Construction of Co2P/CoP@Co@NCNT rich-interface to synergistically promote overall water splitting

Constructing hetemstructures with rich-interface by the interfacial electron modulating is the key to integrating the rich functionalities for elcetmcatalysis. Herein, heterogeneous structural Co2P/CoP hollow nanospheres embedded in N-doped carbon nanotubes (Co2P/CoP@Co@NCNT) to form a rich-interface catalyst is fabricated by a controlled phosphatization. Experimental results manifest that the metallic cobalt embedded in N-doping carbon nanotubes by one-step thermal decomposition can be used as anchoring sites for heterojunction and carbon carrier, thus providing abundant active sites, accelerating the electrical conductivity. Besides, the selfassembled Co2P/CoP hollow nanospheres was embedded on the surface of Co@NCNT, which is conducive to the formation of more interfaces, and adjusting the surface electronic structure. Benefiting from the synergies between Co2P, CoP and Co@NCNT, the as-synthesized Co2P/CoP@Co@NCNT exhibits enhanced active sites and increased intrinsic activity, resulting in a better bifunctional performance in 1.0 M KOH, only requiring over-potentials of 118 and 256 mV to deliver a current density at 10 mA cm(-2) for HER and OER, respectively. As cathodes, it also delivers low rpm values of 136 mV in 0.5 M H2SO4. Moreover, a two-electrode electrolyzer assembled by Co2P/CoP@Co@NCNT presents a cell voltage of 1.6 V at 10 mA cm(-2) with impressive long-life cycling stability, showing great potential for economical and scalable water splitting application.

Automated summary

By controlling the phosphatization process, Co2P/CoP hollow nanospheres embedded in N-doped carbon nanotubes were fabricated to form a rich-interface catalyst, providing abundant active sites and enhanced electrical conductivity. The synthesized Co2P/CoP@Co@NCNT catalyst exhibited outstanding bifunctional performance in 1.0 M KOH, low over-potentials in 0.5 M H2SO4, and impressive long-life stability in a two-electrode electrolyzer setup, showing great potential for water splitting applications.