In this works, co-adsorption of CO, H2O and mechanism calculations of water gas shift reaction (WGSR) on ZnO 1010 catalyst surface using the density functional theory (DFT) was investigated. Performing the most stable site of co-adsorbed CO and H2O with configuration and adsorption energy on the catalyst surface were indentified. | Vietnam Journal of Science and Technology 55 (6A) (2017) 95-104 CO-ADSORPTION OF CO, H2O AND MECHANISM OF WATER GAS SHIFT REACTION ON ZnO 10 1 0 CATALYST SURFACE: A DENSITY FUNCTIONAL THEORY STUDY Vo Thanh Cong1, *, Do Quy Diem1, Nguyen Minh Quang1, Pham Thanh Tam1, Pham Van Tat2 1 Faculty of Chemical Engineering, Industrial University of Ho Chi Minh City, 12 Nguyen Van Bao Street, Go Vap District, Ho Chi Minh City,Viet Nam 2 Faculty of Science and Technology, Hoa Sen University, Lot 10. Quang Trung Software Park, Tan Chanh Hiep Ward, 12th District, Ho Chi Minh City, Viet Nam * Email: vothanhcong@ Received: 15 June 2017; Accepted for publication: 21 December 2017 ABSTRACT In this works, co-adsorption of CO, H2O and mechanism calculations of water gas shift reaction (WGSR) on ZnO 10 1 0 catalyst surface using the density functional theory (DFT) was investigated. Performing the most stable site of co-adsorbed CO and H2O with configuration and adsorption energy on the catalyst surface were indentified. The carboxyl mechanism of WGSR was proposed and examined then. Based on carboxyl mechanism, the beginning of reaction pathway with the most stable co-adsorbed CO and H2O configuration as initial state on ZnO 10 1 0 catalyst surface was considered. The resulted calculations pointed out that the pathway of WGSR mechanisms on the surface was favorable kinetically with rate-determining steps of eV. Keywords: ZnO 10 1 0 catalyst surface, WGSR, co-adsorption, DFT. 1. INTRODUCTION Currently, the 80 % approximation of energy resource from fossil fuels was demanded to use in the present world [1]. However, the disadvantage of fossil fuels exert adverse effect on the environment because many pollutants are formed. Conversely, hydrogen energy resource (H2) burns cleanly, without emitting any environmental pollutants. Further, H2 exists abundantly in the universe and burns with the highest energy content per unit of weight (, kJ/g), comparing to the .