Two-dimensional ultrathin networked CoP derived from Co(OH)₂ as efficient electrocatalyst for hydrogen evolution

The application of hydrogen is one of the promising ways to alleviate the global energy pollution. However, the electrocatalytic hydrogen evolution is currently limited by the low hydrogen evolution reaction (HER) kinetics based on noble metals. Thus, it is in urgent need to develop non-noble metal based electrocatalysts with an enhanced catalytic efficiency and environment-friendly properties. In the present study, two-dimensional ultrathin CoP networked materials are successfully synthesized by a low-temperature phosphorylation method with ultrathin mesh cobalt hydroxide precursor. Electrochemical test demonstrates that CoP electrocatalyst (CoPOH₁₂₀) needs only a small overpotential (12 mV) to achieve a current density as high as 10 mA cm⁻², which surpasses most of hydrogen evolution catalysts working in alkaline environment. Most significantly, the overpotential of CoPOH₁₂₀ electrode only drops to 38 mV after 1000 cycles of cyclic voltammetry (CV), exhibiting marvelous cyclic stability. Our ultrathin two-dimensional networked CoP materials promise the applications for various electrochemical energy conversion and storage fields. Graphical abstract: Two-dimensional ultrathin CoP network materials as HER catalyst exhibits outstanding performance with extremely low overpotential and superior stability. [Figure not available: see fulltext.]