A mild H3BO3 environment for water splitting

A weakly acidic H 3 BO 3 solution (pH = 5.1) was used to synthesize new oxygen-evolution catalysts for water splitting under mild conditions. Two novel oxygen-evolution catalysts, Co–BA i and Mn–BA i (BA i  = inorganic boric acid), were obtained in the H 3 BO 3 solution with added Co 2+ and Mn 2+ , respectively. The average oxygen evolution rate in the H 3 BO 3 solution with Co 2+ was 0.3133 μmol/h, about 70 times greater than the rate without a metal ion ; the rate with Mn 2+ was 1.13 μmol/h, about 250 times greater. The phases, morphologies, and compositions of the Co–BA i and Mn–BA i catalysts were analysed by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy .