Simultaneous Preparation and Functionalization of Ultrathin Few−layer Black Phosphorus Nanosheets and Their Electrocatalytic OER and HER Performance

Abstract A convenient liquid phase exfoliation method is reported here to prepare functionalized few−layer black phosphorus (BP) nanosheets by using succinic acid (SA) or L−ascorbic acid (L−AA) −assisted tip−ultrasonicated exfoliation. The thickness of the obtained nanosheets is about 2–2.5 nm, which is equivalent to 4–5 layers of BP atoms. And SA−BP−1 : 3 exhibits a best OER and HER performance in the group of SA−BP with different weight ratios, requiring an overpotential of 369.8 mV for OER and 235 mV for HER to achieve the current density of 10 mA cm −2 , respectively. Meantime, L−AA−BP‐1 : 1 presents a great OER and HER performance in the group of L−AA−BP with different weight ratios, requiring an overpotential of 459.5 mV for OER and 224 mV for HER to achieve the current density of 10 mAcm −2 , respectively. And two groups of the samples significantly enhance the OER and HER performance of few−layer BP nanosheets (550 mV and 431 mV). In addition, both the consecutive cyclic voltammetry and chronoamperometric measurements reveal the outstanding electrocatalytic stability of the samples.