Hydrogen produced from electrocatalytic water splitting is a promising route due to the sustainable powers derived from the solar and wind energy. However, the sluggish kinetics at the anode for water splitting makes the highly effective and inexpensive electrocatalysts desirable in oxygen evolution reaction (OER) by structure and composition modulations. Metal-organic frameworks (MOFs) have been intensively used as the templates/precursors to synthesize complex hollow structures for various energy-related applications. Herein, an effective and facile template-engaged strategy originated from bimetal MOFs is developed to construct hollow microcubes assembled by interconnected nanopolyhedron, consisting of intimately dominant FeNi alloys coupled with a small NiFeO oxide, which was confined within carbonitride outer shell (denoted as FeNi/NiFeO@NC) via one-step annealing treatment. The optimized FeNi/NiFeO@NC exhibits excellent electrocatalytic performances toward OER in alkaline media, showing 10 mA·cm at η = 316 mV, lower Tafel slope (60 mV·dec), and excellent durability without decay after 5000 CV cycles, which also surpasses the IrO catalyst and most of non-noble catalysts in the OER, demonstrating a great perspective. The superior OER performance is ascribed to the hollow interior for fast mass transport, in situ formed strong coupling between FeNi alloys and NiFeO for electron transfer, and the protection of carbonitride layers for long stability.

Replacement of precious platinum with efficient and low-cost catalysts for electrocatalytic hydrogen evolution reaction (HER) at low overpotentials holds tremendous promise for clean energy devices. Herein, molybdenum polysulfide (MoS x ) anchored on a porous Zr-metal organic framework (Zr-MOF, UiO-66-NH 2 ) by chemical interactions is fabricated by a facile and one-pot solvothermal method for HER application. The distinctive design of the Zr-MOF stabilized MoS x composite enables remarkable electrochemical HER activity with a Tafel slope of 59 mV•dec −1 , a lower onset potential of nearly 125 mV, and a cathode current of 10 mA•cm −2 at an overpotential of 200 mV, which also exhibits excellent durability in an acid medium. The superior HER performance should ascribe to the fast electron transport from the less conducting MoS x nanosheets to the electrode, high effective surface area, and number of active sites, as well as the favorable delivery for local protons in the porous Zr-MOF structure during the electrocatalytic reaction. Thus, this work paves a potential pathway for designing efficient Mo-based HER electrocatalysts by the combination of molybdenum polysulfide and versatile proton-conductive MOFs.

Morphology-controlled synthesis of metal− organic frameworks (MOFs) is of tremendous importance to understand the morphology−structure−property relationships. Although great emphasis has been placed on the controllable synthesis of MOFs, the preparation of hollow and nanoframelike MOFs, especially using the microwave irradiation method, remains a great challenge. In the present work, we report microwave-assisted synthesis of hollow butterfly and ring zeolitic imidazolate framework-8 (ZIF-8) with the stimuli of Ni ions. Interestingly, the sphere, butterfly, and fiber ZIF-8 catalysts were also fabricated when adjusting the weight ratio of Zn and Ni resources. Specifically, sphere, butterfly, hollow butterfly, and ring particles have maintained the ZIF-8 structure. On the basis of the time sequential experiments, we inferred that the formation of hollow butterfly and ring particles is driven by the change of surface energy. The Knoevenagel reaction was carried out to explore the catalytic activity of these ZIF materials. The ring particles with ZIF-8 structure showed the highest catalytic activity. The open structure, thin walls, and the amount of basicity have been extensively discussed to shed light on the superior catalytic performance of ring particles.

Multiply-twinned Au–Ag NCs/rGO are prepared by a one-pot method under microwave irradiation and exhibit excellent HER activity and stability.

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