氮化硼纳米片负载纳米Cu2O及其催化还原对硝基苯酚

Boron Nitride Nanosheets Supported Cu2O Nanoparticles: Synthesis and Catalytic Reduction for 4-nitrophenol

纳米级氧化亚铜具有高效的催化性能,但较差的稳定性使其应用受限。本研究采用简单可控的抗坏血酸液相还原及气氛焙烧法,制备了一种兼具高催化活性与催化稳定性的Cu2O/BNNSs-OH负载型催化剂,其中以聚乙烯吡咯烷酮(PVP)与水相变提供的"推-拉"作用剥离的氮化硼纳米片(BNNSs)为载体,液相还原反应体系pH=11时,抗坏血酸向Cu2+滴定制备的Cu2O纳米颗粒(2~7 nm)为活性组分。通过扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、原子力显微镜(AFM)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)、傅里叶变换红外光谱仪(FT-IR)及拉曼(Raman)光谱仪等对样品的形貌和结构进行表征,结果表明:Cu2O纳米粒子不但高度分散于载体表面, BNNSs对Cu2O还有一定的稳定作用,避免其被氧化成CuO。将Cu2O/BNNSs-OH应用于对硝基苯酚催化还原反应中,该催化剂表现出同贵金属类似的高催化活性, 5次重复利用后的转化率仍高达90%。

Despite excellent catalytic capability, Cu2O nanomaterial exhibits weak stability which limits its application. In this study, a novel kind of Cu2O, Cu2O/BNNSs-OH, supported catalyst with highly catalytic efficiency and stability, was facilely fabricated via a controllable liquid phase reduction of ascorbic acid and combining with an annealing process. Cu2O/BNNSs-OH catalyst was synthesized by using boron nitride nanosheets(BNNSs), prepared by the "push-pull" effect of polyvinylpyrrolidone(PVP) and water phase change, as a supporter and spherical Cu2O nanoparticles(2-7 nm) prepared by forward titration(ascorbic acid→Cu2+, solution with a pH 11) as active components. Morphology and structure of as-obtained samples were characterized by scanning electron microscopy(SEM), high resolution transmission electronic microscopy(HRTEM), atomic force microscopy(AFM), X-ray powder diffraction(XRD), X-ray photoelectron spectroscopy(XPS), Fourier transform infrared spectroscopy(FT-IR), and Raman spectroscopy. The results of the synthetic method showed that spherical Cu2O nanoparticles were uniformly dispersed on the carrier surface and BNNSs displayed some stabilization effect on Cu2O which could be prevented from being oxidized into CuO. Moreover, the catalytic activity was investigated by catalytic reduction reaction of 4-nitrophenol to 4-aminophenol. Cu2O/BNNSs-OH with high catalytic activity similar to the noble metal catalyst for the reduction of 4-nitrophenol is highly reusable for five successive cycles without significant degradation and activity loss.