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Molybdenum disulfide (MoS 2 ) is considered as a promising candidate to Pt-based catalysts. Literatures report the active centers of MoS 2 locate at its edges, while the perfect in-plane domains are not active. In this study, a simple Co Mo S precursor decomposition approach is used to synthesize Co-doped MoS 2 in-situ grown graphite paper (GP) substrate. Electrochemical analyses reveal the Co-doped MoS 2 possesses excellent electrocatalytic activity comparable to Pt. Density functional theory (DFT) calculations indicate the inert in-plane S atoms neighboring the doped Co atoms become active towards triiodide reduction, as revealed by the adsorption energies ( E ad ) of iodine atom decreasing from 0.36 eV to −0.52 eV, identical with value obtained from Pt (−0.52 eV). Due to increased active sites, highly conductive of GP, and excellent electrical connection between Co-doped MoS 2 and GP substrate, the dye-sensitized solar cell fabricated using Co-doped MoS 2 /GP as counter electrode (CE) shows higher photoelectric conversion efficiency (7.26%) than those based on MoS 2 /GP CE (6.57%) and platinized F-doped tin oxide (Pt/FTO) electrode (6.87%). [ABSTRACT FROM AUTHOR]

The paper focuses on theoretical and experimental aspects of an oxide surface optimization for oxygen reduction reaction (ORR). Various doped α-MnO 2 based electrocatalysts were prepared by microwave-assisted hydrothermal synthesis and electrochemically characterized to validate density functional theory (DFT) based predictions of the oxidation state and local structure effects on the catalytic activity of α-MnO 2 catalysts in ORR. Both theory and experiments conclude that the highest activity in ORR is to be expected in the case of clustered Mn 3+ sites which yield activity comparable with that of the polycrystalline Pt. These active sites have to be formed under in-operando conditions and their formation is hindered in doped α-MnO 2 catalysts. The activity of the other conceivable active sites based on non-clustered Mn 3+ or Mn 4+ is inferior to that of clustered Mn 3+ . The activation of Mn 3+ or Mn 4+ based active sites leads to a shift in selectivity of the ORR process towards 2 electron formation of hydrogen peroxide. [ABSTRACT FROM AUTHOR]