High Resolution On-Road Air Pollution Using a Large Taxi-Based Mobile Sensor Network.

Traffic-related air pollution (TRAP) was monitored using a mobile sensor network on 125 urban taxis in Shanghai (November 2019/December 2020), which provide real-time patterns of air pollution at high spatial resolution. Each device determined concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), and PM2.5, which characterised spatial and temporal patterns of on-road pollutants. A total of 80% road coverage (motorways, trunk, primary, and secondary roads) required 80-100 taxis, but only 25 on trunk roads. Higher CO concentrations were observed in the urban centre, NO2 higher in motorway concentrations, and PM2.5 lower in the west away from the city centre. During the COVID-19 lockdown, concentrations of CO, NO2, and PM2.5 in Shanghai decreased by 32, 31 and 41%, compared with the previous period. Local contribution related to traffic emissions changed slightly before and after COVID-19 restrictions, while changing background contributions relate to seasonal variation. Mobile networks are a real-time tool for air quality monitoring, with high spatial resolution (~200 m) and robust against the loss of individual devices.

Lithium reduction reaction for interfacial regulation of lithium metal anode.

The lithium metal anode (LMA) is regarded as a very promising candidate for next-generation lithium batteries. The interfacial issue plays a pivotal role in affecting the lithium plating/stripping behavior, Coulombic efficiency and cycling lifespan of an LMA. The lithium reduction reaction (LRR) is an advanced regulating technique for optimizing the LMA interphase, which intelligently utilizes lithium metal itself as an interphase precursor. This strategy also possesses moderate operating conditions, high efficiency, great convenience and scalability. In this review, the latest developments of LRRs in interfacial regulation for LMAs are summarized, focusing on the interfacial regulation mechanism and the construction of various inorganic/organic interfaces in lithium metal liquid/solid batteries. The target interface properties and corresponding influence factors during LRRs are investigated in detail. Besides this, the superiority and insufficiency of LRRs are discussed and possible directions for LRRs are presented. This review highlights in situ modification characteristics for anode interface regulation during the LRR and can be extended to other metal anodes such as sodium, potassium and zinc.

A high-density nickel-cobalt alloy embedded in nitrogen-doped carbon nanosheets for the hydrogen evolution reaction.

The development of novel non-noble electrocatalysts is critical for an efficient electrochemical hydrogen evolution reaction (HER). In this study, high-density nickel-cobalt alloy nanoparticles embedded in the bent nitrogen-doped carbon nanosheets are prepared as a high-performance catalyst. The optimized Ni7Co3/NC-500 catalyst displays quite a low overpotential of 90 mV at a current density of 10 mA cm-2, and a small Tafel slope of 64 mV dec-1 in alkaline medium, and even performs better than commercial 20% Pt/C at a high current density (η150 = 233 mV for Ni7Co3/NC-500 and η150 = 267 mV for 20% Pt/C). Specifically, the high-density nickel-cobalt alloy (with an average size of 6.2 nm and a distance of <3.0 nm) embedded in the bent carbon nanosheets provides plentiful active sites. Furthermore, in situ visualization of the produced hydrogen bubbles shows that the small size of hydrogen bubbles (d = 0.2 mm for Ni7Co3/NC-500 vs. d = 0.8 mm for 20% Pt/C) resulting from the small water contact angle and the bent nanosheet structure would inhibit the aggregation of H2 bubbles on the surface to facilitate efficient mass diffusion. Density functional theory calculations reveal that the formation of the nickel-cobalt alloy can effectively lower water dissociation energy barriers and optimize hydrogen adsorption Gibbs free energy, manifesting a high HER activity.

Lithiophilic Sn-Co nano-seeds sealed in a hollow carbon shell to stabilize lithium metal anodes.

