High efficient and non-precious metal electrocatalysts for oxygen evolution reactions (OER) and oxygen reduction reactions (ORR) are at the heart of key renewable-energy technologies. Nevertheless, developing highly-active bi-functional catalysts at low cost for both OER and ORR still remains a huge challenge. In this paper, Co3O4 nanocrystals embedded in N-doped mesoporous graphitic carbon layer/multiwalled carbon nanotubes (MWCNTs) hybrids are prepared by a facile carbonization and subsequent oxidation process of MWCNTs-based metal-organic framework (MOF). As a result, in alkaline media, the hybrid material catalyzes OER with an onset potential of 1.50 V (vs reversible hydrogen electrode) and over-potential only of 320 mV to achieve a stable current density of 10 mA cm -2 for at least 25 h. The same hybrids also exhibit similar catalytic activity but superior stability to commercial 20 wt% Pt/C catalyst for ORR, making it a high-performance cheap bi-catalyst for both OER and ORR. The design concept of nonmetal-doped and precious-metal-free electrocatalysts from MOF can be extended to fabricate other novel, stable and easy to use catalyst system for advanced applications.

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Achieving large‐sized and thinly layered 2D metal phosphorus trichalcogenides with high quality and yield has been an urgent quest due to extraordinary physical/chemical characteristics for multiple applications. Nevertheless, current preparation methodologies suffer from uncontrolled thicknesses, uneven morphologies and area distributions, long processing times, and inferior quality. Here, a sonication‐free and fast (in minutes) electrochemical cathodic exfoliation approach is reported that can prepare large‐sized (typically ≈150 µm2) and thinly layered (≈70% monolayer) NiPS3 flakes with high crystallinity and pure phase structure with a yield ≈80%. During the electrochemical exfoliation process, the tetra‐n‐butylammonium salt with a large ionic diameter is decomposed into gaseous species after the intercalation and efficiently expands the tightly stratified bulk NiPS3 crystals, as revealed by in situ and ex situ characterizations. Atomically thin NiPS3 flakes can be obtained by slight manual shaking rather than sonication, which largely preserves in‐plane structural integrity with large size and minimum damage. The obtained high quality NiPS3 offers a new and ideal model for overall water splitting due to its inherent fully exposed S and P atoms that are often the active sites for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Consequently, the bifunctional NiPS3 exhibits outstanding performance for overall water splitting.