Theoretical Investigation On The Adsorption Mechanism Of Typical VOCs Onto New Two-dimensional Material C₂N

Volatile organic compounds?VOCs?are one kind of air pollutants,which seriously affect ecological environment and threaten human health.In the field of pollution remediation,adsorption has the advantages of being simple and low-cost with a wide application range and high efficiency,so that it is widely used for the removal and separation of VOCs in industry and internal living areas.What's more,due to the advantages of strong oxidation ability,small selectivity,mild reaction conditions and without secondary pollution,the semiconductor photocatalysis has attracted considerable research attention in the past few decades.In this work,the adsorption and potential catalytic oxidation performance of Al-doped C₂N system were studied by density functional theory?DFT?,which can be beneficial to the design and development of high performance photocatalyst.The main outputs are shown as follow:?1?Adsorption properties of Al-doped C₂N:The adsorption capacity of three typical VOCs molecules?HC HO,C₆H₆ and C₂HCl₃?adsorbed onto pristine/Al-doped C₂N system are investigated.The results demonstrate that these three VOCs can be absorbed onto pristine C₂N monolayer with weak adsorption energy,while the adsorption ability can be improved with the formation of strong chemical bond between the VOCs molecules and the Al-doped C₂N layer.Especially for the formaldehyde molecule,the adsorption energy is obtained as-2.754 eV,which nearly 5 times larger than that of pristine C₂N system.Moreover,the PDOS,Mulliken population analysis and electronic distribution are calculated to study the adsorption enhancement mechanism.The results show that doped Al atom can act as a bridge to link VOCs molecules with C₂N monolayer and strengthen their interaction,which can significantly enhance the adsorption capacity for VOCs molecules.Therefore,Al doped C₂N monolayer is shown to be a promising adsorbent for VOCs enriching and utilization.?2?Photocatalytic performance of Al-doped C₂N:firstly,the calculated band structure shows that Al-doped C₂N has the potential for the transformation of oxygen to superoxide radical,and it can reduce the width of band gap,which is advantageous to the transition of valence band electrons.Besides,we have calculated the adsorption properties of oxygen molecules onto Al doped C₂N and the results show that the dopant Al atom can effectively improve the oxygen adsorption ability of the system.What's more,the calculated optical property demonstrate that the doped system provide a stronger responsive within visible and infrared region,which can improve the ability to absorb the solar energy.Therefore,Al doped C₂N is shown to be a promising potential photocatalytic material for the degradation of organic contaminant.?3?Adsorption and catalytic degradation for HCHO molecule onto Al-decorated C₂N:The adsorption energy of HCHO on Al-decorated C₂N monolayer is-2.586 eV,which can reach the enrichment of HCHO molecules compared with the pristine C₂N system.Moreover,water and oxygen molecules can also strongly adsorbed on Al-decorated C₂N monolayer,which provides a good basis and condition for the formation of free radicals with oxidation ability on the surface.Our findings suggest that Al-decorated C₂N is expected to be a promising material for the adsorption and catalytic degradation of HCHO molecules.