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Formaldehyde (FA) is widely used in industry and also common in daily life. Finding an efficient method to determine FA is quite an industrial challenge. Herein, a novel method based on a resonance light scattering (RLS) technique was developed for the detection of FA with high sensitivity. Carbon dots (CDs) were used as RLS probes. CDs were obtained via one-pot solvothermal treatment from o-phenylenediamine. CDs showed yellow fluorescence with a quantum yield of 0.41. Due to the multiple amino groups on the surface of CDs, FA can be captured easily by formation of a covalent C = N bond based on the Schiff-base reaction. Owing to the covalent crosslinking, CD nanoparticles aggregated, and even formed precipitate. The aggregation of CDs induced RLS enhancement, where the RLS increment was linearly related to the concentration of FA ranging from 4 nM to 1.6 mM, with a limit of detection (LOD) of 1.6 nM. In comparison with many previous reports, the present RLS method showed a wider linear range and lower LOD. Furthermore, the RLS system was successfully used to detect FA in real food samples. The proposed system has prospective applicability in the detection of FA in food fields.

An octahedral metal-organic framework, MIL-100, was synthesized by a hydrothermal method followed by high-temperature calcination. Thereafter, hematite nanoparticles were assembled on its surface to form Fe2O3-MIL-100, which was used to develop an electrochemical sensor for the sensitive detection of paraquat (PQ). The Fe2O3-MIL-100-based electrochemical sensor showed appreciable sensing performance under optimized conditions, with a linear response in the range of 0.01–30 μM and a limit of detection of 2.6 nM. The Fe2O3-MIL-100-based electrode produced an excellent current response to PQ even after 20 d of storage. Notably, the Fe2O3-MIL-100-based electrochemical sensor exhibited high sensitivity and selectivity for PQ detection in milk and honey samples. Therefore, the fabricated sensor can be an effective tool for the rapid detection of PQ in foods.

Centimeter-scale composite biochar-alginate gel beads (MoS2B/CaCO3/Alg) were designed for the adsorption of Pb(II) in water using MoS2 modified biochar as the filler, alginate as the matrix, and CaCO3 as the active additive component. The composite gel beads were characterized using scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and other techniques. MoS2B/CaCO3/Alg showed excellent adsorption capacity over a wide range of pH 4–7. The maximum adsorption capacities obtained using the Langmuir model were 769.2, 833.3, and 909.1 mg g−1 at 10, 25 and 40 °C, respectively. At a dosing rate of 0.4 g L−1, MoS2B/CaCO3/Alg was able to reduce the Pb(II) concentration to below 0.05 ppm in complex simulated lead battery wastewater. After 10 repeated cycles, MoS2B/CaCO3/Alg maintained a high removal rate of 98.4 %. This spherical adsorbent is simple to prepare and easy to recover, has an ultra-high adsorption capacity, and is mechanically stable and resistant to interference, thus it is expected to be suitable for application in industrial wastewater treatment.

An alginate gel bead composite adsorbent with polyethyleneimine (PEI) as a surface modifier and Eichhornia crassipes (EC) biochar, known as EC-alg/PEI-3, was added internally to the adsorb Cr(VI) from an aqueous environment. The functionalized gel beads were characterized using SEM, XPS, FTIR, and other techniques. The maximum adsorption capacities of EC-alg/PEI-3 were 714.3 mg g−1 at 10 °C and 769.2 mg g−1 at 25 °C. In the treatment of highly concentrated electroplating wastewater, EC-alg/PEI-3 can be dosed at 1.4 g L−1 to reduce the concentration of Cr(VI) to below 0.05 ppm. EC-alg/PEI-3 maintained a competitive adsorption capacity after six cycles. This spherical adsorbent material is easy to prepare, has a very high adsorption capacity, is environmentally friendly, and can be easily recycled. The EC-alg/PEI-3 gel beads are promising for the treatment of industrial wastewater. Errata: Yingnan He, Jianbing Chen, Jiapei Lv, Yimin Huang, Shuxing Zhou, Wenyan Li, Yongtao Li, Fengqin Chang, Hucai Zhang, Thomas Wågberg, Guangzhi Hu, Corrigendum to "Separable amino-functionalized biochar/alginate beads for efficient removal of Cr (VI) from original electroplating wastewater at room temperature". Journal of Cleaner Production, Volume 412, 2023, 137375. DOI: 10.1016/j.jclepro.2023.137375

