Implanted metal-nitrogen active sites enhance the electrocatalytic activity of zeolitic imidazolate zinc framework-derived porous carbon for the hydrogen evolution reaction in acidic and alkaline media

Developing electrocatalysts with excellent catalytic performance and superior durability for hydrogen evo-lution reaction (HER) remains a challenge. Herein, metal-nitrogen sites (M-N-x, M = Ni and Cu) are success-fully implanted into zeolitic imidazolate zinc framework (ZIF-8)-derived nitrogen-doped porous carbon (ZIF/NC) to prepare Ni-ZIF/NC and Cu-ZIF/NC electrocatalysts for the HER. These M-Nx active sites significantly enhanced the electrocatalytic activities of Ni-ZIF/NC and Cu-ZIF/NC. Metal Ni acted as a catalyst for catalysis of Ni-ZIF/NC to form carbon nanotubes-like structures, which provided convenient ion transmis-sion pathways. Owing to its special morphology and an increased number of defects, Ni-ZIF/NC displayed superior electrocatalytic activity in the HER compared to those of Cu-ZIF/NC and ZIF/NC. In an alkaline environment, Ni-ZIF/NC exhibited an overpotential at the current density of 10 mA cm(-2) (eta(10)) of 163.0 mV and Tafel slope of 85.0 mV dec(-1), demonstrating an electrocatalytic property equivalent to that of Pt/C. In an acidic environment, Ni-ZIF/NC yielded a tr10 of 177.4 mV and Tafel slope of 83.9 mV dec(-1), which were comparable to those of 20 wt.% Pt/C. Moreover, Ni-ZIF/NC and Cu-ZIF/NC also exhibited superior stabilities in alkaline environments. This work offers a valuable strategy for controlling the morphology and implanting M-Nx active sites into carbon for designing novel catalysts for use in alternative new energy applications. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

The study successfully implanted metal-nitrogen sites into carbon materials to prepare Ni-ZIF/NC and Cu-ZIF/NC catalysts with superior electrocatalytic activities for the hydrogen evolution reaction. Ni-ZIF/NC exhibited comparable electrocatalytic performance to Pt/C in alkaline environments, showing potential for alternative new energy applications.