Constructing an efficient alkaline hydrogen evolution reaction (HER) catalyst with low platinum (Pt) consumption is crucial for the cost reduction of energy devices, such as electrolyzers. Herein, nanoflower‐like carbon‐encapsulated CoNiPt alloy catalysts with composition segregation are designed by pyrolyzing morphology‐controlled and Pt‐proportion‐tuned metal–organic frameworks (MOFs). The optimized catalyst containing 15% CoNiPt NFs (15%: Pt mass percentage, NFs: nanoflowers) exhibits outstanding alkaline HER performance with a low overpotential of 25 mV at a current density of 10 mA cm−2, far outperforming those of commercial Pt/C (47 mV) and the most advanced catalysts. Such superior activity originates from an integration of segregation alloy and Co‐O hybridization. The nanoflower‐like hierarchical structure guarantees the full exposure of segregation alloy sites. Density functional theory calculations suggest that the segregation alloy components not only promote water dissociation but also facilitate the hydrogen adsorption process, synergistically accelerating the kinetics of alkaline HER. In addition, the activity of alkaline HER is volcanically distributed with the surface oxygen content, mainly in the form of Co3dO2p hybridization, which is another reason for enhanced activity. This work provides feasible insights into the design of cost‐effective alkaline HER catalysts by coordinating kinetic reaction sites at segregation alloy and adjusting the appropriate oxygen content.

BiOCl as a two-dimensional layer ternary oxide semiconductor, has been widely used in energy and environmental area due to its non-toxicity, price and the good photocatalytic performance. However, BiOCl has a wide bandgap and can only absorb ultraviolet light, which limits its solar energy conversion efficiency for practical application. Herein, we report a facile synthesis of FeOOH/BiOCl nanocomposites by hydrothermal method. The results of XPS and FT-IR * J. Gao E-Mail: jkgao@zstu.edu.cn [a] Institute of Fiber based New Energy Materials

Hydrogen production from water splitting is one of the effective methods to solve energy and environmental problems. However, the large overpotential of oxygen evolution reactions (OER) seriously impedes their development and application. Therefore, it is crucial to find a catalyst with low cost and high stability for OER. Herein, we report a simple method to fabricate a series of porous catalysts encapsulated with Co 3 O 4 nanoparticles by carbonizing and then oxidizing MOF precursors, which can regulate and produce a large number of oxygen vacancies. The overpotentials of Z67-Co 3 O 4 /C-4 and Z9-Co 3 O 4 /C-4 are only 353and 349 mV at a current density of 10 mA cm À 2 with a small Tafel slope of 60 and 67 mV dec À 1 , respectively. These excellent properties can be attributed to the graphite carbon and unique hollow structure, as well as more water molecules adsorbed by oxygen vacancies, which effectively improve the conductivity and electron transfer and further promote OER activity. Thus, this preparation strategy can be applied to various MOF catalysts to regulate oxygen vacancies and thereby expanding their application in a wider range of fields.

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