Multi-Functional Formaldehyde-Nitrate Batteries for Wastewater Refining, Electricity Generation, and Production of Ammonia and Formate.

As bulky pollutants in industrial and agricultural wastewater, nitrate and formaldehyde pose serious threats to the human health and ecosystem. Current purification technologies including chemical and bio-/photo-/electro-chemical methods, are generally high-cost, time-consuming, or energy-intensive. Here, we report a novel formaldehyde-nitrate battery by pairing anodic formaldehyde oxidation with cathodic nitrate reduction, which simultaneously enables wastewater purification, electricity generation, and the production of high-value-added ammonia and formate. As a result, the formaldehyde-nitrate battery remarkably exhibits an open-circuit voltage of 0.75 V, a peak power density of 3.38 mW cm-2 and the yield rates of 32.7 mg h-1 cm-2 for ammonia and 889.4 mg h-1 cm-2 for formate. In a large-scale formaldehyde-nitrate battery (25 cm2 ), 99.9 % of nitrate and 99.8 % of formaldehyde are removed from simulated industrial wastewater and the electricity of 2.03 W⋅h per day is generated. Moreover, the design of such a multi-functional battery is universally applicable to the coupling of NO3 - or NO2 - reduction with various aldehyde oxidization, paving a new avenue for wastewater purification and chemical manufacturing.

Functional Aqueous Zinc-Acetylene Batteries for Electricity Generation and Electrochemical Acetylene Reduction to Ethylene.

The available processes for removing acetylene impurities from crude ethylene are tremendously energy-intensive. Herein, we demonstrate a novel aqueous Zn-C2 H2 battery, which not only switches energy-consuming acetylene removal to electricity generation, but also reduces acetylene to ethylene through a unique discharge mechanism: C2 H2 +Zn+H2 O→C2 H4 +ZnO. Under a pure acetylene stream, this Zn-C2 H2 battery exhibits an open circuit potential of 1.14 V and a peak power density of 2.2 mW cm-2 , which exceed those of reported Zn-CO2 batteries. Even for simulated crude ethylene, the Zn-C2 H2 battery manifests an acetylene conversion of 99.97 % and continuously produces polymer-grade ethylene with only ≈3 ppm acetylene during a long-term discharge operation. Such a functional battery is universally appliable for reducing other alkynes and generating electricity. Therefore, this work provides an effective strategy for green ethylene purification and the design of functional batteries.

Deprotonated 2-thiolimidazole serves as a metal-free electrocatalyst for selective acetylene hydrogenation.

Metal-free catalysts offer a desirable alternative to traditional metal-based electrocatalysts. However, metal-free catalysts, featuring defined active sites, rarely show activities as promising as metal-based materials. Here we report 2-thiolimidazole as an efficient metal-free catalyst for selective electrocatalytic hydrogenation of acetylene into ethylene. Under alkaline conditions, the sulfhydryl and imino groups of 2-thiolimidazole are spontaneously deprotonated into dianions. Deprotonation thus enriches the negative charges of pyridinic N sites in 2-thiolimidazole to enhance the adsorption of electrophilic acetylene through the σ-configuration. Ethylene partial current densities show a volcano relationship with the negative charges of the pyridinic N sites in various imidazole derivatives. Consequently, the deprotonated 2-thiolimidazole exhibits an ethylene partial current density and faradaic efficiency competitive with metal-based catalysts like Cu and Pd. This work highlights the tunability and promising potential of metal-free molecules in electrocatalysis.

Protein-polysaccharides based nanoparticles for loading with Malus baccata polyphenols and their digestibility in vitro.

The poor solubility, instability and low absorption rate obstruct the bioavailability of polyphenols isolated from Malus baccata (MBP) during gastrointestinal digestion. In order to solve the limitable problems, the food-grade nanoparticles were fabricated by mucin (MC) and Hohenbuehelia serotina polysaccharides (HSP) for delivery of MBP (MBP-NPs). The physicochemical properties and morphology of MBP-NPs prepared by different condition were respectively characterized. During gastrointestinal digestion in vitro, the release characteristic and variation in phenolic composition of MBP-NPs were evaluated. The results showed that MBP-NPs formed by hydrogen bonding and hydrophobic interaction possessed the regularly spherical shapes and smooth surfaces and semi-crystalline properties. Moreover, MBP-NPs presented the excellent physicochemical stability. During simulated gastrointestinal digestion in vitro, MBP-NPs exhibited the sustained release characteristics of phenolic compounds, which were confirmed by SDS-PAGE measurement. Compared with that of unencapsulated MBP, the significant variation was occurred in the phenolic composition of MBP-NPs, indicating that MBP-NPs could prevent the degradation and transformation of phenolic compounds. This study provides a novel strategy to improve the bioavailability of polyphenols.

