Surface Adsorption and Catalysis Aug 28, 2019 Surface Adsorption Catalysis 595 Catalysts play a vital role in human activities, chemical industries and may be the unique way to deal with current energy and environmental crisis. Scientists have been working on the design of novel catalysts with high efficiency at low cost, high selectivity and high stability. However, the process is always hampered by the inherent complexity of the structures on catalysts and the reaction mechanism . Sulfur Poisoning Issue: The extraordinary sulfur enhanced CO adsorption on Au surface is extremely curious to many scientists. The Sinduced charge can introduce a significant d band shift on Au/Ag with respect to EF due to their narrow density of states at EF and thus strengthens CO adsorption subsequently. With the charge effect model, we successfully uncovered the phenomenon, and predict S can also stabilize NO adsorption on Au. Water-gas-shift: Ni additives in the Cu catalysts could enhance the activity to water-gas-shift(WGS) reaction, but the undesirable methanation would arise synchronously, degrading its selectivity to WGS. Through the comparison of H2O and CO dissociation, we suggest CuNi catalysts with highly dispersed Ni sites should exhibit high performance to WGS. Further, we propose a developed Cu-Ni system, NiO1-x/Cu, which may show both excellent activity and selectivity to WGS. H-Bond enhanced dissociation: The experimental observation that H2O could be dissociated easily on Si(100) surface in low temperatures was not well understood. Herein, we find that the additional H2O molecule tends to cluster with the preadsorbed one with a large adsorption energ, and lowers the dissociation barrier dramatically. Moreover, its competition with Pauli exclusion explains that isolated H2O is inert on silicene while isolated NH3 not. #### References  Meunier, F.C., Acs Nano, 2, 2441, (2008).  Christensen, C.H. and Nøskov, J.K., Science, 327, 278, (2010).  Li-Yong Gan, et al, J. Chem. Phys., 136, 044510, (2012).  Li-Yong Gan, et al, J. Chem. Phys., 133, 094703, (2010).  Li-Yong Gan, et al, J. Phys. Chem. C, 116, 745, (2012).  Xiang Huang, et al, J. Phys. Chem. C, 118, 24603, (2014).  Xiang Huang, et al, J. Phys. Chem. C, 120, 19151, (2016).