Low-temperature synthesis of hierarchical amorphous basic nickel carbonate particles for water oxidation catalysis

Amorphous nickel carbonate particles are catalysts for the oxygen evolution reaction (OER), which plays a critical role in the electrochemical splitting of water. The amorphous nickel carbonate particles can be prepared at a temperature as low as 60 °C by an evaporation-induced precipitation (EIP) method. The products feature hierarchical pore structures. The mass-normalized activity of the catalysts, measured at an overpotential of 0.35 V, was 55.1 Ag^-1, with a Tafel slope of only 60 mVdec^-1. This catalytic activity is superior to the performance of crystalline NiO_x particles and β-Ni(OH)₂ particles, and compares favorably to state-of-the-art RuO₂ catalysts. The activity of the amorphous nickel carbonate is remarkably stable during a 10000 s chronoamperometry test. Further optimization of synthesis parameters reveals that the amorphous structure can be tuned by adjusting the H₂O/Ni ratio in the precursor mixture. These results suggest the potential application of easily prepared hierarchical basic nickel carbonate particles as cheap and robust OER catalysts with high activity.