Developing
bifunctional electrocatalysts for oxygen evolution reaction
(OER) and hydrogen evolution reaction (HER) toward overall water splitting
with high efficiency and robust durability is highly desirable but
very challenging. Herein, we report a highly efficient and robust
bifunctional electrocatalyst for overall water splitting based on
Co@Ir core–shell nanoparticles encapsulated in nitrogen-doped
porous carbon derived from metal–organic frameworks. The series
of Co@Ir/NC-x samples were prepared through a galvanic
replacement of IrCl3 with Co/NC, which was obtained by
calcination of zeolitic imidazolate framework 67 (ZIF-67). In the
electrocatalytic characterizations toward OER and HER, Co@Ir/NC-10%
exhibited the best performance among the series, with an overpotential
of 280 mV at a current density of 10 mA cm–2 for
OER, superior to the benchmark IrO2 catalyst, and an overpotential
of −121 mV at a current density of 10 mA cm–2 for HER in 1 M KOH. Moreover, Co@Ir/NC-10% also demonstrated markedly
higher long-term stability than IrO2 for OER and superior
long-term durability than Pt/C for HER. Finally, the overall water
splitting catalyzed by the series of composites was explored and visually
observed.
HIGHLIGHTS • A facile strategy for fabricating Ni x Co 1−x Se hollow nanocages was developed, and the formation mechanism was well explained. • Ni 0.2 Co 0.8 Se outperformed a Pt/C + RuO 2 catalyst in rechargeable and all-solid-state Zn-air battery tests, as well as in overall water splitting. • The hydrogen adsorption onto Ni x Co 1−x Se was simulated, and Gibbs free energies were calculated.
The recognition of
the solid electrolyte interface (SEI) between the electrode materials
and electrolyte is limiting the selection of electrode materials,
electrolytes, and further the electrochemical performance of batteries.
Herein, we report ZnSe@C core–shell nanocomposites derived
from ZIF-8 as anode materials of lithium-ion batteries, the electrochemical
performances, and SEI films formed on ZnSe@C in both ether and carbonate
electrolytes. It is found that ZnSe@C delivers a reversible capacity
of 617.1 mA h·g–1 after 800 cycles at 1 A·g–1 in the ether electrolyte, much higher than that in
the carbonate electrolyte. Both ex situ X-ray diffraction and X-ray
photoelectron spectroscopies reveal that stable SEI films are formed
on ZnSe@C in the ether electrolyte while selenium is involved in the
formation of SEI films and further dissolved into the carbonate electrolyte
because of the concurrent decomposition of electrolytes and insertion
of Li+ into ZnSe, which differentiates between the cycling
performances of ZnSe@C composites in ether and carbonate electrolytes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.