▎ 摘　　要

We perform a comparative theoretical study of benzene and its homologues (toluene, para-xylene, and mesitylene) adsorbed on Cu/Al/Pd(111)-supported graphene using density functional theory (DFT). The long-range attraction is handled by semiempirical dispersion correction method (PBE-D3) and ab initio van der Waals density functionals (vdW-DF2, optB86b-vdW, optB88-vdW, and SCAN-rVV10). Our results show a systematic increase in the adsorption energy of organic molecules on graphene in the presence of underlaying metal substrates. In the case of strong metal-graphene contact, such as Pd(111)-graphene, the adsorption energy of benzene even increases 0.44 eV, which presents suitable platform for filtering harmful molecules such as benzene. Besides, we find out that the dispersion-corrected functionals play a fundamental role in the structure and adsorption energy. Furthermore, the adsorption energy increases linearly with the number of methyl groups on the benzene ring.