•High quality CoP nanotubes have been successfully synthesized.•The nanotubes formed via the nano-scale Kirkendall effects.•The CoP nanotubes shown enhanced hydrogen evolution reaction activity.CoP nanotubes are synthesized through a nanoscale Kirkendall effect using Co(CO3)0.35Cl0.2(OH)1.10 nanorods as the cobalt source and template. CoP nanotubes and nanorods can be selectively synthesized by controlling the Co and P molar ratio in the phosphidation process, further confirming the diffusion controlled Kirkendall effect. Benefiting from the high surface area and improved mass and charge transportation, the CoP nanotubes exhibit higher hydrogen evolution catalytic activity than that of CoP nanorods and nanoparticles. The CoP nanotubes have a small onset potential of 55 mV for hydrogen evolution reaction, and high durability indicating by that the catalytic activity almost no change after 2000 cyclic voltammetry cycles.Download high-res image (73KB)Download full-size image

One-dimensional Ag–Ni core–shell nanowires were successfully synthesized by a simple two-step method, in which Ni shells grow epitaxially at the surface of silver nanowires (Ag NWs) to form a unique core–shell structure. The thickness of Ni shells can be finely controlled from 50 to 150 nm by adjusting the initial Ni to Ag atomic ratios. The electrocatalytic performance of the Ag–Ni core–shell NWs can be adjusted by tuning their compositions, and the optimized Ag to Ni atomic ratio is 1 : 1. The Ag–Ni core–shell nanowires exhibit superior electrocatalytic activity to pure Ni nanoparticles and Ag NWs, showing a strong synergistic effect toward alkaline hydrogen evolution reaction (HER). A morphological effect was demonstrated by comparing with Ag–Ni core–shell nanoparticles. The enhanced HER activity of Ag–Ni core–shell NWs can be attributed to the synergetic effect between Ag and Ni, the larger number of surface active sites and the fast charge transport. This approach provides a reasonable attempt for designing and developing 1D electrocatalysts based on Ag nanowires.

Two different kinds of γ-Al2O3 precursors: stick-like ammonium aluminum carbonate hydroxide and willow leaf-like boehmite could be selectively synthesized via a facile hydrothermal method by just adjusting reaction temperature. After heat treatment, γ-Al2O3 with two different morphologies (stick-like and willow leaf-like) were synthesized and used as supports for CoMo hydrodesulfurization catalysts. Fourier transform infrared spectroscopy of pyridine adsorption and NH3-temperature-programmed desorption showed that stick-like γ-Al2O3 (ACH) and willow leaf-like γ-Al2O3 (AOH) exhibited a lower Lewis acidity than commercial γ-Al2O3. X-ray diffraction indicated that CoMo oxidic catalysts supported on ACH and AOH contained more β-CoMoO4 phase. X-ray photoelectron spectroscopy and high resolution transmission electron microscopy revealed that after presulfurization, more CoMoS active sites and multilayered (Co)MoS2 slabs formed on ACH and AOH supports, thereby creating catalysts with a higher hydrodesulfurization activity in the hydrodesulfurization of thiophene and 4,6-dimethyldibenzothiophene.

Herein, we achieved successful synthesis of uniform Ir–Cu nanoframes with highly open structures by a facile one-pot strategy. The key to obtain alloy nanoframes was the careful control over the reduction and galvanic replacement reactions between different metals. The as-prepared Ir–Cu was proved to be an effective template for constructing trimetallic nanoframes. Furthermore, these highly open nanostructures exhibited excellent electrocatalytic performance toward oxygen evolution reaction in alkaline media.

MoS2 catalysts with more active sites and larger surface areas were successfully synthesized via a simple hydrothermal reaction method, and the surface structure of MoS2 was readily tailored by simply adding thiophene during the synthesis procedure. The MoS2 samples synthesized with thiophene, especially MoS2 prepared with 200 μL of thiophene, concomitantly exhibited better activity for both hydrodesulfurization and hydrogen evolution reactions. The present work provides an efficient route to achieve highly efficient MoS2 catalysts, and may open up a new avenue for the morphological design of layered structural compounds like MoS2.

A significant morphology change from ceria nanoparticles to nanocubes was observed in ceria nanocrystals when CO molecules were introduced into the synthetic system, which is attributed to the surface selective growth driven by strong surface selective adsorption of CO onto the ceria surface.

In this work, a general colloid synthesis method for CeO2–Al2O3, CeO2–SiO2, and CeO2–TiO2 core-shell spheres was reported. The properties of these CeO2-based composites were greatly dependent on the additive species. A diffusion-controlled kinetic model was applied to explore the morphology and crystallinity evolution of these core-shell spheres. CeO2–Al2O3 spheres undergo a significant morphology evolution when the Ce/Al molar ratio is varied from 1:0.2 to 1:1. It also provided an effective way to observe the diffusion channel for mass transport in the diffusion process by dissolving the Al2O3 in CeO2–Al2O3 spheres in alkaline solution. Moreover, a significant composition and structure dependent nature was observed from the UV-vis absorption spectra of these CeO2–Al2O3, CeO2–SiO2, and CeO2–TiO2 core-shell spheres.

