In Situ Symbiosis of Cerium Oxide Nanophase for Enhancing the Oxygen Electrocatalysis Performance of Single-Atom Fe─N─C Catalyst with Prolonged Stability for Zinc-Air Batteries.

The Fenton reaction, induced by the H2O2 formed during the oxygen reduction reaction (ORR) process leads to significant dissolution of Fe, resulting in unsatisfactory stability of the iron-nitrogen-doped carbon catalysts (Fe-NC). In this study, a strategy is proposed to improve the ORR catalytic activity while eliminating the effect of H2O2 by introducing CeO2 nanoparticles. Transmission electron microscopy and subsequent characterizations reveal that CeO2 nanoparticles are uniformly distributed on the carbon substrate, with atomically dispersed Fe single-atom catalysts (SACs) adjacent to them. CeO2@Fe-NC achieves a half-wave potential of 0.89 V and a limiting current density of 6.2 mA cm-2, which significantly outperforms Fe-NC and commercial Pt/C. CeO2@Fe-NC also shows a half-wave potential loss of only 1% after 10 000 CV cycles, which is better than that of Fe-NC (7%). Further, H2O2 elimination experiments show that the introduction of CeO2 significantly accelerate the decomposition of H2O2. In situ Raman spectroscopy results suggest that CeO2@Fe-NC significantly facilitates the formation of ORR intermediates compared with Fe-NC. The Zn-air batteries utilizing CeO2@Fe-NC cathodes exhibit satisfactory peak power density and open-circuit voltage. Furthermore, theoretical calculations show that the introduction of CeO2 enhances the ORR activity of Fe-NC SAC. This study provides insights for optimizing SAC-based electrocatalysts with high activity and stability.

High-Stability RuNi/C Electrocatalyst for Efficient Hydrogen Oxidation Reaction in Alkaline Condition.

The Ru-based catalyst for hydrogen oxidation reaction (HOR) with remarkable activity and reliability at high potential range remains a formidable challenge. Herein, the RuNi/C nanoparticles are customized, in which NiRu alloy is tightly wrapped with a carbon layer, delivering 2.2-fold and 8.3-fold enhancement in kinetic current density than that of commercial Pt/C and Ru/C, respectively. Notably, the current density maintains 2.93 mA cm-2 disk at 0.6 V vs RHE, which effectively improves the stability of Ru-based catalysts at high voltage. The NiRu alloy triggers electron redistribution between two metal elements and regulates the surface adsorption performance, coupled with a tightly wrapped outer carbon layer which is in situ formed with alloy as a good conductor of electronic and protection from the electrolyte. This work not only provides a novel electrocatalyst for efficient HOR with its potential for industrial application but also opens up a new avenue for designing highly active catalytic systems.

Pencil-paper on-skin electronics.

Pencils and papers are ubiquitous in our society and have been widely used for writing and drawing, because they are easy to use, low-cost, widely accessible, and disposable. However, their applications in emerging skin-interfaced health monitoring and interventions are still not well explored. Herein, we report a variety of pencil-paper-based on-skin electronic devices, including biophysical (temperature, biopotential) sensors, sweat biochemical (pH, uric acid, glucose) sensors, thermal stimulators, and humidity energy harvesters. Among these devices, pencil-drawn graphite patterns (or combined with other compounds) serve as conductive traces and sensing electrodes, and office-copy papers work as flexible supporting substrates. The enabled devices can perform real-time, continuous, and high-fidelity monitoring of a range of vital biophysical and biochemical signals from human bodies, including skin temperatures, electrocardiograms, electromyograms, alpha, beta, and theta rhythms, instantaneous heart rates, respiratory rates, and sweat pH, uric acid, and glucose, as well as deliver programmed thermal stimulations. Notably, the qualities of recorded signals are comparable to those measured with conventional methods. Moreover, humidity energy harvesters are prepared by creating a gradient distribution of oxygen-containing groups on office-copy papers between pencil-drawn electrodes. One single-unit device (0.87 cm2) can generate a sustained voltage of up to 480 mV for over 2 h from ambient humidity. Furthermore, a self-powered on-skin iontophoretic transdermal drug-delivery system is developed as an on-skin chemical intervention example. In addition, pencil-paper-based antennas, two-dimensional (2D) and three-dimensional (3D) circuits with light-emitting diodes (LEDs) and batteries, reconfigurable assembly and biodegradable electronics (based on water-soluble papers) are explored.

