Porous dehydroxyl cobalt phytate as electrocatalyst for high-efficiency water oxidation

Phytic acid (PA) is a six-fold dihydrogenphosphate ester of inositol with cost-effective, environmentally friendly, and safe properties. Here, we successfully synthesize the dehydroxyl cobalt phytate (PA-Co-400) using PA as phosphorus sources by a one-pot wet-chemistry strategy to prepare the precursor PA-Co and then heat treatment at 400 °C under an N2 atmosphere for dehydroxylation. The average diameter, specific surface area, surface element distribution, and catalytic activity of the catalyst are significantly affected by dehydroxylation temperature. The specific surface area increases first and then decreases with the treatment temperature from 200 °C to 600 °C. The SEM results indicate that the average diameter of PA-Co-400 particle is 68.90 nm. The as-prepared samples are used as an anode catalyst for electrocatalytic oxygen evolution reaction (OER). The PA-Co-400 exhibits splendid OER performances with an overpotential of 310.31 mV at j10 (η50 = 349.35 mV, η100 = 367.20 mV), which are even comparable to commercial RuO2 (η10 = 310.54 mV, η50 = 389.80 mV, η100 = 450.60 mV). Moreover, the PA-Co-400 has a small Tafel slope of 53.27 mV dec−1, which is lower than commercial RuO2 (81.71 mV dec−1). The ultra-long durability of PA-Co-400 was tested for over 80 h at current densities of 10 mA cm−2 without a significant reduction in 1 M KOH.