Structure and magnetic properties of an amine-templated one-dimensional cobalt-fluoro-sulfate containing CoF cubane and hydrogen evolution reaction (HER) performance of its derived carbon-wrapped CoSe nanorods.

Amine-templated 1D cobalt fluoro sulfate of the composition [(CH)NH][CoF(SO)(CNH)], consisting of CoF cubane-type secondary building unit, has been synthesized under solvothermal condition. The magnetic properties of the CoF cubane chain exhibited a low-temperature magnetic ordering below 17 K () attributed to intra-cluster ferromagnetic coupling and did not show spin-glass freezing. The selenylation of the CoF cubane chain leads to the formation of sphere-like CoSe in the hydrothermal route (CoSe@HT). At the same time, nanorods of CoSe encapsulated with carbon matrix were obtained in a sealed tube method (CoSe@ST). Moreover, CoSe@ST exhibited a higher hydrogen evolution reaction (HER) activity than CoSe@HT in an acidic medium with 177 mV overpotential to achieve the benchmark current density of 10 mA cm. The promising HER performance of derived CoSe@ST could be attributed to an increase in the geometrical and specific activity due to the encapsulation of N-doped carbon matrix over the CoSe nanorods that facilitate faster charge transfer at the electrode-electrolyte interface and higher electrochemical conductivity than the derived CoSe@HT. This work demonstrates a low-temperature, solvent- and reducing agent-free new synthetic approach for synthesizing framework-derived materials.