Black phosphorus nanoflakes decorated hematite photoanode with functional phosphate bridges for enhanced water oxidation

Abstract Black phosphorus (BP) as a promising two-dimension semiconductor has been widely investigated for energy storage and conversion. Herein, a heterostructure photoanode by integrating BP nanoflakes and hematite was fabricated, in which the functional phosphate by the partially oxidation of BP could tightly bridge hematite and BP and improve the interfacial charge transfer. The well-matched band structures of BP and hematite, as well as the highly-efficient oxygen evolution reaction (OER) activity of BP can significantly facilitate the charge separation and transfer for enhanced water oxidation performance. As a result, the as-prepared heterostructure exhibits a high photocurrent density of 3.02 mA cm−2 at 1.23 V vs. RHE, much better than that of the sample without BP modification. Furthermore, a remarkable photocurrent density of 3.81 mA cm−2 at 1.23 V vs. RHE with good photostability can be achieved after the loading of FeNiOOH cocatalyst. This study clearly shows the excellent application of BP for solar water splitting.