Photocatalytic reduction of CO\begin{document}$_2$\end{document} into various types of fuels has attracted great interest, and serves as a potential solution to addressing current global warming and energy challenges. In this work, Ag-Cu nanoparticles are densely supported on N-doped TiO\begin{document}$_2$\end{document} nanowire through a straightforward nanofabrication approach. The range of light absorption by N-doped TiO\begin{document}$_2$\end{document} can be tuned to match the plasmonic band of Ag nanoparticles, which allows synergizing a resonant energy transfer process with the Schottky junction. Meanwhile, Cu nanoparticles can provide active sites for the reduction of CO\begin{document}$_2$\end{document} molecules. Remarkably, the performance of photocatalytic CO\begin{document}$_2$\end{document} reduction is improved to produce CH\begin{document}$_4$\end{document} at a rate of 720 \begin{document}$\mu$\end{document}mol\begin{document}$\cdot$\end{document}g\begin{document}$^{-1}$\end{document}\begin{document}$\cdot$\end{document}h\begin{document}$^{-1}$\end{document} under full-spectrum irradiation. 相似文献
Accidental leakage of automobile oils is of great inclination to initiate pool fires in engine compartment, with threats to induce the flashover of other components and flame penetration into the passenger compartment. This paper presents experimental results of the ignition and burning behaviors of a kind of automobile oils (automatic transmission oil) using a cone calorimeter. Measurements of oil temperature, ignition time, mass loss and heat release rate are performed at different external heat fluxes and initial fuel depths. The comparison between experimental and numerical oil temperature evolutions shows that the variations of the ignition time at different experimental conditions depend on the heat dissipation process inside the liquid phase. The steady mass burning rate is nearly independent of initial fuel depth and has a linear relation with external heat fluxes. In addition, the results indicate an increase in peak heat release rate by a large margin initially, followed by a relatively small margin under thicker initial fuel depths, while its variations are proportional to external heat fluxes. Correlations are also developed to determine the peak heat release rate as a function of the initial fuel depth.
Developing efficient counter electrodes (CEs) and quantum dots made of earth-abundant and non-toxic elements is essential but still challenging for quantum dot-sensitized solar cells (QDSSCs). Here, we report a facile strategy to prepare self-supported and robust CoS2 and NiS nanocrystals-assembled nanosheets directly grown on carbon paper (MSx NS@CP) as efficient counter electrodes for QDSSCs. Such CEs integrate the merits of fast electron transfer from interconnected conductive scaffold, efficient mass transfer from hierarchically vertical nanosheet on 3D open substrate, as well as abundant highly active catalytic sites from metal sulphide nanocrystal units. As a result, QDDSCs based on such CoS2 NS@CP and NiS NS@CP CEs achieve a PCE of 8.88% and 7.53%, respectively. The detailed analyses suggest that CoS2 NS@CP has the highest catalytic activity and shows the lowest charger transfer resistance, leading to the highest PCE. These findings may inspire the design and exploration of other self-supported efficient CEs by integrating highly active catalysts onto 3D conductive networks for efficient QDSSCs. 相似文献
Heavy chemical doping and high electrical conductivity are two key factors for metal‐free graphene electrocatalysts to realize superior catalytic performance toward hydrogen evolution. However, heavy chemical doping usually leads to the reduction of electrical conductivity because the catalytically active dopants give rise to additional electron scattering and hence increased electrical resistance. A hierarchical nanoporous graphene, which is comprised of heavily chemical doped domains and a highly conductive pure graphene substrate, is reported. The hierarchical nanoporous graphene can host a remarkably high concentration of N and S dopants up to 9.0 at % without sacrificing the excellent electrical conductivity of graphene. The combination of heavy chemical doping and high conductivity results in high catalytic activity toward electrochemical hydrogen production. This study has an important implication in developing multi‐functional electrocatalysts by 3D nanoarchitecture design. 相似文献
A series of imidazolium chlorides for the formation of tridentate CNO‐donor palladium(II) complexes featuring N‐heterocyclic carbene moieties have been developed from cheap and readily available starting materials with high yields. Their palladium complexes were prepared by reactions between the ligand precursors and PdCl2 using K2CO3 as base in pyridine with reasonable yields. These air‐stable metal complexes were characterized using 1H NMR and 13C{1H} NMR spectroscopy and elemental analyses. Heteronuclear multiple bond correlation experiments were performed to identify key NMR signals of these compounds. The structures of two of the complexes were also established by single‐crystal X‐ray diffraction analysis. One of these complexes was successfully applied in the direct C―H functionalization reactions between heterocyclic compounds and aryl bromides, producing excellent yields of coupled products. The coupling reactions were scalable, allowing grams of coupled products to be obtained with a mere 2 mol% of Pd loading. The catalyst system developed allowed the large‐scale preparation of several push–pull chromophores straightforwardly. Photophysical properties based on UV–visible and fluorescence spectroscopy for these chromophores were investigated. Deep blue photoluminescence with moderate quantum efficiency and twisted intramolecular charge transfer excited state were observed for these chromophores. Density functional theory (DFT) and time‐dependent DFT calculations were performed to support the experimental results. 相似文献
Porous multipod Cu2O microcrystals were found to be an efficient, highly recyclable and eco‐friendly catalyst for the cross‐coupling reactions of aryl halides and terminal alkynes with high yields in aqueous media. Noteworthy, the Cu2O catalyst can be reused for several times without significant decrease in catalytic activity. 相似文献