Fundamental understanding of fabricating promoted bi-functional electrocatalyst to achieve fast charge-transfer and smooth mass-transport in oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) through the rational management of catalyst composition and ingenious design of nanostructure is highly desired but still a formidable challenge. Herein, an advanced carved particle-in-box nanoreactor, composed of small Fe-Co-Ni tri-metallic alloy nanoparticles confined in porous nitrogen-doped carbon nanocage, was developed through a spatially-confined pyrolysis strategy. Tri-metal alloy could optimize the electronic structure of the catalyst, thus inducing the charge redistribution, and then regulating the adsorption and desorption energy barriers of intermediates in electrochemical reactions. Unique nano-hole design provided convenient and efficient channels for mass transfer during ORR and OER processes. Thanks to these attributes, the hybrid electrocatalyst delivered decent reversible oxygen catalytic activities, evidenced by a high half-wave potential of 0.850 V towards ORR and a low overpotential of 355 mV at 10 mA/cm2 for OER both in alkaline electrolyte. As a proof-of-concept, this as-developed carved particle-in-box nanoreactor enabled the assembled Zn-air battery to deliver a narrow potential gap of 0.735 V, a decent power density of 315 mW/cm2, a notable specific capacity of 754 mAh/gZn and excellent durability up to 165 h of continuous charge and discharge operations, thus implying the potential applications of this sophisticated catalyst model for promising energy conversion.

The reduction of nitroaromatics is important in industrial wastewater treatment. However, the activity of an external catalyst is critical for the reaction. In this study, Au nanocrystals were anchored in situ on two-dimensional graphene oxide (GO), which had oxygen-rich groups on its surface. Oxygen-containing groups combined to form functional boron clusters through hydrogen bond interactions (BGO). The mild reducibility of a dodecahydrododecaborate anion cluster (closo-[B12H12]2−) made ultrafine Au nanocrystals uniformly disperse on GO (Au/BGO). 4-Nitrophenol and other nitro-aromatic hydrocarbons could be rapidly hydrogenated into aminoaromatic hydrocarbons by Au/BGO, and the hydrogenation efficiency was approximately 100%. It retained high catalytic activity after 16 catalytic cycles. Therefore, the proposed innovative preparation strategy and high catalytic activity indicate the advancement of closo-[B12H12]2− as a nucleation target for nanometals. This study provides a stable and efficient catalyst for the hydrogenation of nitroaromatics and an alternative approach for the preparation of supported nano-metals. Corrigendum: Yuwen Wang, Xue Zhao, Jianbing Chen, Shuxing Zhou, Xianxi Zhang, Xinzhong Wang, Thomas Wågberg, Guangzhi Hu,Corrigendum to 'Dodecahydrododecaborate anion cluster-reduced nano-Au-decorated graphene oxide for 100% hydrogenation of nitroaromatics', Colloid and Interface Science Communications, 2023, 100713, DOI: 10.1016/j.colcom.2023.100713

Metal‑nitrogen‑carbon materials (M-N-C) have attracted much attention due to their low cost, high abundance, and efficient catalytic performance. Nevertheless, Fe-N-C materials are considered the most promising oxygen reduction reaction (ORR) catalysts for replacing noble metals. Ce is chemically active and has many metal valence states, and empty orbitals that can participate in coordination. On this basis, Fe, Ce-codoped catalyst was constructed in this study. The synergistic effect of the dual metal centers was verified, and a Fe, Ce-codoped nitrogen-doped carbon (FeCeNC) with six equal branch angles was proposed. The half-wave potential for the ORR catalyzed by FeCeNC is 0.855 V. As a rechargeable Zn-air battery cathode catalyst, FeCeNC exhibits excellent electrochemical performances, with an open-circuit voltage of 1.427 V, a maximum power density of 169.2 mW cm−2 and a stable cycling time of 80 h, demonstrating an excellent cycle performance.

Cost-effective and high-performance electrode materials for energy storage and conversion are essential for commercial applications. In this work, the influence of solvent on the morphologies of [CH3NH3][M(HCOO)3] precursors was studied to design and synthesize two-dimensional (2D) porous NiCo2S4 nanosheets with different structures. As an electrode material for supercapacitors, Microflower-NiCo2S4 exhibits excellent capacitance (1,141 F g−1 at 1 A g−1) and stability (88.2% of initial capacitance maintained after 5,000 cycles at 5 A g−1). Moreover, an asymmetric capacitor was constructed using Microflower-NiCo2S4 and porous carbon (PC) and demonstrated an energy density of 51.25 Wh kg−1 at a power density of 397.5 W kg−1. When two Microflower-NiCo2S4//PC asymmetric supercapacitors were assembled in series, the device supplied power for an alarm clock with dimensions of 6.1 × 6.1 cm2 for more than 32 min. Therefore, the preparation of metal sulfides and metal oxides with hollow structures using a [CH3NH3][M(HCOO)3]-template has potential applications in energy storage and conversion.