A lithiophilic Sn-Co nano-seed sealed in a nitrogen-doped carbon shell is designed to stabilize lithium metal anodes, in which lithiophilic alloys can regulate lithium deposition behavior and the hollow carbon shell is beneficial to prevent agglomeration. The modified lithium anode can be stable for 1350 h and 400 h under 1 mA cm-2 and 5 mA cm-2 in symmetric cells. The Sn-Co@C@Li||LiFePO4 full cell with a low N/P ratio of 2.12 shows a superior capacity retention of >98% over 250 cycles under 1C.

Plasma-Strengthened Lithiophilicity of Copper Oxide Nanosheet-Decorated Cu Foil for Stable Lithium Metal Anode.

Lithium metal is the most ideal anode for next-generation lithium-ion batteries. However, the formation of lithium dendrites and the continuous consumption of electrolyte during cycling lead to a serious safety problems. Developing stable lithium metal anode with uniform lithium deposition is highly desirable. Herein, a nitrogen plasma strengthening strategy is proposed for copper oxide nanosheet-decorated Cu foil as an advanced current collector, and deep insights into the plasma regulating mechanism are elaborated. The plasma-treated electrode can maintain a high coulombic efficiency of 99.6% for 500 cycles. The symmetric cell using the lithium-plated electrode can be cycled for more than 600 h with a low-voltage hysteresis (23.1 mV), which is much better than those of electrodes without plasma treatment. It is well confirmed that this plasma-induced nitrogen doping method can provide sufficient active sites for lithium nucleation to enhance the stability of lithium deposition on copper oxide nanosheets decorated on Cu foil and improve the electrical conductivity to greatly reduce the overpotential of the lithium nucleation, which can be extended to other modified current collectors for stable lithium metal anode.

Nitrogen Plasma-Treated Core-Bishell Si@SiOx@TiO2-δ: Nanoparticles with Significantly Improved Lithium Storage Performance.

Si-based anode materials have attracted considerable attention because of their ultrahigh reversible capacity. However, poor cycling stability caused by the large volume change during cycling prevented the commercial application of Si anodes for lithium-ion batteries (LIBs). To overcome these challenges, in the present study, we designed a nitrogen plasma-treated core-bishell nanostructure where the Si nanoparticle was encapsulated into a SiOx shell and N-doped TiO2-δ shell. Here, the SiOx inside the shell and the TiO2 outside the shell act as binary buffer matrices to accommodate the large volume change and also help to stabilize the solid electrolyte interphase films on the shell surface. More importantly, the plasma-induced N-doped TiO2-δ shell with many Ti3+ species and oxygen vacancies plays a key role in improving the electrical conductivity of Si anodes. Owing to the synergistic effects of SiOx and N-doped TiO2-δ bishells, the cycling stability and rate performance of Si anodes are significantly enhanced. The as-obtained sample exhibits superior cycling stability with a capacity retention of 650 mA h g-1 at 200 mA g-1 after 300 cycles. This strategy is favorable for improving the electrochemical performances of Si-based anodes to employ in practical LIBs.

Synergistically enhanced oxygen reduction activity of MnO(x)-CeO2/Ketjenblack composites.

Here we report a hybrid of MnOx-CeO2/Ketjenblack as a novel catalyst for oxygen reduction reaction (ORR) by a facile strategy. This hybrid exhibits comparable activity and better stability towards ORR than the commercial 20 wt% Pt/C due to the synergistic effect.

Irradiation-mediated carbon nanotubes' use in cancer therapy.

Anticancer drugs such as biological therapeutic proteins and peptides are used for treatment of a variety of tumors. However, their wider use has been hindered by their poor bioavailability and the uncontrollable sites of action in vivo. Cancer nano-therapeutics is rapidly progressing, which is being applied for solving some limitations of conventional drug delivery systems. To improve the bio-distribution of anticancer drugs, carbon nanotubes have been used as one of the most effective drug carriers. This review discusses the carbon nanotubes-mediated methods for the delivery of anticancer drugs, with emphasis on the radiation-induced drug-targeted releasing and selective photo-thermal cancer therapy.