Hierarchiral NiO flower-like microspheres with tunable porosity were prepared based on a facile solvothermal method. Three kinds of NiO micro-flowers (NiO-A, NiO-B, and NiO-C) with different porosity have been fabricated mainly by tuning the concentration of nickel nitrate. These flower-like microspheres are comprised of densely packed irregular sheets and display a multi-peaks pore distribution in a wide range in both mesoporous and macroporous regions. The BET surface area of NiO-A, NiO-B and NiO-C is 59.9 m2 g−1, 50.2 m2 g−1 and 15.1 m2 g−1, respectively. The pore volume of NiO-A, NiO-B and NiO-C is 0.2214 cm3 g−1, 0.0829 cm3 g−1 and 0.0549 cm3 g−1, respectively. These NiO spheres show a strong morphology dependant nature for CO oxidation catalysis. Compared to the conventional NiO nanoparticles, these flower-like NiO micro-spheres possess a superior catalytic activity for CO oxidation.

Nearly monodisperse LaAlO3 hollow spheres are synthesized by a novel precursor thermal decomposition method. Spherical colloids of capsulelike precursors with uniform diameters of 273 ± 35 nm have been synthesized by a solvothermal method. These spherical colloids could convert to LaAlO3 hollow spheres with diameters of 166 ± 26 nm by a thermal decomposition process. The thermal transformation process from the precursors to LaAlO3 was characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), and the Fourier transform infrared spectroscopy (FT-IR). By the doping of various lanthanide ions (Sm3+, Eu3+, and Tb3+), the emission luminescence of lanthanide-doped LaAlO3 hollow microspheres can be tuned from red to green. In particular, these luminescent LaAlO3 hollow spheres can be well dispersed in polar solvents such as the ethanol and water, which broadens the range of potential applications of these hollow spheres. The UV–vis absorption spectra show energy absorption at 211, 223, and 313 nm corresponding to the host lattice absorption and charge-transfer transitions. The results are in good agreement with the peaks observed in the excitation spectra.

Hierarchiral NiO flower-like microspheres with tunable porosity were prepared based on a facile solvothermal method. Three kinds of NiO micro-flowers (NiO-A, NiO-B, and NiO-C) with different porosity have been fabricated mainly by tuning the concentration of nickel nitrate. These flower-like microspheres are comprised of densely packed irregular sheets and display a multi-peaks pore distribution in a wide range in both mesoporous and macroporous regions. The BET surface area of NiO-A, NiO-B and NiO-C is 59.9 m2 g−1, 50.2 m2 g−1 and 15.1 m2 g−1, respectively. The pore volume of NiO-A, NiO-B and NiO-C is 0.2214 cm3 g−1, 0.0829 cm3 g−1 and 0.0549 cm3 g−1, respectively. These NiO spheres show a strong morphology dependant nature for CO oxidation catalysis. Compared to the conventional NiO nanoparticles, these flower-like NiO micro-spheres possess a superior catalytic activity for CO oxidation.

A significant morphology change from ceria nanoparticles to nanocubes was observed in ceria nanocrystals when CO molecules were introduced into the synthetic system, which is attributed to the surface selective growth driven by strong surface selective adsorption of CO onto the ceria surface.

Two different kinds of γ-Al2O3 precursors: stick-like ammonium aluminum carbonate hydroxide and willow leaf-like boehmite could be selectively synthesized via a facile hydrothermal method by just adjusting reaction temperature. After heat treatment, γ-Al2O3 with two different morphologies (stick-like and willow leaf-like) were synthesized and used as supports for CoMo hydrodesulfurization catalysts. Fourier transform infrared spectroscopy of pyridine adsorption and NH3-temperature-programmed desorption showed that stick-like γ-Al2O3 (ACH) and willow leaf-like γ-Al2O3 (AOH) exhibited a lower Lewis acidity than commercial γ-Al2O3. X-ray diffraction indicated that CoMo oxidic catalysts supported on ACH and AOH contained more β-CoMoO4 phase. X-ray photoelectron spectroscopy and high resolution transmission electron microscopy revealed that after presulfurization, more CoMoS active sites and multilayered (Co)MoS2 slabs formed on ACH and AOH supports, thereby creating catalysts with a higher hydrodesulfurization activity in the hydrodesulfurization of thiophene and 4,6-dimethyldibenzothiophene.

Herein, we achieved successful synthesis of uniform Ir–Cu nanoframes with highly open structures by a facile one-pot strategy. The key to obtain alloy nanoframes was the careful control over the reduction and galvanic replacement reactions between different metals. The as-prepared Ir–Cu was proved to be an effective template for constructing trimetallic nanoframes. Furthermore, these highly open nanostructures exhibited excellent electrocatalytic performance toward oxygen evolution reaction in alkaline media.