Single noble metals (Pd, Pt and Ir) anchored Janus MoSSe monolayers: Efficient oxygen reduction/evolution reaction bifunctional electrocatalysts and harmful gas detectors

Abstract

The binding properties of single noble metal atoms (Pd, Pt and Ir) anchored Janus MoSSe monolayers (MLs), the catalytic activity of Pd- and Pt-MoSSe in oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as well as the adsorption behaviors of Ir-MoSSe for harmful NO, CO and NH3 molecules are systematically studied from the first-principles calculations. Current results reflect the ascending order (Pd-MoSSe < Pt-MoSSe < Ir-MoSSe) of stability and binding strength as well as the tunable electronic properties of Janus MoSSe ML by anchoring single Pd, Pt and Ir atoms. Pd- and Pt-MoSSe exhibit excellent bifunctional catalytic performance, especially the former having lower overpotentials 0.43 and 0.50 V for ORR and OER, which are better than the well-known Pt (111) (0.45 V) and IrO2 (0.56 V) electrocatalysts, respectively. The adsorption nature for NO, CO and NH3 molecules changes from physisorption (on pristine MoSSe) to chemisorption (on Ir-MoSSe), especially for NO and CO molecules due to their ultra-low adsorption energies (−3.72 and −2.91 eV, respectively). Thus, Pd- and Pt-MoSSe (particularly the former) may act as promising highly-efficient ORR/OER bifunctional electrocatalysts, and Ir-MoSSe may serve as a potential sensitive harmful gas detector for NO and CO molecules.