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Highly efficient and stable dual-function electrocatalysts for overall water splitting are of great significance to promote the application of hydrogen energy. Constructing a bimetallic phosphide nanocomposite structure can enhance active sites and accelerate electron transfer, which is beneficial to electrocatalysis. Herein, we obtained self-supporting cobalt-iron phosphide nanosheets supported on foamed nickel through twostep hydrothermal and phosphating treatment. When the CoFe-P/ NF-1 electrode material reaches 100 mA cm −2 , only a HER overpotential of 180 mV is required. Moreover, the overpotential for OER is 275 mV at 200 mA cm −2 . The overall water splitting electrolyzer assembled by CoFe-P/NF-1 can reach a current of 10 mA cm −2 at 1.57 V. The catalytic performance is better than the currently reported transition metal-based catalysts, and it exhibits excellent stability. This work provides a design idea of transition metal phosphide used in overall water splitting catalysis.

A sandwich shelled hollow TiO2@Co3O4@Co3O4/C composite is synthesized by consecutive coating of Co3O4 nanosheets and TiO2 particles on Co3O4/C hollow spheres.

Metal−organic framework (MOF)-derived materials have attracted increasing attention in the field of energy storage and conversion. Calcining MOFs to carbonized structures is a common route to obtain MOF-derived materials. However, the existing calcination conditions often cause the structural collapse and the specific surface area to be significantly reduced. In this work, we use argon−hydrogen mixed gas for calcination of MOFs to obtain a N-doped porous carbon material with excellent properties. Its BET specific surface area and pore volume up to 2476 m 2 g −1 and 1.325 cm 3 g −1 , respectively, which are higher than those of the precursor ZIF-8 (1960 m 2 g −1 and 0.687 cm 3 g −1 ), perfectly inherited the rhombic dodecahedron morphology of the precursor. Hydrogen reduces the zinc in ZIF-8 at high temperature to evaporate, which avoids the carbothermal reduction reaction between the zinc component and the carbon framework of MOFs, protecting the framework of MOFs and leaving a lot of micropores, so that after the carbonization of MOFs it still has extremely high specific surface area and pore volume, even surpassing the MOFs precursors. We loaded Pt nanoparticles on the prepared porous carbon to catalyze the oxygen reduction reaction and showed an excellent half-wave potential of 0.883 V, which is 10 mV higher than that of the commercial Pt/C (Pt 20 wt %), while the Pt loading is only 8.66 wt %. The stability is also much better than Pt/C.