First-principles study of gas adsorption and sensing based on noble metal (Ag, Au and Pt) - Decorated α-AsP monolayer

Abstract

The adsorption behaviors of five small gas molecules (NO, NO2, CO, CO2 and H2O) adsorbed on noble metal (Ag, Au and Pt) - decorated black arsenic phosphorous (α-AsP) was researched using first-principles calculation. The structural optimization models, electronic properties, adsorption, and sensing properties of noble metals-decorated AsP monolayer after adsorbing these gas molecules was methodically discussed. The results show that noble metal absorbing can excessively improve the adsorption ability of α-AsP structure. Meanwhile, the Pt-decorated AsP system exhibits its maximum adsorption energy towards CO of −1.911 eV, for all gas adsorption on the noble metal decorated systems. Especially, the Pt-decorated AsP system has high adsorbability to NO with adsorption energy of −1.442 eV, which is over 18 times larger than the pristine α-AsP monolayer. Moreover, the selectivity and desorption are key factors of gas sensor materials. The most suitable gas sensing system is the Ag-decorated AsP monolayer with the corresponding adsorption energy and recovery time toward NO of −0.608 eV, 0.016 s and CO of −0.770 eV, 8.580 s, respectively. We strongly believe that Ag-decorated AsP can be utilized as potential NO and CO gas sensor.