Effects of Maleic Anhydride-Grafted Polyethylene on the Properties of Artificial Marble Waste Powder/Linear Low-Density Polyethylene Composites with Ultra-High Filling Content.

The need to reach carbon neutrality as soon as possible has made the use of recycled materials widespread. However, the treatment of artificial marble waste powder (AMWP) containing unsaturated polyester is a very challenging task. This task can be accomplished by converting AMWP into new plastic composites. Such conversion is a cost-effective and eco-friendly way to recycle industrial waste. However, the lack of mechanical strength in composites and the low filling content of AMWP have been major obstacles to its practical application in structural and technical buildings. In this study, a composite of AMWP/linear low-density polyethylene (LLDPE) filled with a 70 wt% AMWP content was fabricated using maleic anhydride-grafted polyethylene as a compatibilizer (MAPE). The mechanical strength of the prepared composites is excellent (tensile strength ~18.45 MPa, impact strength ~51.6 kJ/m2), making them appropriate as useful building materials. Additionally, laser particle size analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermogravimetric analysis were used to examine the effects of maleic anhydride-grafted polyethylene on the mechanical properties of AMWP/LLDPE composites and its mechanism of action. Overall, this study offers a practical method for the low-cost recycling of industrial waste into high-performance composites.

Hierarchical Natural Pollen Cell-Derived Composite Sorbents for Efficient Atmospheric Water Harvesting.

Freshwater scarcity is a critical challenge threatening human survival especially due to poverty and arid and off-grid regions. Sorption-based atmospheric water harvesting (AWH) has emerged as a promising strategy for clean water production. However, most of the high-capacity sorbents are limited by the poor sorption/desorption kinetics and uncontrollable liquid leakage problem. Inspired by the plant transpiration process, we develop an environmentally friendly LiCl@pollen cell-polypyrrole (LiCl@PC-PPy) composite sorbent by confining the LiCl hygroscopic agent in the cages of the PC-PPy. The composite sorbent exhibits much improved sorption/desorption kinetics owing to the hydrophilicity of the hierarchical porous structure of the pollen cells, which provides abundant water sorption active sites and diffusion pathways and forms a concave meniscus on cell skeletons to maximize the thermal utilization efficiency. Moreover, the big cavities of the PC-PPy cages can serve as a water reservoir to reduce liquid leakage. As a result, the sorbent can capture atmospheric water to 85% of its own weight under 60% relative humidity (RH) within 2 h and rapidly release the water within 1 h under weak light irradiation of 0.8 sun. As a proof-of-concept demonstration, the fabricated AWH device can absorb 1.55 gwater/gsorbent at night and collect 1.53 gwater/gsorbent of water in 1-day outdoor operation, and the collected water can meet the drinking water standards defined by the World Health Organization (WHO) and Environmental Protection Agency (EPA).

Enhancing Hydrogen Evolution by Optimizing the Hydrogen Adsorption on Titanium Monoxide Nanodot-Decorated Cobalt Sulfide Nanosheets.

Modulating the local electronic state of metal compounds through interfacial interaction has become a key method for manufacturing high-performance hydrogen evolution reaction (HER) electrocatalysts. The electron-rich active sites can promote the adsorption of hydrogen, which accelerates the Volmer step and thereby enhances the electrocatalytic performance of HER. Here, we found that the strong interfacial interaction between TiO nanodots (TiO/Co-S) and Co-S nanosheets could advantageously improve the performance toward HER of electrocatalyst. Meanwhile, XPS results showed that modulating the local electronic structure of the TiO nanodots produces electron-rich regions on Co. As a result, the overpotential of the TiO/Co-S nanocomposite at 10 mA cm-2 was 107 mV, and the Tafel slope was 83.3 mV dec-1 . This study focused on the effect of the solid-solid interface on the local electronic structure of the catalytic metal active sites and successfully improved the catalytic activity of transition metal materials in HER catalysis.

Glucose photoelectrochemical enzyme sensor based on competitive reaction of ascorbic acid.

A new method based on the competitive reaction of ascorbic acid (AA) was used to improving the performance of photoelectrochemical glucose enzyme sensor. In this method, amplifying the photoelectric signal of H2O2 by the competitive reaction of AA is the key step. The detection can be well operated at 0 V under optimal AA concentration of 10 mM. In the method, AA was regarded as not only the electron donor to capture the hole in the conduction band of ZnO, but also the remover of H2O2 produced by the oxidation of glucose. Both these factors led to the formation of a pair of competitive reactions that enhanced the response towards glucose detection. Compared to the detection without AA, the stability of the response current, detection ranges of 1-19 mM, detection limit of 80 µM and sensitivity of 2.88 µA mM-1·cm-2 were optimized prominently.

Simultaneous Electrochemical Detection of Nitrite and Hydrogen Peroxide Based on 3D Au-rGO/FTO Obtained Through a One-Step Synthesis.

In this paper, Au and reduced graphene oxide (rGO) were successively deposited on fluorine-doped SnO2 transparent conductive glass (FTO, 1 × 2 cm) via a facile and one-step electrodeposition method to form a clean interface and construct a three-dimensional network structure for the simultaneous detection of nitrite and hydrogen peroxide (H2O2). For nitrite detection, 3D Au-rGO/FTO displayed a sensitivity of 419 µA mM-1 cm-2 and a linear range from 0.0299 to 5.74 mM, while for the detection of H2O2, the sensitivity was 236 µA mM-1 cm-2 and a range from 0.179 to 10.5 mM. The combined results from scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction measurements (XRD) and electrochemical tests demonstrated that the properties of 3D Au-rGO/FTO were attributabled to the conductive network consisting of rGO and the good dispersion of Au nanoparticles (AuNPs) which can provide better electrochemical properties than other metal compounds, such as a larger electroactive surface area, more active sites, and a bigger catalytic rate constant.

In situ growth of carbon dots on TiO2 nanotube arrays for PEC enzyme biosensors with visible light response.

Carbon dots (CDs) were grown in situ on secondary anodized TiO2 nanotube arrays (TiO2 NTAs) via a hydrothermal method. The combination of CDs and TiO2 NTAs enhanced the photoelectrochemical performance. Morphology, structure, and elemental composition of the CDs were characterized. No simple physical adsorption was found between the CDs and TiO2, but chemical bonds were formed. UV-vis absorption and fluorescence spectroscopy showed that the CDs could enhance the absorption of TiO2 in the visible and near-infrared regions. Owing to their up-conversion fluorescence properties, the CDs could convert low-energy photon absorption into high-energy photons, which may be used to excite TiO2 to produce a stronger photoelectric response. Moreover, the CDs could effectively transport electrons and accept holes, thus contributing to the effective separation of electrons and holes during photoexcitation. Finally, the PEC biosensor was prepared by immobilizing glucose oxidase (GOx) on the surface of the composite. The PEC biosensor exhibited a broad range of 0.1-18 mM with a detection limit of 0.027 mM under visible irradiation because the composite material reflected strong light absorption for visible light, good conductivity, and good biocompatibility.