Black phosphorus as Promoter for Noble Metal-Free Photocatalytic Hydrogen Production

Photocatalysts which are stable to photocorrosion and noble metal-free, are highly desirable to achieve a light-driven hydrogen production which satisfies at the same time the criteria of low production cost and environmental sustainability. Herein, a new heterostructure TiO2/BP/CoP has been developed, where BP nanosheets by interacting strongly with TiO2 and CoP, can speed up the transfer of photogenerated electrons and thus increases the H2 production. Once BP is added to TiO2 (P25) as only 1% wt., the H2 evolution rate increases up to 3 times reaching a value of 830 ?mol/g?h under UV-Vis light irradiation. Integrating CoP nanoparticles as a cocatalyst up to 2% wt., the H2 production is furtherly promoted going to 7400 ?mol/g?h, 37 times higher than pristine TiO2. Photoluminescence and electrochemical impedance measurements showed that this heterostructure achieves a much more efficient charge separation and reduction of the internal resistance in comparison to pristine TiO2. Combining these data with UV-Vis Diffuse Reflectance and Mott-Schottky, a plausible mechanism was proposed.