Ni-nanoparticle-bound boron nitride nanosheets prepared by a radiation-induced reduction-exfoliation method and their catalytic performance

Abstract

The efficient exfoliation of hexagonal boron nitride (h-BN) to fabricate boron nitride nanosheets (BNNS) is a challenging task in the popular field of two-dimensional material preparation. In this paper, a new radiation-induced reduction-exfoliation method is introduced to achieve the one-step exfoliation of h-BN to form Ni-nanoparticle-(NiNP)-bound BNNS (Ni/BNNS) in a binary isopropanol/water medium using gamma-ray radiation at ambient temperature and pressure. The process involves the effective intercalation of Ni²⁺ ions into h-BN interlayers dispersed in the isopropanol/water medium, followed by the in situ growth of NiNPs under gamma-ray irradiation. Taking advantage of the volume expansion effect generated by the growth of the NiNPs and with help from a cationic surfactant, such as hexadecyltrimethylammonium chloride (CTAC), sheet-like Ni/BNNS in 200 nm squares and with an average BNNS thickness of less than 5 nm can be peeled from h-BN and stably dispersed in water. The prepared magnetic Ni/BNNS exhibits good catalytic performance, excellent structural stability, and reusability toward the reduction of 2-nitroaniline (2-NA). After 5 cycles, the conversion of 2-NA still reaches 95.9% within 500 s. More interestingly, when Ni/BNNS was dispersed in water/methanol solution at a content of 0.17 mg mL⁻¹ followed by exposure to simulated sunlight irradiation, H₂ evolution of 8404.3 μmol g_Ni⁻¹ within 2 h can be detected. This work not only provides a new idea for realizing the exfoliation of layers of nanoscale sheets from h-BN, but it also opens a new route to the one-step preparation of two-dimensional-material-supported nanometal catalysts by taking advantage of gamma-ray radiation.