To meet the application needs of rechargeable Zn−air battery and electrocatalytic overall water splitting (EOWS), developing high-efficiency, cost-effective, and durable trifunctional catalysts for the hydrogen evolution reaction (HER), oxygen evolution, and reduction reaction (OER and ORR) is extremely paramount yet challenging. Herein, the interface engineering concept and nanoscale hollowing design were proposed to fabricate N-doping carbon nanoboxes confined with Co/MoC nanoparticles. Uniform zeolitic imidazolate framework nanocube was employed as the starting material to construct the trifunctional electrocatalyst through the conformal polydopamine−Mo layer coating and the subsequent pyrolysis treatment. The Co@IC/MoC@PC catalyst displayed superior electrochemical ORR performances with a positive half-wave potential of 0.875 V and a high limiting current density of 5.89 mA/cm 2 . When practically employed as an electrocatalyst in regenerative Zn−air battery, a high specific capacity of 728 mAh/g, a large peak power density of 221 mW/cm 2 , a high open-circuit voltage of 1.482 V, and a low charge/discharge voltage gap of 0.41 V were obtained. Moreover, its practicability was further exploited by overall water splitting, affording low overpotentials of 277 and 68 mV at 10 mA/cm 2 for the OER and HER in 1 M KOH solution, respectively, and a decent operating potential of 1.57 V for EOWS. Ultraviolet photoelectron spectroscopy and density functional theory calculation revealed that the Co/MoC interface synergistically facilitated the charge-transfer, thereby contributing to the enhancements of electrocatalytic ORR/OER/HER processes. More importantly, this catalyst design concept can offer some interesting prospects for the construction of outstanding trifunctional catalysts toward various energy conversion and storage devices.

Over the past few decades, the design and development of carbon materials have occurred at a rapid pace. In particular, these porous graphene-like carbon nitride materials have received considerable attention due to their superior structures and performances in the energy transformation field. In this review, nitrogenated holey two-dimensional graphene and polymeric carbon nitride will be discussed in depth. The structural properties, synthetic methods, and applications including electrocatalytic reactions, such as hydrogen evolution reaction, oxygen reduction reaction, oxygen evolution reaction, and nitrogen reduction reaction, will be presented in detail. Finally, we will present the outlooks on the current obstacles to the development of carbon nitride materials. This comprehensive understanding will help guide and motivate researchers to develop and modify carbon nitride materials with better properties in the future.

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