pH‐Dependent Degradation of Layered Black Phosphorus: Essential Role of Hydroxide Ions

Abstract

Abstract The practical application of layered black phosphorus (LBP) is compromised by fast decomposition in the presence of H 2 O and/or O 2 . The role of H 2 O is controversial. Herein, we propose a hydroxide ion (OH − )‐initiated degradation mechanism for LBP to elucidate the role of H 2 O. We found that LBP degraded faster in alkaline solutions than in neutral or acidic solutions with or without O 2 . Degradation rates of LBP increased linearly from pH 4 to 10. Density functional theory (DFT) calculations showed that OH − initiated the decomposition of LBP through breaking the P−P bond and forming a P−O bond. The detection of hypophosphite, generated from OH − reacting with P atoms, confirmed the hypothesis. Protons acted in a way distinctive from OH − , by inducing deposition/aggregation or forming a cation–π layer to protect LBP from degradation. This work reveals the degradation mechanism of LBP and thus facilitates the development of effective stabilization technologies.