14 research outputs found
Highly efficient catalytic production of oximes from ketones using in situ-generated H<sub>2</sub>O<sub>2</sub>
The ammoximation of cyclohexanone using preformed hydrogen peroxide (H2O2) is currently applied commercially to produce cyclohexanone oxime, an important feedstock in nylon-6 production. We demonstrate that by using supported gold-palladium (AuPd) alloyed nanoparticles in conjunction with a titanium silicate-1 (TS-1) catalyst, H2O2 can be generated in situ as needed, producing cyclohexanone oxime with >95% selectivity, comparable to the current industrial route. The ammoximation of several additional simple ketones is also demonstrated. Our approach eliminates the need to transport and store highly concentrated, stabilized H2O2, potentially achieving substantial environmental and economic savings. This approach could form the basis of an alternative route to numerous chemical transformations that are currently dependent on a combination of preformed H2O2 and TS-1, while allowing for considerable process intensification
Room temperature all-solid-state lithium batteries based on a soluble organic cage ionic conductor
All solid-state lithium batteries (SSLBs) are poised to have higher energy density and better safety than current liquid-based Li-ion batteries, but a central requirement is effective ionic conduction pathways throughout the entire cell. Here we develop a catholyte based on an emerging class of porous materials, porous organic cages (POCs). A key feature of these Li(+) conducting POCs is their solution-processibility. They can be dissolved in a cathode slurry, which allows the fabrication of solid-state cathodes using the conventional slurry coating method. These Li(+) conducting cages recrystallize and grow on the surface of the cathode particles during the coating process and are therefore dispersed uniformly in the slurry-coated cathodes to form a highly effective ion-conducting network. This catholyte is shown to be compatible with cathode active materials such as LiFePO(4), LiCoO(2) and LiNi(0.5)Co(0.2)Mn(0.3)O(2), and results in SSLBs with decent electrochemical performance at room temperature
Enhanced selective oxidation of benzyl alcohol via in situ H2O2 production over supported Pd-based catalysts
Bimetallic Pd-Fe catalysts supported on TiO2 are shown to be highly effective toward the selective oxidation of benzyl alcohol to benzaldehyde via the in situ production of H2O2 from molecular H2 and O2, under conditions where no reaction is observed with molecular O2 alone. The rate of benzyl alcohol oxidation observed over supported Pd-Fe nanoparticles is significantly higher than those of either Pd-Au or Pd-only analogues. This enhanced activity can be attributed to the bifunctionality of the Pd-Fe catalyst to both synthesize H2O2 and catalyze the production of oxygen-based radical specie,s as indicated by an electron paramagnetic resonance analysis. Further studies also reveal the noninnocent nature of the solvent, resulting in the propagation of radical generation pathways
PtFeCoNiCu high-entropy solid solution alloy as highly efficient electrocatalyst for the oxygen reduction reaction
Summary: Searching for an efficient, durable, and low cost catalyst toward oxygen reduction reaction (ORR) is of paramount importance for the application of fuel cell technology. Herein, PtFeCoNiCu high-entropy alloy nanoparticles (PFCNC-HEA) is reported as electrocatalyst toward ORR. It shows remarkable ORR catalytic mass activity of 1.738 A mg−1Pt at 0.90 V, which is 15.8 times higher than that of the state-of-art commercial Pt/C catalyst. It also exhibits outstanding stability with negligible voltage decay (3 mV) after 10k cycles accelerated durability test. High ORR activity is ascribed to the ligand effect caused by polymetallic elements, the optimization of the surface electronic structure, and the formation of multiple active sites on the surface. In the proton exchange membrane fuel cell setup, this cell delivers a power density of up to 1.380 W cm−2 with a cathodic Pt loading of 0.03 mgPt cm−2, demonstrating a promising catalyst design direction for highly efficient ORR
Highly efficient catalytic production of oximes from ketones using in situ-generated H<sub>2</sub>O<sub>2</sub>
The ammoximation of cyclohexanone using preformed hydrogen peroxide (H2O2) is currently applied commercially to produce cyclohexanone oxime, an important feedstock in nylon-6 production. We demonstrate that by using supported gold-palladium (AuPd) alloyed nanoparticles in conjunction with a titanium silicate-1 (TS-1) catalyst, H2O2 can be generated in situ as needed, producing cyclohexanone oxime with >95% selectivity, comparable to the current industrial route. The ammoximation of several additional simple ketones is also demonstrated. Our approach eliminates the need to transport and store highly concentrated, stabilized H2O2, potentially achieving substantial environmental and economic savings. This approach could form the basis of an alternative route to numerous chemical transformations that are currently dependent on a combination of preformed H2O2 and TS-1, while allowing for considerable process intensification.</p
Atomic-resolution characterization on the structure of strontium doped barium titanate nanoparticles
Single-Stimulus Dual-Drug Sensitive Nanoplatform for Enhanced Photoactivated Therapy
Photoactivated
therapy has become a complementary and attractive
modality for traditional cancer treatment. Herein, we demonstrated
a novel single-stimulus dual-drug sensitive nanoplatform, Cur-loaded
Dex–PtÂ(N<sub>3</sub>) nanoparticles (Cur@DPNs) for enhanced
photoactivated therapy. The developed Cur@DPNs could be photoactivated
by UVA light to simultaneously generate instant reactive oxygen species
from Cur for fast photodynamic therapy and release lasting PtÂ(II)
from PtÂ(N<sub>3</sub>) for long-acting photochemotherapy. Compared
with small free drugs and individual photoactivated therapy, Cur@DPNs
exhibited enhanced photoactivated cytotoxicity and in vivo antitumor
efficacy with low systemic toxicity accompanied. Therefore, the single-stimulus
dual-drug sensitive nanoplatform is convinced to be a promising strategy
for multidrug delivery, site-selective and combinational photoactivated
therapy in the near future