Prussian blue analogues-derived bimetallic phosphide hollow nanocubes grown on Ni foam as water splitting electrocatalyst

The development of highly active and stable electrocatalysts for the water splitting using the earth-abundant transition metal as precursor is important for the renewable energy application. Prussian blue analogues (PBAs) are regarded as an ideal precursor for the preparation of electrocatalysts because of its abundant metal elements and various derived porous nanostructures. In this work, the (NiCo)2P hollow nanocubes, which are firmly grown on Ni foam, are prepared by PBAs and used as an water splitting electrocatalyst with high activity and stability in 1 M KOH solution. Benefiting from the synergistic effect of nickel and cobalt, hollow structure and high double-layer capacitance, the as-synthesized (NiCo)2P/NF catalyst shows an excellent electrocatalytic performance for the water splitting. To achieve current density of 10 mA cm−2, for HER and OER, this material requires overpotentials of 162 mV and 220 mV, respectively. As an integrated electrocatalyst for water splitting, the (NiCo)2P/NF needs a cell voltage of 1.62 V to achieve current density of 10 mA cm−2. Furthermore, this material has long-term electrocatalytic stability (over 30 h). The high catalytic activity of this material is attributed to the synergistic effect of component and the hollow structure of catalyst. This facile and novel method of preparing bimetallic phosphide electrocatalysts with hollow structure provides a broadened space for the design and synthesis of non-noble metal catalysts in the future.