Multiscale porous elastomer substrates for multifunctional on-skin electronics with passive-cooling capabilities.

In addition to mechanical compliance, achieving the full potential of on-skin electronics needs the introduction of other features. For example, substantial progress has been achieved in creating biodegradable, self-healing, or breathable, on-skin electronics. However, the research of making on-skin electronics with passive-cooling capabilities, which can reduce energy consumption and improve user comfort, is still rare. Herein, we report the development of multifunctional on-skin electronics, which can passively cool human bodies without needing any energy consumption. This property is inherited from multiscale porous polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) supporting substrates. The multiscale pores of SEBS substrates, with characteristic sizes ranging from around 0.2 to 7 µm, can effectively backscatter sunlight to minimize heat absorption but are too small to reflect human-body midinfrared radiation to retain heat dissipation, thereby delivering around 6 °C cooling effects under a solar intensity of 840 W⋅m-2 Other desired properties, rooted in multiscale porous SEBS substrates, include high breathability and outstanding waterproofing. The proof-of-concept bioelectronic devices include electrophysiological sensors, temperature sensors, hydration sensors, pressure sensors, and electrical stimulators, which are made via spray printing of silver nanowires on multiscale porous SEBS substrates. The devices show comparable electrical performances with conventional, rigid, nonporous ones. Also, their applications in cuffless blood pressure measurement, interactive virtual reality, and human-machine interface are demonstrated. Notably, the enabled on-skin devices are dissolvable in several organic solvents and can be recycled to reduce electronic waste and manufacturing cost. Such on-skin electronics can serve as the basis for future multifunctional smart textiles with passive-cooling functionalities.

Natural gas spot price prediction research under the background of Russia-Ukraine conflict - based on FS-GA-SVR hybrid model.

The ongoing Russia-Ukraine conflict has led to significant upheaval in the worldwide natural gas sector. Accurate natural gas price forecasting, as an essential tool for mitigating market uncertainty, plays a crucial role in commodity trading and regulatory decision-making. This study aims to develop a hybrid forecasting model, the FS-GA-SVR model, which integrates feature selection (FS), genetic algorithm (GA), and support vector regression (SVR) to investigate Henry Hub natural gas price prediction amidst the Russia-Ukraine conflict. The results show that: (1) The feature selection automates model input variable selection, decreasing the time required while improving the model's accuracy. (2) The use of genetic algorithm for selecting support vector regression hyperparameters significantly improves the accuracy of natural gas price predictions. The algorithm leads to a decrease of approximately 70% in measurement indicators. (3) During the Russia-Ukraine conflict, the FS-GA-SVR hybrid model demonstrates more consistent and accurate predictions for natural gas spot prices than the base SVR model. This study serves as a valuable theoretical reference for energy policymakers and natural gas market investors worldwide, supporting their ability to anticipate fluctuations in natural gas prices.

Stabilizing Pt Single Atoms through Pt-Se Electron Bridges on Vacancy-enriched Nickel Selenide for Efficient Electrocatalytic Hydrogen Evolution.

Rational design of Pt single-atom catalysts provides a promising strategy to significantly improve the electrocatalytic activity for hydrogen evolution reaction. In this work, we presented a novel and efficient strategy for utilizing the low electron-density region of substrate to effectively trap and confine high electron-density metal atoms. The Pt single-atom catalyst supported by nickel selenide with rich vacancies was prepared via a hydrothermal-impregnation stepwise approach. Through experimental testation and DFT theoretical calculation, we confirm that Pt single atoms are well distributed at cationic vacancies of nickel selenide with loading amount of 3.2 wt. %. Moreover, the atomic Pt combined with the high electronegative Se to form Pt-Se bond as a "bridge" between single atoms and substrate for fast electron translation. This novel catalyst shows an extremely low overpotential of 45 mV at 10 mA cm-2 and an excellent stability over 120 h. Furthermore, the nickel selenide supported Pt SACs exhibits long-term stability for practical application, which maintains a high current density of 390 mA cm-2 over 80 h with a retention of 99 %. This work points a promising direction for designing single atoms catalysts with high catalytic activity and stability for advanced green energy conversion technologies.

