Density Functional Theory Calculations Of Ti-based MIXenes Materials For Detecting Breath Biomarkers Of Chronic Disease

Chronic diseases patients will produce iconic volatile organic gases(VOCs)through abnormal metabolism and be exhaled by the human body.Early non-destructive screening for chronic diseases patients can be achieved by detecting the types and contents of VOCs.Therefore,the development of gas sensitive detection materials with high selectivity and high sensitivity for VOCs will effectively promote the normalization of early chronic disease screening.MXenes are the general term for transition metal carbides or nitrides.As an emerging two-dimensional material,MXenes have attracted much attention in recent years due to their unique structure and adjustable properties.Ti-based MXenes are widely studied.Among them,Ti2C has a large specific surface area,Ti3CN contains the characteristics of TiC and TiN,and TiNbC combines the structure and properties of Ti2C and Nb2C,so they all have great research potential.In this paper,considering the van der Waals force correction,the first-principles calculation method based on density functional theory is used to study the gas sensing properties and detection potential of Ti2C,Ti3CN and TiNbC nanosheets for chronic disease breath biomarkers.And vacancies and doping defects are introduced to explore their effects on the gas sensing properties of materials.The main research contents of this paper are as follows:For the lung cancer breath biomarker ethylbenzene,pristine and vacancy Ti2C,Ti3CN and TiNbC show good selectivity and sensitivity,and have good detection potential.The existence of vacancies generally enhances the adsorption energy of matrixs for ethylbenzene,thereby improving the selectivity of ethylbenzene.The adsorption energy of vacancy TiNbC systems are the highest,which is 12%-28%higher than that of the pristine system.The vacancy defects change the charge transfers by controlling the number of electron donors,which affects the sensitivity of ethylbenzene.The charge transfers of N-vacancy Ti3CN and C-vacancy TiNbC systems are 21%and 5%higher than that of their respective pristine systems.Therefore,the sensitivity is significantly improved.For the diabetic breath biomarker acetone,Ti3CN and TiNbC nanosheets show excellent detection potential.The vacancy defects generally enhance the selectivity of Ti3CN and TiNbC nanosheets to acetone,and the adsorption energys increase by 3%-10%and 3.5%-13%compared with their respective pristine systems.In terms of sensitivity,the C vacancy systems of Ti3CN and TiNbC perform best,and the charge transfers are 18%and 13%higher than that of their respective pristine systems.The introduction of doping atoms will slightly increase the sensitivity of Ti3CN to acetone and the selectivity of TiNbC to acetone.Among them,the charge transfers of the N-B system of Ti3CN is 1.7 times that of the pristine system.And the adsorption energy of the Ti-Zr system of TiNbC is 1.3 times that of the pristine system.For the liver cirrhosis breath biomarker dimethyl sulfide(DMS),pristine and defective Ti3CN nanosheets are ideal detection substrates,showing good selectivity,sensitivity and adsorption stability for DMS.The vacancy defects mainly enhance the sensitivity of Ti3CN to DMS.The charge transfers of the vacancy Ti3CN systems increase by 3%-23%compared with the pristine system.The Ti-Zr system in the doped Ti3CN systems shows good detection potential for DMS.The adsorption energy of the system is 4%higher than that of the pristine system,and the charge transfers are the same as that of the pristine system.