Tao Chen,Manli Wang,Donghang Hu,Qianlin Ju,Kaige Zhao,Liang Fu,Zelin Chen,Xiaolong Yu,Changjiu Li
The mainstream electrocatalysts for direct ethanol fuel cells (DEFCs) are Pt- or Pd-based nanomaterials, which are severely hampered by CO intermediate poisoning and the relatively low selectivity of the C1 pathway in anodic ethanol oxidation reaction (EOR), thereby impeding the efficiency enhancement and practical application of DEFCs. Herein, we report a Pt-decorated amorphous PdS nanowire [denoted as a-Pd(S)NWs/Pt] catalyst with abundant crystalline/amorphous heterogeneous interfacial active sites for alkaline EOR. The a-Pd(S)NWs/Pt was demonstrated a superior EOR mass activity of 6.16 A·mgPd+Pt–1, which is 22.81 times over that of commercial Pt/C (0.27 A·mgPt–1) and 34.22 times over that of commercial Pd/C (0.18 A·mgPd–1). Additionally, the a-Pd(S)NWs/Pt exhibited considerable stability, significantly enhanced resistance to CO poisoning and enhanced selectivity for the EOR C1 pathway. Density functional theory calculations and experimental results further revealed that the optimized COads and OHads binding energies due to the decoration of Pt nanoclusters can be responsible for the enhanced CO resistance and C1 selectivity of a-Pd(S)NWs/Pt. Furthermore, benefiting from its optimized electronic configuration at the interfacial active sites and the appropriate intermediate adsorption capacity, the a-Pd(S)NWs/Pt electrocatalyst was successfully extended to the electrocatalytic methanol and ethylene glycol oxidation reaction systems.
Lei Ma,Shiyan Yuan,Taotao Jiang,Xiangming Zhu,Chunshan Lu,Xiaonian Li
Sulfur species (e.g., H2S or SO2) are the natural enemies of most metal catalysts, especially palladium catalysts. The previously reported methods of improving sulfur-tolerance were to effectively defer the deactivation of palladium catalysts, but could not prevent PdO and carrier interaction between sulfur species. In this report, novel sulfur-tolerant SiO2supported Pd4S catalysts (5 wt. % Pd loading) were prepared by H2S–H2aqueous bubble method and applied to catalytic complete oxidation of methane. The catalysts were characterization by X-ray diffraction, Transmission electron microscopy, X-ray photoelectron Spectroscopy, temperature-programmed oxidation, and temperature-programmed desorption techniques under identical conditions. The structural characterization revealed that Pd4S and metallic Pd0were found on the surface of freshly prepared catalysts. However, Pd4S remained stable while most of metallic Pd0was converted to PdO during the oxidation reaction. When coexisting with PdO, Pd4S not only protected PdO from sulfur poisoning, but also determined the catalytic activity. Moreover, the content of Pd4S could be adjusted by changing H2S concentration of H2S–H2mixture. When H2S concentration was 7 %, the Pd4S/SiO2catalyst was effective in converting 96% of methane at the 400 °C and also exhibited long-term stability in the presence of 200 ppm H2S. A Pd4S/SiO2catalyst that possesses excellent sulfur-tolerance, oxidation stability, and catalytic activity has been developed for catalytic complete oxidation of methane.
Yang Rong,Liang Tang,Yahui Song,Shengnan Wei,Zhaohong Zhang,Jun Wang
A new visible-light-sensitive photocatalyst, Er3+:Y3Al5O12/MoS2–NaTaO3–PdS, was prepared by hydrothermal, liquid boiling and deposition methods. The prepared photocatalysts were all characterized using an X-ray diffractometer (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM). The photocatalytic activity of the prepared photocatalysts was evaluated via photocatalytic degradation of amaranth as a refractory pollutant with simultaneous hydrogen evolution under visible-light irradiation. Moreover, the effects of the visible-light irradiation time and molar ratio of Er3+:Y3Al5O12 and NaTaO3 on the photocatalytic capability of Er3+:Y3Al5O12/MoS2–NaTaO3–PdS were studied. The results show that the use of Er3+:Y3Al5O12 can improve the utilization ratio of visible light (solar light) for NaTaO3. The optimum ratio of Er3+:Y3Al5O12 and NaTaO3 is 0.45 : 1.00. In addition, a study of extended reusability shows that the prepared photocatalyst can be effectively recycled for three repetitive cycles without an apparent deactivation of the photocatalytic activity. A visible-light photocatalytic degradation mechanism of amaranth with simultaneous hydrogen evolution is also proposed.
危险品化学品经营许可证（带存储）