Can digital economy development contribute to carbon emission reduction? Evidence from China.

With the rapid growth of the digital economy, it is essential to understand its impact on carbon emissions reduction. This study uses provincial panel data from China during 2011-2019 to construct a moderating mediating effect model and a spatial panel Durbin model to examine the relationship between the digital economy and carbon emissions reduction. This study analyzes the mediating effect of the energy structure on the digital economy's impact on carbon emission reduction, and the spatial effect and regional heterogeneity of the digital economy's impact on carbon emission reduction. The findings indicate that the development of the digital economy can effectively promote regional carbon emission reductions, both directly and indirectly, with a significant spatial spillover effect. Second, the energy structure plays a significant mediating role in promoting carbon emission reduction in the digital economy, and the industrial structure has a positive moderating effect. Third, the impact of the digital economy on carbon emissions reduction has significant regional heterogeneity, and the inhibitory effect of the digital economy is more effective in the central and western provinces. This study provides a theoretical reference for achieving high-quality development of the digital economy while promoting carbon emissions reduction.

In Situ Interfacial Passivation in Aqueous Electrolyte for Mg-Air Batteries with High Anode Utilization and Specific Capacity.

Mg-air batteries are a promising new generation of batteries because they can operate in neutral electrolytes that are safe and nontoxic. However, the high corrosion and low utilization of Mg anodes in Mg-air batteries result in low specific capacity and severe self-discharge. In this study, an Mg(OTf)2 -based aqueous electrolyte is developed, which addresses these issues by reducing the contact of the Mg anode with water molecules from the hydrophobic -CF3 groups and forming an MgF2 protective layer. The assembled Mg-air batteries exhibit specific capacities of up to 1920 mAh g-1 Mg (87.32 % utilization based on the Mg anode). In addition, the resting time of the corresponding Mg-air batteries was 123 times longer than that of Mg-air batteries with pure NaCl electrolytes under the same conditions.

Functional assessments of SARS-CoV-2 single-round infectious particles with variant-specific spike proteins on infectivity, drug sensitivity, and antibody neutralization.

Working with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is restricted to biosafety level III (BSL-3) laboratory. The study used a trans-complementation system consisting of virus-like particles (VLPs) and DNA-launched replicons to generate SARS-CoV-2 single-round infectious particles (SRIPs) with variant-specific spike (S) proteins. S gene of Wuhan-Hu-1 strain (SWH1) or Omicron BA.1 variant (SBA.1), along with the envelope (E) and membrane (M) genes, were cloned into a tricistronic vector, co-expressed in the cells to produce variant-specific S-VLPs. Additionally, the replicon of the WH1-like strain without S, E, M and accessory genes, was engineered under the control by a CMV promoter to produce self-replicating RNAs within VLP-producing cells, led to create SWH1- and SBA.1-based SARS-CoV-2 SRIPs. The SBA.1-based SRIP showed lower virus yield, replication, N protein expression, fusogenicity, and infectivity compared to SWH1-based SRIPs. SBA.1-based SRIP also exhibited intermediate resistance to neutralizing antibodies produced by SWH1-based vaccines, but were effective at infecting cells with low ACE2 expression. Importantly, both S-based SRIPs responded similarly to remdesivir and GC376, with EC50 values ranging from 0.17 to 1.46 µM, respectively. The study demonstrated that this trans-complementation system is a reliable and efficient tool for generating SARS-CoV-2 SRIPs with variant-specific S proteins. SARS-CoV-2 SRIPs, mimicking authentic live viruses, facilitate comprehensive analysis of variant-specific virological characteristics, including antibody neutralization, and drug sensitivity in non-BSL-3 laboratories.

Development of Fluorescence-Tagged SARS-CoV-2 Virus-like Particles by a Tri-Cistronic Vector Expression System for Investigating the Cellular Entry of SARS-CoV-2.

Severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) has caused the pandemic that began late December 2019. The co-expression of SARS-CoV-2 structural proteins in cells could assemble into several types of virus-like particles (VLPs) without a viral RNA genome. VLPs containing S proteins with the structural and functional properties of authentic virions are safe materials to exploit for virus-cell entry and vaccine development. In this study, to generate SARS-CoV-2 VLPs (SCoV2-SEM VLPs) composed of three structural proteins including spike (S), envelop (E) protein and membrane (M) protein, a tri-cistronic vector expression system was established in a cell line co-expressing SARS-CoV-2 S, E and M proteins. The SCoV2-SEM VLPs were harvested from the cultured medium, and three structure proteins were confirmed by Western blot assay. A negative-stain TEM assay demonstrated the size of the SCoV2-SEM VLPs with a diameter of about 90 nm. To further characterize the infectious properties of SCoV2-SEM VLPs, the VLPs (atto647N-SCoV2-SEM VLPs) were fluorescence-labeled by conjugation with atto-647N and visualized under confocal microscopy at a single-particle resolution. The results of the infection assay revealed that atto647N-SCoV2-SEM VLPs attached to the surface of the HEK293T cells at the pre-binding phase in a ACE2-dependent manner. At the post-infection phase, atto647N-SCoV2-SEM VLPs either fused with the cellular membrane or internalized into the cytoplasm with mCherry-rab5-positive early endosomes. Moreover, fusion with the cellular membrane and the internalization with early endosomes could be inhibited by the treatment of camostat (a pharmacological inhibitor of TMPRSS2) and chlorpromazine (an endocytosis inhibitor), respectively. These results elucidated that SCoV2-SEM VLPs behave similarly to the authentic live SARS-CoV-2 virus, suggesting that the development of SCoV2-SEM VLPs provide a realistic and safe experimental model for studying the infectious mechanism of SARS-CoV-2.

Laser-scribed conductive, photoactive transition metal oxide on soft elastomers for Janus on-skin electronics and soft actuators.

Laser-assisted fabrication of conductive materials on flexible substrates has attracted intense interests because of its simplicity, easy customization, and broad applications. However, it remains challenging to achieve laser scribing of conductive materials on tissue-like soft elastomers, which can serve as the basis to construct bioelectronics and soft actuators. Here, we report laser scribing of metallic conductive, photoactive transition metal oxide (molybdenum dioxide) on soft elastomers, coated with molybdenum chloride precursors, under ambient conditions. Laser-scribed molybdenum dioxide (LSM) exhibits high electrical conductivity, biocompatibility, chemical stability, and compatibility with magnetic resonance imaging. In addition, LSM can be made on various substrates (polyimide, glass, and hair), showing high generality. Furthermore, LSM-based Janus on-skin electronics are developed to record information from human skin, human breath, and environments. Taking advantage of its outstanding photothermal effect, LSM-based soft actuators are developed to build light-driven reconfigurable three-dimensional architectures, reshapable airflow sensors, and smart robotic worms with bioelectronic sensors.

Ultra-stable Sb confined into N-doped carbon fibers anodes for high-performance potassium-ion batteries.

Antimony-based materials with high theoretical capacity are known as promising anodes for potassium-ion batteries (PIBs). However, they still face challenges from the large ionic radius of the K ion, which has sluggish kinetics. Much effort is needed to exploit high-performance electrode materials to satisfy the reversible capacity of PIBs. In this paper, nano Sb confined in N-doped carbon fibers (Sb@CN nanofibers) were successfully prepared through an electrospinning method, which was designed to improve potassium storage performances. Sb@CN nanofibers benefit from the fact that the synergy between the porous nanofiber frame structure and the uniformly distributed Sb nano-components in the carbon matrix can effectively accelerate the ion migration rate and reduce the mechanical stress caused by K+ insertion/extraction, Sb@CN nanofiber electrodes thus exhibited excellent potassium storage performance, especially long cycle stability, as expected. When utilized as a PIB anode, they delivered high reversible capacity of 360.2 mAh g-1 after 200 cycles at 50 mA g-1, and a particularly stable capacity of 212.7 mAh g-1 was also obtained after 1000 cycles even at 5000 mA g-1. Given such outstanding electrochemical performances, this work is expected to provide insight into the development and exploration of advanced alloy-type electrodes for PIBs.