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There is significant anticipation for high-efficiency and cost-effective non-precious metal-based catalysts to advance the industrial application of the anodic oxygen evolution reaction (OER) for hydrogen production. This study introduces an efficient strategy that utilizes ligand-induced metal-organic framework (MOF) building blocks for the synthesis of hollow binary zeolitic imidazolate frameworks 67 (ZIF-67) and Prussian blue analogues (PBAs) (ZIF-67@PBA) heterostructures through a hybrid MOF-on-MOF approach. Manipulating the Co 2+ /Zn 2+ ratio in the precursor ZIF-67 allows for the convenient synthesis of the final product, denoted as Co x Fe-ZP, after pyrolysis, where the inclusion of Zn effectively modulates the distribution of Co in the catalyst. The resulting Co x Fe-ZP catalysts exhibit a positive synergistic effect between hollow graphitic carbon nanomaterials and Fe-doped Co nanoparticles. The optimal Co 0.3 Fe-ZP catalyst demonstrates satisfactory OER performance, achieving an overpotential of 302 mV at 10 mA cm -2 and a small Tafel slope of 60.0 mV dec -1 . Further analysis of the activation energy confirms that the enhanced OER activity of Co 0.3 Fe-ZP can be reasonably attributed to the combined influence of its morphology and composition. This study demonstrates a ligand-induced method for examining the morphology and electrochemical properties of grown binary MOF-on-MOF heterostructures for OER applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Cobalt-entrapped, nitrogen-doped mesoporous carbon materials have been prepared using melamine formaldehyde resin (MF resin) as precursor and CoCl 2 as template. A fraction of CoCl 2 can be reduced to Co nanoparticles and wrapped by the nitrogen doped carbon. Meanwhile, the ratio of MF resin to CoCl 2 is an important parameter determining the mesoporous structures of the final products. The surface area of the obtained material decreases with the increase in the ratio of MF resin to CoCl 2 . Electrocatalytic tests show that the obtained catalysts are highly active for hydrogen evolution reaction in both acidic and basic media, achieving a current density of 10 mA cm -2 at 171 and 186 mV under acidic and alkaline conditions, respectively. Additionally, these catalysts also show good long-term stabilities., (Copyright © 2018 Elsevier Inc. All rights reserved.)