Implanted cobalt ions in two zinc-based frameworks: Improved electrocatalyst for hydrogen evolution reaction

Hydrogen energy has been considering as an ideal renewable energy source and playing a very important role in daily life. Noble metal catalysts have shown excellent catalytic performance in electrolysis of water for hydrogen evolution, but their scarcity and high cost limit their large-scale use. Therefore, the design of non-noble metal catalysts with high catalytic activity and stability and low cost is an urgent problem to be solved. Two zinc-based coordination polymers have been synthesized by one-pot method. We developed an effective method through simple Co2+ doping, which improved and optimized the electrocatalytic performance to obtain two high-quality electrocatalysts for electrolysis of water to produce hydrogen with low starting potential (−210 mV and −240 mV), high Tafel efficiency (117.7 mV dec-1 and 127.8 mV dec-1) and excellent cycle stability (>95% LSV retention after at least 2000 cycles). We also synthesized two isomorphic Co-based or Ni-based coordination polymers, and found that their electrocatalytic performances were improved to some extent after the introduction of Co ions, but the effects were not as good as that of zinc-based coordination polymers. This work not only provides two examples of good electrocatalyst, but also provides an idea to improve and optimize the electrocatalytic performance.