Phase transformation of PiMoCo and their electrocatalytic activity for oxygen evolution reaction

Electrocatalysis caused by the crystallinity of catalysts is viewed as a key role of the electrocatalytic activity, but there are a few reports on it. Herein, we report the electrocatalytic activity depending on the crystallinity of Mo-doped Co₃(PO₄)₂(PiMoCo). A series of PiMoCo with different crystalline structures were controllably preparedviaco-precipitation and heat treatment. The PiMoCos obtained at room temperature and 800 °C were crystalline, while those obtained at 300-500 °C were amorphous. The electrocatalysis of PiMoCo depended on their phase transformation, which can be controlled by the temperature of heat treatment. The electrochemical performances for oxygen evolution reaction show that the PiMoCos with the amorphous phase exhibit high activity and stability. This work provides an insight into the electrocatalysis performance depending on the crystallinity of catalysts and the water molecules in the lattice of PiMoCo.