A mild H3BO3 environment for water splitting

A weakly acidic H3BO3 solution (pH = 5.1) was used to synthesize new oxygen-evolution catalysts for water splitting under mild conditions. Two novel oxygen-evolution catalysts, Co–BAi and Mn–BAi (BAi = inorganic boric acid), were obtained in the H3BO3 solution with added Co2+ and Mn2+, respectively. The average oxygen evolution rate in the H3BO3 solution with Co2+ was 0.3133 μmol/h, about 70 times greater than the rate without a metal ion; the rate with Mn2+ was 1.13 μmol/h, about 250 times greater. The phases, morphologies, and compositions of the Co–BAi and Mn–BAi catalysts were analysed by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy.