Amorphous Iridium Oxide-Integrated Anode Electrodes with Ultrahigh Material Utilization for Hydrogen Production at Industrial Current Densities

Herein,ionomer-free amorphous iridium oxide(IrO_(x))thin electrodes are first developed as highly active anodes for proton exchange membrane electrolyzer cells(PEMECs)via low-cost,environmentally friendly,and easily scalable electrodeposition at room temperature.Combined with a Nafion 117 membrane,the IrO_(x)-integrated electrode with an ultralow loading of 0.075 mg cm^(-2)delivers a high cell efficiency of about 90%,achieving more than 96%catalyst savings and 42-fold higher catalyst utilization compared to commercial catalyst-coated membrane(2 mg cm^(-2)).Additionally,the IrO_(x)electrode demonstrates superior performance,higher catalyst utilization and significantly simplified fabrication with easy scalability compared with the most previously reported anodes.Notably,the remarkable performance could be mainly due to the amorphous phase property,sufficient Ir^(3+)content,and rich surface hydroxide groups in catalysts.Overall,due to the high activity,high cell efficiency,an economical,greatly simplified and easily scalable fabrication process,and ultrahigh material utilization,the IrO_(x)electrode shows great potential to be applied in industry and accelerates the commercialization of PEMECs and renewable energy evolution.

Singlet oxygen synergistic surface-adsorbed hydroxyl radicals for phenol degradation in CoP catalytic photo-Fenton

In recent years,there have been numerous studies on Fenton or Fenton-like reactions mediated by nonfree radicals such as singlet oxygen(1O_(2));however,there are few studies on the synergistic effect of 1O_(2) and free radicals on the degradation of organic molecules,such as phenol in Fenton reaction.In this study,a cocatalyst,CoP,commonly used in photocatalysis was synthesized using a simple two-step method,and a CoP/Fe^(2+)/AM1.5 system was constructed by introducing Fe^(2+)and simulated sunlight(AM1.5)irradiation.The newly constructed CoP/Fe^(2+)/AM1.5 system could effectively degrade various organic pollutants,including dyes,phenols,and antibiotics.Radical quenching experiments and electron paramagnetic resonance detection confirmed that there were three reactive oxygen species(ROS)in the CoP/Fe^(2+)/AM1.5 system,including·OH_(ads),·O_(2)^(-),and 1O_(2).Further,combined with the liquid chromatogram of phenol,its intermediate products,and the fluorescence diagram of o-hydroxybenzoic acid,it can be concluded that a synergistic effect exists between 1O_(2) and the surface-adsorbed·OH_(ads) in the CoP/Fe^(2+)/AM1.5 system.The controllable formation of surface 1O_(2) and·OH_(ads) was achieved through the oxidation(Co^(3+))and reduction(Pδ−)centers exposed on the CoP surface,and the synergistic effect between them results in phenol’s hydroxylation,ring-opening,and degradation.The study of this new mechanism provides a new perspective for revealing the surface interface reaction between ROS and organic pollutants.

草酸二芳基酯-过氧化氢化学发光体系的原理与应用

草酸二芳基酯-过氧化氢化学发光体系是一种原理简单、效果明显、趣味性强的化学发光体系。通过体系中的染料将反应的化学能转变为光能,广泛应用于发光玩具、紧急照明、搜寻救援等领域。根据所使用染料的不同,化学发光可以发出不同颜色的可见光以及肉眼不可见的红外光。本科普实验通过多种化学发光染料,介绍了化学发光的原理和红、绿、蓝、红外发光的波长范围,以及展示了利用红光、绿光、蓝光实现多种颜色发光的原理。本文设计了不同染料的混合发光、火山喷发模拟、自制化学发光荧光笔、粉笔彩色发光、自制荧光棒等多组化学发光科普实验和互动环节,寓教于乐,生动有趣。

Analysis on Current Situation and Measures of International Talent Nurturing in Latin American Colleges and Universities among the Chengdu- Chongqing Economic Circle

With the proposal of the Belt and Road Initiative,the exchanges and cooperation between China and Latin America in various fields are rapidly warming up,and both sides actively promote cross-regional,cross-country,and cross-cultural international talent education.The proposal of Chengdu-Chongqing economic circle coincides with a great change unseen in a century.Under the background of far-reaching and complicate changes in both domestic and international environment,the trend of all-round cooperation between the Chengdu-Chongqing economic circle and Latin American countries and regions has been deepening.However,the quantity,quality,level and economic cross-regional training of regional Latin American international talents still present some structural imbalances and challenges compared with the development of trans-regional economic cooperation.Based on this,the study will focus on the current situation of nurturing international talents in Latin America by the Chengdu-Chongqing economic circle,and provide suggestions for the joint training of talents in Latin America and China-Latin America educational cooperation and exchanges.It will also make for jointly build a China-Latin America Community of Shared Future and respond to the Belt and Road initiative with a certain reference value.

Preparation and Electrochemical Performance of Si@void@NC Composite with a Tunable Nitrogen Doping Content in the Carbon Layer

A strategy for the preparation nitrogen-doped carbon encapsulated Si nanocomposite with a void layer(Si@void@NC)is proposed,in which the nitrogen doping content in the carbon layer is tunable.Aniline and ortho-phenylenediamine are both selected as the nitrogen,carbon sources and co-polymerized on Si@SiO_(2),in which SiO_(2)is functionalized as a void template.SEM and TEM observation show that Si nanoparticles are encapsulated in a hollow and interconnected carbon cages with a thickness of less than 10 nm,which is inclined to agglomerate together to form larger particles in micrometer scale.The variation of mole ratio of aniline and ortho-phenylenediamine will enable the change of nitrogen doping level in the carbon layer and ranges from 3.2%to 8.4%.The nitrogen is doped into the carbon framework in the form of pyridinic,pyrrolic and graphitic nitrogen.Electrochemical tests indicate that the nitrogen content influences the SEI formation and the lithiation of Si nanoparticles.The potential for the decomposition of electrolyte to form SEI film and the alloying of Si-Li negatively shift when the nitrogen doping content is increased.Furthermore,the cycling performance of Si@void@NC is improved when raising the nitrogen content in the carbon.And the optimal nitrogen content is 7.5%,which is corresponding to the mole ratio of aniline to ortho-phenylenediamine is 5:5.

Direct synthesis of high-quality perovskite nanocrystals on a flexible substrate and deterministic transfer

Solid-state perovskite nanocrystals are promising coherent light sources, as there is optical feedback within the crystal structure. In order to utilize the high performance of perovskites for on-chip applications, or observe new physical phenomena, these crystals must be integrated with pre-fabricated electronic or photonic structures. However, the material's fragility has made the deterministic transfer a great challenge thus far. Here, we report the first deterministic transfer of perovskite nanocrystals with sub-micron accuracy. Cesium lead halide(CsPbI_3) nanocrystals were directly synthesized on flexible polydimethylsiloxane(PDMS) stamps via chemical vapor deposition(CVD) and subsequently transferred onto arbitrary substrates/structures. We demonstrated the transfer of a CsPbI_3 crystalline nanoplate(NP)onto an 8 mm fiber core and achieved single-mode whispering gallery mode lasing. Our method can be extended to a variety of other arbitrary substrates(e.g., electrodes, photonic structures, micromechanical systems), laying the foundations for previously unattainable opportunities in perovskites-based devices.

FT-ICR mass spectrometry for molecular characterization of water-insoluble organic compounds in winter atmospheric fine particulate matters

Water-insoluble organic compounds(WIOCs)are an important fraction of atmospheric fine particulate matters(PM_(2.5)),which could affect the climate system and threaten human health potentially.In this study,molecular characterization of WIOCs in PM_(2.5) were investigated by 15 T Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS)with atmospheric pressure photoionization(APPI)source in positive ion mode.A total of 2573 and1875 molecular formulas were identified in WIOCs extracted by dichloromethane,which were collected in hazy and normal days,respectively.The identified molecular formulas were further classified into four major subgroups,including CH,CHN,CHO and CHNO compounds.CHO compounds predominated in WIOCs,accounting for more than 60%in both samples.CHNO compounds(26.6%)and CH compounds(16.1%)were the second highest subgroups in WIOCs from the hazy days and normal days,respectively.The relative abundance and number of nitro-substituted aromatic compounds were significantly higher in hazy days than in normal days.The molecular composition of WIOCs was more complex in hazy days while more aromatic compounds were identified in normal days.

Enhanced mixing efficiency for a novel 3D Tesla micromixer for Newtonian and non-Newtonian fluids

The fabrication of constructs with gradients for chemical,mechanical,or electrical composition is becoming critical to achieving more complex structures,particularly in 3D printing and biofabrication.This need is underscored by the complexity of in vivo tissues,which exhibit heterogeneous structures comprised of diverse cells and matrices.Drawing inspiration from the classical Tesla valve,our study introduces a new concept of micromixers to address this complexity.The innovative micromixer design is tailored to enhance the re-creation of in vivo tissue structures and demonstrates an advanced capability to efficiently mix both Newtonian and non-Newtonian fluids.Notably,our 3D Tesla valve micromixer achieves higher mixing efficiency with fewer cycles,which represents a significant improvement over the traditional mixing method.This advance is pivotal for the field of 3D printing and bioprinting,and offers a robust tool that could facilitate the development of gradient hydrogel-based constructs that could also accurately mimic the intricate heterogeneity of natural tissues.

Elucidating the impact of the ionomer equivalent weight on a platinum group metal-free PEMFC cathode via oxygen limiting current

Leveraging the interactions between ionomer and catalyst can increase the performance of proton exchangemembrane fuel cells.The impacts of the equivalent weight(EW)of perfluorosulfonic acid-based ionomers on the platinum group metal-free electrode structure and fuel cell performance have not been fully explored.Four membrane electrode assemblies(MEAs)were prepared by using a commercial Fe-N-C catalyst,two perfluorosulfonic acid ionomers with different EWs,that is,Aquivion 720(A720)and Nafion 1100(N1100),and two ionomer-tocatalyst(I/C)ratios.The four MEAswere characterized to understand the impact of the ionomer EW and content on the capacitance,proton conductivity,and mass transport on the cathode.The mass transport resistance was measured for the first time using a new oxygen reduction reaction limiting current method enabling to couple the effects of oxygen diffusion with liquid water generation.Low EW ionomer combined with a moderate I/C results in improved performance due to its enhanced proton conductivity.However,when used at high I/C,it can cause severewater flooding at high current density due to the enhanced liquid water uptake,especially at high relative humidity,resulting in lower catalyst utilization and higher mass transport resistance.

De Novo Design and Synthesis of Polypeptide Immunomodulators for Resetting Macrophage Polarization

Modulating the extracellular matrix microenvironment is critical for achieving the desired macrophage phenotype in immune investigations or tumor therapy.Combining de novo protein design and biosynthesis techniques,herein,we designed a biomimetic polypeptide self-assembled nano-immunomodulator to trigger the activation of a specific macrophage phenotype.It was intended to be made up of(GGSGGPGGGPASAAANSASRATSNSP)n,the RGD motif from collagen,and the IKVAV motif from laminin.The combination of these domains allows the biomimetic polypeptide to assemble into extracellular matrix-like nanofibrils,creating an extracellular matrix-like milieu for macrophages.Furthermore,changing the concentration further provides a facile route to fine-tune macrophage polarization,which enhances antitumor immune responses by precisely resetting tumor-associated macrophage immune responses into an M1-like phenotype,which is generally considered to be tumor-killing macrophages,primarily antitumor,and immune-promoting.Unlike metal or synthetic polymer-based nanoparticles,this polypeptide-based nanomaterial exhibits excellent biocompatibility,high efficacy,and precise tunability in immunomodulatory effectiveness.These encouraging findings motivate us to continue our research into cancer immunotherapy applications in the future.