Study On The Mechanism Of Adsorption Sensing Of WO 3 Different Active Surface H 2

As one of the most attractive candidate for future fuel and energy carrier,hydrogen?H₂?is dangerous due to its highly explosive possibility with an explosive range of 4%–74.2% and high leakage.And its intrinsic properties of tasteless,colorless and odorless make it dangerous doubly.Rapid and accurate hydrogen detection is always necessary during its production,storage,transportation and use.In this work,density functional theory?DFT?has been used to investigate the H₂ sensing mechanism on hexagonal WO₃?001??110??010?surface.The first chapter summarizes the research status of hydrogen sensor,and the second chapter provides a brief introduction for the theoretical method.In the third chapter,the adsorption of H₂ on hexagonal WO₃?001?surfaces was studied systematically by DFT calculation.According to oxygen concentration varying from high to low,four surfaces including O-terminated surface,and oxygen pre-adsorbed,clean and oxygen vacancy presented WO-terminated surfaces are considered.At O-and oxygen pre-adsorbed WO-terminated surface,H₂ adsorbs on pre-adsorbed O1 c and neighboring O_2c forming H₂ O and hydroxyl with charge transfer of 0.635 e and 0.488 e from molecule to surface.It also indicates that the oxygen of the surface is conducive to h-WO₃ based sensor material for H₂ detection.In the fourth chapter,the adsorption of H₂ on highly reactive hexagonal WO₃?110?surfaces was studied systematically by DFT calculation.Also based on the oxygen concentration relationship,the four faces were considered and chemical adsorption were found on the four sides with high charge transfer up to 0.633 e.Overall,it is confirmed theoretically that all of the four?110?faces can achieve highly effective sensing to H₂,and the highly reactive surface exposure can be a substantially effective way to enhance the sensing ability of material.In the Chapter five we use same method to investigate the adsorption H₂ on the h-WO₃?010?surface by DFT calculations.And similar to the situation of?110?surface,four face can achieve highly effective sensing to H₂.But the energy barrier of the reaction is relatively large,means that the possibility of the reaction is somewhat limitated,and may need to help of external conditions to achieve.