Black phosphorus synthesized by solvothermal reaction from red phosphorus and its catalytic activity for water splitting

We have succeeded in synthesizing black phosphorus (BP) by a one-pot solvothermal reaction of red phosphorus (RP) and ethylenediamine (ED) used as a solvent. To examine the reaction mechanism, we have investigated the influence of the synthesis conditions on BP, and the valence of dissolved phosphorus in the solvent after the reaction. P 0 species and P 3+ like species are very likely dissolved in ED as intermediates for BP production. Optimizing the reaction conditions, i.e. , temperature, the charging amount of RP in ED and the particle size of RP, BP was synthesized with high yield. The synthesized BP has an extra peak at 10.2° in the X-ray diffraction pattern, which was assigned to stacking faults or periodic distortion in the direction of the c axis by simulation of diffraction. The synthesized BP with a Co-P cocatalyst showed high photocatalytic activity for hydrogen evolution from methanol aqueous solution under visible light irradiation. We have succeeded in synthesizing black phosphorus employing a one-pot solvothermal reaction of red phosphorous and ethylenediamine used as a solvent.