Tremendous efforts have been devoted to explore energy-efficient strategies of ammonia synthesis to replace Haber–Bosch process which accounts for 1.4% of the annual energy consumption. In this study,atomically dispe...Tremendous efforts have been devoted to explore energy-efficient strategies of ammonia synthesis to replace Haber–Bosch process which accounts for 1.4% of the annual energy consumption. In this study,atomically dispersed Au_1 catalyst is synthesized and applied in electrochemical synthesis of ammonia under ambient conditions. A high NH_4^+ Faradaic efficiency of 11.1% achieved by our Au_1 catalyst surpasses most of reported catalysts under comparable conditions. Benefiting from efficient atom utilization, an NH_4^+ yield rate of 1,305 lg h^(-1) mg_(Au)^(-1) has been reached, which is roughly 22.5 times as high as that by supported Au nanoparticles. We also demonstrate that by employing our Au_1 catalyst, NH4+can be electrochemically produced directly from N_2 and H_2 with an energy utilization rate of 4.02 mmol kJ^(-1). Our study provides a possibility of replacing the Haber–Bosch process with environmentally benign and energy-efficient electrochemical strategies.展开更多
Bismuth tungstate(Bi2 WO6) has many intriguing properties and has been the focus of studies in a variety of fields, especially photocatalysis. However, its application in gas-sensing has been seldom reported.Here, we ...Bismuth tungstate(Bi2 WO6) has many intriguing properties and has been the focus of studies in a variety of fields, especially photocatalysis. However, its application in gas-sensing has been seldom reported.Here, we successfully synthesized assembled hierarchical Bi2 WO6 which consists of ultrathin nanosheets with crystalline-amorphous composite phase by a one-step hydrothermal method. X-ray diffraction(XRD), X-ray photoemission spectroscopy(XPS), field-emission scanning electron microscopy(FESEM),and high-resolution transmission electron microscopy(HRTEM) techniques were employed to characterize its composition, morphology, and microstructure. By taking advantage of its unique microstructure,phase composition, and large surface area, we show that the resulting Bi2 WO6 is capable of detecting ethanol gas with quick response(7 s) and recovery dynamic(14 s), extremely high sensitivity(Ra/Rg= 60.8@50 ppm ethanol) and selectivity. Additionally, it has excellent reproducibility and long-term stability(more than 50 d). The Bi2 WO6 outperform the existing Bi2 WO6-based and most of the other state-of-the-art sensing platforms. We not only provided one new member to the field of gas sensor,but also offered several strategies to reconstruct nanomaterials.展开更多
基金supported by the National Key R&D Program of China (2017YFA0208300)the National Natural Science Foundation of China (21522107, 21671180, 21521091, 21390393, U1463202, and 21522305)
文摘Tremendous efforts have been devoted to explore energy-efficient strategies of ammonia synthesis to replace Haber–Bosch process which accounts for 1.4% of the annual energy consumption. In this study,atomically dispersed Au_1 catalyst is synthesized and applied in electrochemical synthesis of ammonia under ambient conditions. A high NH_4^+ Faradaic efficiency of 11.1% achieved by our Au_1 catalyst surpasses most of reported catalysts under comparable conditions. Benefiting from efficient atom utilization, an NH_4^+ yield rate of 1,305 lg h^(-1) mg_(Au)^(-1) has been reached, which is roughly 22.5 times as high as that by supported Au nanoparticles. We also demonstrate that by employing our Au_1 catalyst, NH4+can be electrochemically produced directly from N_2 and H_2 with an energy utilization rate of 4.02 mmol kJ^(-1). Our study provides a possibility of replacing the Haber–Bosch process with environmentally benign and energy-efficient electrochemical strategies.
基金supported by the National Key R&D Program of China (2017YFA0208300 and 2017YFA0700104)the National Natural Science Foundation of China (61671284, U1704255, and 21671180)the support of the Shanghai Municipal Education Commission (Peak Discipline Construction Program)
文摘Bismuth tungstate(Bi2 WO6) has many intriguing properties and has been the focus of studies in a variety of fields, especially photocatalysis. However, its application in gas-sensing has been seldom reported.Here, we successfully synthesized assembled hierarchical Bi2 WO6 which consists of ultrathin nanosheets with crystalline-amorphous composite phase by a one-step hydrothermal method. X-ray diffraction(XRD), X-ray photoemission spectroscopy(XPS), field-emission scanning electron microscopy(FESEM),and high-resolution transmission electron microscopy(HRTEM) techniques were employed to characterize its composition, morphology, and microstructure. By taking advantage of its unique microstructure,phase composition, and large surface area, we show that the resulting Bi2 WO6 is capable of detecting ethanol gas with quick response(7 s) and recovery dynamic(14 s), extremely high sensitivity(Ra/Rg= 60.8@50 ppm ethanol) and selectivity. Additionally, it has excellent reproducibility and long-term stability(more than 50 d). The Bi2 WO6 outperform the existing Bi2 WO6-based and most of the other state-of-the-art sensing platforms. We not only provided one new member to the field of gas sensor,but also offered several strategies to reconstruct nanomaterials.
