Borohydrides have been recently hightlighted as prospective new materials due to their high gravimetric capacities for hydrogen storage. It is, therefore, important to under- stand the underlying dehydrogenation mecha...Borohydrides have been recently hightlighted as prospective new materials due to their high gravimetric capacities for hydrogen storage. It is, therefore, important to under- stand the underlying dehydrogenation mechanisms for further development of these ma- terials. We present a systematic theoretical investigation on the dehydrogenation mecha- nisms of the Mg2（BH4）2（NH2）2 compounds. We found that dehydrogenation takes place most likely via the intermolecular process, which is favorable both kinetically and thermo- dynamically in comparison with that of the intramolecular process. The dehydrogenation of Mg2（BH4）2（NH2）2 initially takes place via the direct combination of the hydridie H in BH4 and the protie H in NH2-, followed by the formation of Mg-H and subsequent ionic recombination of Mg-Hδ-…Hδ＋-N.展开更多
Designing high active,low cost and bifunctional electrocatalysts is urgent for developing clean energy storage and conversion systems.Transition metal selenides exhibit optimal electronic conductivity and tunable phys...Designing high active,low cost and bifunctional electrocatalysts is urgent for developing clean energy storage and conversion systems.Transition metal selenides exhibit optimal electronic conductivity and tunable physicochemical properties,which endow them with potential for efficient electrocatalysts to facilitate the oxygen reduction and oxygen evolution reactions(ORR and OER).Herein,hollow NixCo0.85-xSe nanospheres were synthesized using a facile polyol based solution chemical method.The NixCo0.85-xSe exhibits an onset overpotential of 0.89 V for ORR,and an overpotential of 305 mV to achieve 10 mA cm^-2 for OER.Moreover,the NixCo0.85-xSe based Zn-air battery displays remarkable specific capacity and durability.Such superior catalytic performances can be attributed to the synergistic effect,large specific surface area and enhanced electron transfer rate.This approach provides a new way to design highly efficient bifunctional electrocatalysts for electrochemical energy storage and utilization.展开更多
文摘Borohydrides have been recently hightlighted as prospective new materials due to their high gravimetric capacities for hydrogen storage. It is, therefore, important to under- stand the underlying dehydrogenation mechanisms for further development of these ma- terials. We present a systematic theoretical investigation on the dehydrogenation mecha- nisms of the Mg2（BH4）2（NH2）2 compounds. We found that dehydrogenation takes place most likely via the intermolecular process, which is favorable both kinetically and thermo- dynamically in comparison with that of the intramolecular process. The dehydrogenation of Mg2（BH4）2（NH2）2 initially takes place via the direct combination of the hydridie H in BH4 and the protie H in NH2-, followed by the formation of Mg-H and subsequent ionic recombination of Mg-Hδ-…Hδ＋-N.
基金supported by the National Natural Science Foundation of China (51804216)a scholarship from the China Scholarship Council (CSC) (201806255078)
文摘Designing high active,low cost and bifunctional electrocatalysts is urgent for developing clean energy storage and conversion systems.Transition metal selenides exhibit optimal electronic conductivity and tunable physicochemical properties,which endow them with potential for efficient electrocatalysts to facilitate the oxygen reduction and oxygen evolution reactions(ORR and OER).Herein,hollow NixCo0.85-xSe nanospheres were synthesized using a facile polyol based solution chemical method.The NixCo0.85-xSe exhibits an onset overpotential of 0.89 V for ORR,and an overpotential of 305 mV to achieve 10 mA cm^-2 for OER.Moreover,the NixCo0.85-xSe based Zn-air battery displays remarkable specific capacity and durability.Such superior catalytic performances can be attributed to the synergistic effect,large specific surface area and enhanced electron transfer rate.This approach provides a new way to design highly efficient bifunctional electrocatalysts for electrochemical energy storage and utilization.
