Search

Developing low-cost and high efficient electrocatalysts for both oxygen and hydrogen evolution reaction in an alkaline electrolyte toward overall water splitting is still a significant challenge. Here, a novel hierarchically heterostructured catalyst composed of ultrasmall Mo 2 C and metallic Co nanoparticles confined within a carbon layer is produced by a facile phase separation strategy. During thermal reduction of CoMoO 4 nanosheets in CO ambient, in-situ generated nanoscale Co and ultrafine Mo 2 C conformally encapsulated in a conductive carbon layer. In addition, some carbon nanotubes catalyzed by Co nanoparticles vertically grew on its surface, creating 3D interconnected electron channels. More importantly, the integrated C@Mo 2 C/Co nanosheets assembled into the hierarchical architecture, providing abundant active surface and retaining the structural integrity. Benefiting from such unique structure, the constructed hierarchical heterostructure shows low overpotentials of 280 mV and 145 mV to reach a current density of 10 mA cm−2 for OER and HER in an alkaline electrolyte. Furthermore, the symmetrical electrolyzer assembled with catalyst exhibits a small cell voltage of 1.67 V at 10 mA cm−2 in addition to outstanding durability, demonstrating the great potential as a high efficient bifunctional electrocatalyst for overall water splitting. Image 1 • A novel hierarchically hetestructured C@Mo 2 C/Co electrocatalyst is constructed. • Ultrafine Mo 2 C and Co nanoparticles are conformally embedded in carbon matrix. • The carbon matrix acts as conductive substrate and structure support. • The C@Mo 2 C/Co electrocatalyst shows superior HER and OER performance in 1M KOH. • The C@Mo 2 C/Co presents bifunctionality of 1.67 V at 10 mA cm-2 for water splitting. [ABSTRACT FROM AUTHOR]

α-MnO 2 nanotubes and their supported Au-Pd alloy nanocatalysts were prepared using hydrothermal and polyvinyl alcohol-protected reduction methods, respectively. Their catalytic activity for the oxidation of toluene/ m -xylene, acetone/ethyl acetate, acetone/ m -xylene and ethyl acetate/ m -xylene mixtures was evaluated. It was found that the interaction between Au-Pd alloy nanoparticles and α-MnO 2 nanotubes significantly improved the reactivity of lattice oxygen, and the 0.91 wt.% Au 0.48 Pd/α-MnO 2 nanotube catalyst outperformed the α-MnO 2 nanotube catalyst in the oxidation of toluene, m -xylene, ethyl acetate and acetone. Over the 0.91 wt.% Au 0.48 Pd/α-MnO 2 nanotube catalyst, (i) toluene oxidation was greatly inhibited in the toluene/ m -xylene mixture, while m -xylene oxidation was not influenced; (ii) acetone and ethyl acetate oxidation suffered a minor impact in the acetone/ethyl acetate mixture; and (iii) m -xylene oxidation was enhanced whereas the oxidation of the oxygenated VOCs (volatile organic compounds) was suppressed in the acetone/ m -xylene or ethyl acetate/ m -xylene mixtures. The competitive adsorption of these typical VOCs on the catalyst surface induced an inhibitive effect on their oxidation, and increasing the temperature favored the oxidation of the VOCs. The mixed VOCs could be completely oxidized into CO 2 and H 2 O below 320°C at a space velocity of 40,000 mL/(g·hr). The 0.91 wt.% Au 0.48 Pd/α-MnO 2 nanotube catalyst exhibited high catalytic stability as well as good tolerance to water vapor and CO 2 in the oxidation of the VOC mixtures. Thus, the α-MnO 2 nanotube-supported noble metal alloy catalysts hold promise for the efficient elimination of VOC mixtures. [ABSTRACT FROM AUTHOR]

Aggregation‐induced emission luminogens (AIEgens) as a new class of optical probes for two‐photon imaging (2PI) have attracted extensive attention in the research community. However, their non‐radiative energy dissipation plays a non‐negligible role in energy consumption, thereby weakening their performance in 2PI. Exploration of a facile and general approach to control the energy relaxation pathways is thus a fascinating yet significantly challenging task. To address this concern, an organic doping method is proposed herein by using TPE‐Br as the doping AIEgen and MeOTTMN as the functional AIEgen. With increased amount of doping molecules, a steadily strengthened brightness (up to 29‐fold of quantum yield) is observed at the expense of reactive oxygen species production. Remarkably, an ultradeep imaging depth of 1000 µm in a mouse brain is realized via 2PI using the heavily organic‐doped AIEgen(ODA) nanoparticles (NPs). Such result is far superior to the imaging depth of 156 µm enabled by MeOTTMN NPs. The safe use of ODA NPs is further evaluated by in vitro and in vivo toxicity assessment. This study thus provides an attractive paradigm to control the energy relaxation of AIEgen NPs and maximize their performance in 2PI while circumventing the difficulties in molecular engineering. [ABSTRACT FROM AUTHOR]

Abstract: Recently, the preparation of nanographitic materials have become one of the most active research fields, especially after the rise of graphene. Crystalline graphitic nanosheets have been prepared on the copper substrates by the energetic-beam deposition of carbon nanoclusters. The thicknesses of the nanosheets are at the scale of nanometer, as determined by the Scanning Electron Microscope measurement of curled nanosheets. The characterization by Raman scattering and the Electron Backscattered Diffraction demonstrated the graphitic structure of the nanosheets. Comparable growth was also carried out with the conditions of silicon substrates or free deposition. No similar nanosheet was found. The lattice match and the beam energy are attributed to enhance the graphitic growth. [Copyright &y& Elsevier]

Aggregation-induced emission, brain vasculature, energy relaxation, organic doping, two-photon imaging Keywords: aggregation-induced emission; brain vasculature; energy relaxation; organic doping; two-photon imaging EN aggregation-induced emission brain vasculature energy relaxation organic doping two-photon imaging 1 1 1 07/05/23 20230701 NES 230701 In article number 2300255, Yuanyuan Shen, Zhourui Xu, Gaixia Xu, and colleagues develop an organic doping method to boost the two-photon action cross-section of aggregation-induced emission luminogens (AIEgens) by providing a hydrophobic and rigid nano-environment. Controlling the Energy Relaxation: Organic Doping in AIEgen Nanoparticles for Highly Enhanced Intravital Two-Photon Imaging (Advanced Optical Materials 13/2023). [Extracted from the article]

Abstract: Non-invasive assay for the early stage diagnosis of methicillin resistant Staphylococcus aureus ( MRSA ) related pneumonia is of great clinical importance and still a great challenge. In this paper, we reported a novel kind of Au@Ag core–shell theranostic nanoparticles (NPs) conjugated with MRSA specific antibody on their surface. Compared with the raw Au@Ag NPs, these antibody modified NPs (AAMA NPs) showed 10.66 fold enhancement targeting to the MRSA in vitro. In vivo target efficacy was measured with rats bearing pneumonia induced by different pathogens. Computed tomography (CT) results revealed that these AAMA NPs had higher CT contrast enhancement (498 HU), than those of raw Au@Ag and Omnipaque (oth <100 HU). In addition, lesions labeled by AAMA NPs could be distinguished from lung parenchyma by taking advantage of spectra CT. Bio-distribution analysis confirmed that these AAMA NPs accumulated in the MRSA rich site. Both BAL and Elisa assays indicated that these AAMA NPs greatly alleviated the inflammation reaction by reducing bacterial proliferation and cytokine production. Pathological study showed that these NPs exerted negligible long term cytotoxicity in vivo. [Copyright &y& Elsevier]