LAUSR

Abstract Formaldehyde (HCHO) molecule adsorption on pure, Pd-doped and Si-doped (10, 0) single wall carbon nanotubes (SWCNTs) was studied by density functional theory (DFT) method. The adsorption energy of HCHO adsorption on Si-doped CNT is the largest, −1.791 eV; and then Pd-doped CNT, −1.171 eV; and pure CNT, −0.351 eV. HCHO molecules are not dissociated for three CNT systems, however, CNT walls all change to different degree. For pure and Pd-doped CNTs, the charges transfer from HCHO to CNTs, however, the sum number of charge change for pure CNT is much smaller (+0.005 e) than that of Pd-doped CNT (+0.226 e). The charges transfer from CNT to HCHO for Si-doped CNT (−0.421 e). The conductivities of CNTs with HCHO molecule adsorption according to their energy gaps between HOMO and LUMO in frontier molecular orbital are in decreasing order of Pd-doped CNT (0.187 eV), Si-doped CNT (0.620 eV), and pure CNT (0.984 eV). This study will provide some scientific guidelines for the application of the doping CNT in detecting HCHO molecules as sensor.