摘要：Phosphorus doped MoS2 nanosheets (P-doped MoS2) have been reported as excellent oxygen reduction reaction (ORR) catalysts with four-electron selectivity in alkaline solution. By performing density functional theory (DFT) calculations, we revealed the detailed reaction mechanism and the key reaction sites on surface of P-doped MoS2 for ORR catalysis. The double P-doped MoS2 (2P-MoS2) is calculated to be more stable than the single P-doped MoS2 (P-MoS2), and the configuration with two P atoms in neighboring sites exhibits the highest stability. The surface of P-doped MoS2 is found highly active for dissociation of O2. Comparative calculations reveal that P-MoS2 is unsuitable as ORR catalyst due to the high dissociation barrier of H2O (1.19 and 2.06 eV for the first and second adsorbed H2O), while the 2P-MoS2 shows good ORR catalytic activity with much lower dissociation barrier of H2O (0.62 eV). Furthermore, we elucidated that the ORR catalytic activity in 2P-MoS2 originates from the activated S2 atom, which provides an extra adsorption site for the first H2O and the following OH group benefited from the enhanced hydrogen bond interaction. Our results illustrate the mechanisms of doped MoS2 based catalysts and provide rational way for designing ORR catalysts with high activity.
