Density Functional Theory Study And Analysis Of M₄/TiO₂ Catalyzed Methane Reforming Reaction

The development and utilization of natural gas is one of the important research topics in the energy and chemical industry field,therein,the catalytic reforming of methane forming syngas has been widely applied in industry.However,the more mature catalysts for the catalytic reforming of methane usually face various problems,which include the losing and sintering of active components,carbon accumulation,large energy consumption,severe reaction conditions,etc.The traditional experimental technology has been developed very well,but it is still necessary to deeply study the mechanism of catalyst for methane reforming reaction theoretically.Exploring adsorption,activation,selectivity,and mechanism in the catalytic reforming of methane by theoretical calculations is an important guiding ideology for the design of new high-efficiency catalysts.This paper focuses on the catalysts with non-noble metal clusters of Ni and Co supported on the TiO₂(110)surface,and the following research work has been carried out:1.Density functional theory(DFT)calculations with a Hubbard U correction was performed to study methane reforming reaction catalyzed by Ni₄/TiO₂(110)and Co₄/TiO₂(110),selecting rutile TiO₂(110)surface as the supporter,and calculating the optimal adsorption position of the Ni₄ and Co₄ metal clusters based on the periodicity and atomic coordination.The stable adsorption configuration was selected as the catalyst model to calculate the density of states(DOS)information of each atom in the metal cluster,and the activity difference between these atoms was compared.The optimum adsorption configuration and adsorption energy of the relevant species for the catalytic reforming of methane on M₄/TiO₂(110)surface were calculated,and the adsorption ability distinctions of different species on the surface catalyst were compared,and the effective relationship of orbits between adsorption species and supporter was further calculated,and the selectivity of product influenced by the interaction between catalyst and reactive species was elaborated.2.Based on the method of CI-NEB for searching the transition state,DFT was employed to investigate the micro-mechanism of methane reforming reaction on Ni₄/TiO₂(110)and Co₄/TiO₂(110)surfaces,and drawing the graph of reactive potential energy.The differences between Co₄/TiO₂(110)and Ni₄/TiO₂(110)on methane activation and carbon deposition resistance were compared through analyzing the rule of potential energy,and the reasons were analyzed in detail.3.On the basis of above data,combining with the reaction path,multiple property were analyzed(partial density of states analysis,local density of states analysis,Bader charge analysis,crystal orbital Hamilton population analysis,barrier decomposition analysis),which further explore the structure-activity relationship bewteen M₄/TiO₂ catalysts and methane reforming reaction.