Nitrogen-doped carbon confined NiFe–NiFeP nanocubes immobilized on carbon nanotube as an efficient electrocatalyst for oxygen evolution reaction

The future sustainable energy related application, especially Zn-air batteries (ZABs) and electrochemical water splitting to produce hydrogen, are limited by oxygen evolution reaction (OER). Transition metal phosphides have excellent catalytic activity for OER, but their poor conductivity and bad stability still require to be solved. Herein, the nitrogen-doped carbon (NC) confined NiFe–NiFeP nanocubes immobilized on carbon nanotube (CNT) (NiFe–NiFeP@NC/CNT) is fabricated by employing NiFe-Prussian Blue Analogs (NiFe–PBAs) nanocubes and CNT composite as precursor, and subsequent polydopamine (PDA) coating, carbonization and partial phosphorization. Profiting from its unique “nanonecklaces” structure with conductive CNT and ordered NiFe–NiFeP@NC nanocubes, NiFe–NiFeP@NC/CNT provides an efficient electron transfer path and uniformly dispersed active sites for OER process. The optimized NiFe–NiFeP@NC/CNT exhibits a low overpotential of 228 (328) mV at 10 (100) mA cm⁻² and high durability. Furthermore, the NiFe–NiFeP@NC/CNT || Pt/C requires 1.51 V to realize 20 mA cm⁻² for overall water spitting. And the ZAB assembled with NiFe–NiFeP@NC/CNT shows excellent discharge-charge stability for 240 h.     

Comprehensive analysis on the effect of lube oil on particle emissions through gas exhaust measurement and chemical characterization of condensed exhaust from a DI SI engine fueled with hydrogen

This research study aims to investigate the causes of the particles emitted by a spark ignition engine fueled with hydrogen. The experiments were carried out on a single cylinder 250 cm³ direct injection spark ignition engine. Two operating conditions at 2000 rpm both full and low load, representative of typical urban conditions, were investigated. A physical characterization of the particles, size and number, was performed through an Engine Exhaust Particle Sizer coupled to a single diluter. Chemical characterization was carried out on the condensed exhaust. The simultaneous analysis of the physical properties and their chemical characterization allows to point out not only the role of the oil on the particle emissions but also to give an important information on its state/composition, if it was unburned and oxidized. Particles were detected with conventional spectrometer at low load while at high load the noise signal ratio is too high to distinguish the presence of particles. More detailed chemical techniques highlighted the presence of PAH, alkyl-PAHs, oxy-PAHs and unburned hydrocarbon in the exhaust due to the mineral oil.     

Enhanced hydrogen storage properties of Ti–Cr–Nb alloys by melt-spin and Mo-doping

Ti–Cr–Nb hydrogen storage alloys with a body centered cubic (BCC) structure have been successfully prepared by melt-spin and Mo-doping. The crystalline structure, solidification microstructural evolution, and hydrogen storage properties of the corresponding alloys were characterized in details. The results showed that the hydrogen storage capacity of Ti–Cr–Nb ingot alloys increased from 2.2 wt% up to around 3.5 wt% under the treatment of melt-spin and Mo-doping. It is ascribed that the single BCC phase of Ti–Cr–Nb alloys was stabilized after melt-spin and Mo-doping, which has a higher theoretical hydrogen storage site than the Laves phase. Furthermore, the melt-spin alloy after Mo doping can further effectively increase the de-/absorption plateau pressure. The hydrogen desorption enthalpy change ΔH of the melt-spin alloy decreased from 48.94 kJ/mol to 43.93 kJ/mol after Mo-doping. The short terms cycling test also manifests that Mo-doping was effective in improving the cycle durability of the Ti–Cr–Nb alloys. And the BCC phase of the Ti–Cr–Nb alloys could form body centered tetragonal (BCT) or face center cubic (FCC) hydride phase after hydrogen absorption and transform to the original BCC phase after desorption process. This study might provide reference for developing reversible metal hydrides with favorable cost and acceptable hydrogen storage characteristics.     

Rational design of PANI incorporated PEG capped CuO/TiO2 for electrocatalytic hydrogen evolution and supercapattery applications

Synthesis of efficient electrocatalysts for energy applications is a major area scientists are currently focusing on to address the twin challenges of energy shortfall and the production of clean energy. Herein, an efficient electrocatalyst, polyaniline incorporated with polyethylene glycol capped CuO/TiO₂ is prepared, which is effective in hydrogen evolution reactions and energy storage applications. The characterizations like XPS, XRD, FT-IR, FE-SEM, HR-TEM, and BET have been carried out to confirm the successful formation of the synthesized PANI/CuO/TiO₂ composite. At 10 mA/cm² current density, the prepared composite exhibits a lesser overpotential of 536 mV and 1587.2 C/g at 1 A/g as the specific capacity. The electrode prepared using the PANI/CuO/TiO₂ composite also shows cyclic stability up to 2000 cycles. The synthesized composite is an efficient electrocatalyst for energy related applications.     

