ATMP derived cobalt-metaphosphate complex as highly active catalyst for oxygen reduction reaction

Rational design and facile synthesis of highly active electrocatalysts with low cost for oxygen reduction reaction (ORR) are always of great challenge. Specifically, development of a new type of energy-saving materials with convenient method is regarded as the current bottleneck. Herein, an innovative strategy based on amino trimethylene phosphonic acid (ATMP) as chelating agent for cobalt-metaphosphate coordination polymer is reported to one-pot synthesis of a novel precursor in methanol for ORR electrocatalyst. Carbonization of the precursor at 900 °C at N₂ atmosphere results in the feasible formation of cobalt metaphosphate based composite (Co(PO₃)₂/NC). A further step in the thermal cleavage at 650 °C at air for 4 h, Co(PO₃)₂/NC can be finally transformed into inorganic Co(PO₃)₂. Advanced spectroscopic techniques and density function theory (DFT) calculations are applied to confirm the main catalytically active center and the physical properties of Co(PO₃)₂/NC. This obtained Co(PO₃)₂/NC nanocomposite exhibits superior electrocatalysis to Co(PO₃)₂ with an enhanced onset potential (0.906 V vs. RHE) and diffusion limiting current (5.062 mA cm⁻²), which are roughly close to those of commercial 20% Pt/C (0.916 V, 5.200 mA cm⁻²).