上海科技大学知识管理系统

Photocatalysis is a highly promising strategy for the direct conversion of inert methane (CH4). In this study, a ZnO semiconductor with a nanorod morphology (r-ZnO) was synthesized using a template-directed hydrothermal method, which was further used to prepare nAg/r-ZnO photocatalysts through impregnation and reduction. The structure, composition, and microstructure of nAg/r-ZnO were characterized using techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and UV-visible absorption spectroscopy (UV-vis). The in-depth mechanism of the photocatalytic conversion of CH(4 )was revealed through electron paramagnetic resonance (EPR) and radical capture experiments. The results showed that the introduction of Ag species promoted the separation of photoinduced electron (e(-)) and hole (h(+)) pairs, which facilitated the generation of reactive oxygen species (ROS). Therefore, the performance of photocatalytic CH4 oxidation can be significantly enhanced. Interestingly, formaldehyde (HCHO) was generated as the primary product instead of low-value methanol (CH3OH). Through optimization of Ag loading and reaction conditions, an excellent oxygenate (CH3OOH, CH3OH, and HCHO) yield of 15 551.60 mu mol g(-1) h(-1) with a high selectivity of 98.46% was achieved simultaneously, which has been rarely reported in previous studies.