Cerium and carbon-sulfur codoped mesoporous TiO2 nanocomposites for boosting visible light photocatalytic activity

Ce and C-S codoped mesoporous TiO₂ nanocomposites were synthesized via a sol-gel method integrated with an evaporation-induced self-assembly approach.The basic physicochemical characteristics of the synthetic samples were analyzed via a series of characterization techniques.The results reveal that C-S and Ce codoping on mesoporous TiO₂ enhances the photocatalytic activity owing to the synergistic effect caused by narrowing the band gap,enhancing adsorption,trapping and tran...     

Effect of MgCl2 on electrophoretic deposition of TbF3 powders on Nd-Fe-B sintered magnet

Using electrophoretic deposition(EPD) method,the TbF₃ powders were deposited on the surface of sintered Nd-Fe-B magnets,and the effects of MgCl₂ on electrophoretic deposition and grain boundary diffusion were investigated.The results show that addition of 5 wt% MgCl₂ can significantly improve the EPD efficiency and improve the adhesion of the coating by releasing local stress through the formation of special gully morphology.Combining with Biesheuvel equation,the...     

Luminescence enhancement of Cr3+ doped garnet phosphor for high-performance LED towards smart NIR light source

Cr³⁺ doped phosphor shows great potential for near-infrared (NIR) light-emitting diodes (LED), but it suffers from low quantum efficiency and poor thermal stability. Herein, a novel Cr³⁺ doped broadband NIR garnet Ca₃Sc₂Ge₃O₁₂ phosphor was developed. The multisite structure of the emission band is investigated by site-selective spectroscopy and is attributed to the octahedral Cr³⁺ perturbed by defects. Moreover, we propose different strategies to enhance the luminescence of the phosphor, including enhancement of crystallinity and elimination of defects. Compared with the initial sample, the emission intensity of the optimized phosphor is improved for 8.6 times. The optimal Ca₃Sc₂Ge₃O₁₂: 0.06Cr³⁺ phosphor exhibits excellent thermal stability. At 423 K, the integral emission intensity of the optimal sample remains 94.7% of that at room temperature. Finally, high-performance NIR LED was fabricated using a blue LED and the title phosphor. The packaged LED lamp has high radiance (109.3 mW@300 mA) and photoelectric efficiency (15.96%@40 mA). Our study not only provides a boulevard for enhancing the luminescence of Cr doped NIR phosphor, but also gives a new perspective for understanding the multisite luminescence of Cr³⁺ in garnet host.     

Phase precipitation and magnetic properties of melt-spun ternary Gd2Fe14B alloy and advantages of gadolinium substitution in Y2Fe14B alloy

To take the advantage of gadolinium(Gd) in developing and manufacturing RE-permanent magnets,the magnetic properties and phase precipitation behavior of Gd₂Fe₁₄B alloys prepared by melt spinning were investigated in this work.The results show that optimally direct quenched nanocrystalline Gd₂Fe₁₄B alloy exhibits the magnetic properties with remanence J_r of 0.51 T,coercivity H_c of 187 kA/m,and maximum energy product(BH)_max     

Surface-Engineered Extracellular Vesicles with CDH17 Nanobodies to Efficiently Deliver Imaging Probes and Chemo-Photothermal Drugs for Gastric Cancer Theragnostic

Extracellular vesicles (EVs) are widely used as natural nanoparticles to deliver various cargos for disease diagnosis and therapy. However, unmodified EVs cannot efficiently transport the cargos to desired sites due to non-specific uptake. Here, a delivery system is designed to display nanobodies against cadherin 17 (CDH17) on the surface of EVs isolated from HEK-293 cells and loaded with dye Indocyanine green (ICG) and/or anti-cancer drug dinitroazetidine derivative RRx-001, a blocker for CD47/ signal regulatory protein alpha (SIRPα) axis. CDH17 is a promising target for gastric cancer (GC) therapy. In this study, ICG loaded in the EVs engineered with CDH17 nanobodies can realize rapid tumor imaging in a CDH17-positive GC model and can produce significant anti-tumor photothermal therapeutic (PTT) effect after irradiation. Meanwhile, PTT effect can induce immunogenic cell death and macrophage polarization from M2 to M1 phenotype. The engineered EVs loaded with RRx-001 can significantly repress GC tumor growth. Finally, dual loading of ICG/RRx-001 in engineered EVs show maximal anti-tumor efficacy in both cancer cell and patient-derived GC models after only single injection. Collectively, CDH17 nanobody-functionalized EVs loaded with ICG and/or RRx-001 hold great promise to image and treat GC by combining fluorescent dye-induced PTT with chemotherapy.     

Suppression of inner energy dissipation in Yb-doped NaErF4 upconversion nanocrystals through an energy cycling strategy

Suppression of the inner energy dissipation,related to the lattice phonons and inner defects,in lanthanide doped upco nversion luminescent materials remains a formidable challenge.Herein,we reveal an energy cycling strategy capable of suppressing the inner energy dissipation in lanthanide doped upconversion nanocrystals.Yb³⁺ ions were introduced in Er³⁺ heavily doped nanocrystals as an energy reservoir to compete with the inner energy dissipation.The detailed energy cycling...