D. Wang, J.-X. Liang, J. Li, J.-Y. Liu, T. Zhang, "Remarkable Performance of Ir1/FeOx Single-Atom Catalyst in Water Gas Shift Reaction", J. Am. Chem. Soc., 2013, 135(41), 15314-15317.
4. J.-X. Liang , J. Lin , X.-F. Yang , A.-Q. Wang , B.-T Qiao , J.-Y. Liu , T. Zhang, J. Li, ”Theoretical and Experimental Investigations on Single-Atom Catalysis: Ir1/FeOx for CO Oxidation”, J. Phys. Chem. C, 2014, 118(38), 21945-21951.
5. X. Wei, X.-F. Yang, A.-Q Wang, L. Li, X.-Y. Liu, T. Zhang, C.-Y. Mou, J. Li, "Bimetallic Au−Pd Alloy Catalysts for N2O Decomposition: Effects of Surface Structures on Catalytic Activity", J. Phys. Chem. C, 2012, 116(10), 6222−6232.
6. B.-T. Qiao, J.-X. Liang, A.-Q. Wang, C.-Q. Xu, J. Li, T. Zhang, J.-Y. Liu, "Ultrastable Single-Atom Gold Catalysts with Strong Covalent Metal-Support Interaction (CMSI)", Nano Res., 2015, doi: 10.1007/s12274-015-0796-9
7. S.-R. Zhang, L. Nguyen, J.-X. Liang, J.-J. Shan , J.-Y. Liu, A. I. Frenkel, A. Patlolla, W.-X. Huang, J. Li, F. Tao, "Catalysis on Singly Dispersed Bimetallic Sites", Nature Commun., 2015, 6, 7938.
8. Y.-G. Wang, D.-H. Mei, V.-A. Glezakon, J. Li, R. Rousseau, "Dynamic Formation of Single-Atom Catalytic Active Sites on Ceria-Supported Gold Nanoparticles", Nature Commun., 2015, 6, 6511.