The regulation of electron distribution of single-atomic metal sites by atomic clusters is an effective strategy to boost their intrinsic activity of oxygen reduction reaction (ORR). Herein we report the construction of single-atomic Mn sites decorated with atomic clusters by an innovative combination of post-adsorption and secondary pyrolysis. The X-ray absorption spectroscopy confirms the formation of Mn sites via Mn-N 4 coordination bonding to FeMn atomic clusters (FeMn ac /Mn-N 4 C), which has been demonstrated theoretically to be conducive to the adsorption of molecular O 2 and the break of OÀ O bond during the ORR process. Benefiting from the structural features above, the FeMn ac /Mn-N 4 C catalyst exhibits excellent ORR activity with half-wave potential of 0.79 V in 0.5 M H 2 SO 4 and 0.90 V in 0.1 M KOH as well as preeminent Zn-air battery performance. Such synthetic strategy may open up a route to construct highly active catalysts with tunable atomic structures for diverse applications.
The development of highly efficient and cost‐effective hydrogen evolution reaction (HER) catalysts is highly desirable to efficiently promote the HER process, especially under alkaline condition. Herein, a polyoxometalates‐organic‐complex‐induced carbonization method is developed to construct MoO2/Mo3P/Mo2C triple‐interface heterojunction encapsulated into nitrogen‐doped carbon with urchin‐like structure using ammonium phosphomolybdate and dopamine. Furthermore, the mass ratio of dopamine and ammonium phosphomolybdate is found critical for the successful formation of such triple‐interface heterojunction. Theoretical calculation results demonstrate that such triple‐interface heterojunctions possess thermodynamically favorable water dissociation Gibbs free energy (ΔGH2O) of ‐1.28 eV and hydrogen adsorption Gibbs free energy (ΔGH*) of ‐0.41 eV due to the synergistic effect of Mo2C and Mo3P as water dissociation site and H* adsorption/desorption sites during the HER process in comparison to the corresponding single components. Notably, the optimal heterostructures exhibit the highest HER activity with the low overpotential of 69 mV at the current density of 10 mA cm−2 and a small Tafel slope of 60.4 mV dec−1 as well as good long‐term stability for 125 h. Such remarkable results have been theoretically and experimentally proven to be due to the synergistic effect between the unique heterostructures and the encapsulated nitrogen‐doped carbon.
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