Polysaccharides from the hard shells of Juglans regia L. modulate intestinal function and gut microbiota in vivo.

This study aimed to investigate the modulatory effects of polysaccharides from the hard shells ofJuglans regiaL. (JRP) on intestinal function and gut microbiota of mice. The results showed that JRP could increase the colonic length and colonic index, and ameliorate the histological characteristics of colon. JRP had a positive effect on immunity of mice by improving immune organ indexes. Owing to enhancement of intestinal peristalsis and increase of colonic fecal moisture by JRP, the defecation time was significantly reduced. After gastrointestinal digestion and absorption, JRP was metabolized by intestinal microorganisms to produce short chain fatty acids, thereby lowering the pH of intestine. Through microbial community analysis, the composition of gut microbiota was modulated by JRPvia increasing theabundances of beneficial bacteriaand decreasing the richness of harmful bacteria. This study suggests that JRP can be served as an excellent prebiotic to promote intestinal health.

Malus baccata (Linn.) Borkh polyphenols-loaded nanoparticles ameliorate intestinal health by modulating intestinal function and gut microbiota.

The aim of this study was to construct the nanoparticles based on Hohenbuehelia serotina polysaccharides and mucin for encapsulation of the polyphenols from Malus baccata (Linn.) Borkh (MBP-MC-HSP NPs), and investigate their effects on intestinal function and gut microbiota in mice. The results showed that MBP-MC-HSP NPs did not have any toxic and side effect by determining organ indexes and hematological parameters. The colonic index, colonic length as well as colonic histology were significantly improved by treatment of MBP-MC-HSP NPs. Moreover, MBP-MC-HSP NPs could increase the fecal moisture (84.71 %) and accelerate the intestinal peristalsis (77.87 %), thus reducing the defecation time (1.68 h) of mice at certain extent. Through production of acetic acid, propionic acid and n-butyric acid, MBP-MC-HSP NPs remarkably decreased the pH of colonic feces to maintain intestinal health. 16S rRNA sequencing analysis showed that MBP-MC-HSP NPs could improve the abundances of Lactobacillus, Butyicicoccus and Ruminococcus and suppress the richness of Prevotella, Bifidobacterium and Desulfovibrio, thereby optimizing the structure and composition of gut microbiota. Furthermore, the metabolic profiles of gut microbiota were influenced by MBP-MC-HSP NPs based on prediction of KEGG and COG databases. Overall, this study suggests that MBP-MC-HSP NPs can be developed and utilized as probiotics in the nutritional food field.

Highly selective electrocatalytic alkynol semi-hydrogenation for continuous production of alkenols.

Alkynols semi-hydrogenation is a critical industrial process as the product, alkenols, have extensive applications in chemistry and life sciences. However, this class of reactions is plagued by the use of high-pressure hydrogen, Pd-based catalysts, and low efficiency of the contemporary thermocatalytic process. Here, we report an electrocatalytic approach for selectively hydrogenating alkynols to alkenols under ambient conditions. For representative 2-methyl-3-butene-2-ol, Cu nanoarrays derived electrochemically from CuO, achieve a high partial current density of 750 mA cm-2 and specific selectivity of 97% at -0.88 V vs. reversible hydrogen electrode in alkaline solution. Even in a large two-electrode flow electrolyser, the Cu nanoarrays deliver a single-pass alkynol conversion of 93% with continuous production of 2-methyl-3-butene-2-ol at a rate of ~169 g gCu-1 h-1. Theoretical and in situ electrochemical infrared investigations reveal that the semi-hydrogenation performance is enhanced by exothermic alkynol adsorption and alkenol desorption on the Cu surfaces. Furthermore, this electrocatalytic semi-hydrogenation strategy is shown to be applicable to a variety of alkynol substrates.

Co-Ni layered double hydroxides wrapped on leaf-shaped copper oxide hybrids for non-enzymatic detection of glucose.

The leaf-shaped copper oxide (CuO) was first fabricated by a direct precipitation method. Then, the flake-shaped Co-Ni layered double hydroxides (CoNi-LDHs) were grown on the leaf-shaped CuO by using an electrodeposition method to form a unique nanostructured electrocatalyst. Due to the unique structural and compositional advantages, CoNi-LDHs wrapped around the leaf-shaped CuO exhibited good electrocatalytic characteristics. The optimized CuO/CoNi-LDHs exhibited improved non-enzymatic electrochemical sensing performance for glucose, with a reliable linear range (0.1 µM-0.384 mM) and a low limit of detection (0.065 µM, S/N = 3). The utilization of the CuO/CoNi-LDHs sensor for glucose detection in human serum was also corroborated, implying promising potential for glucose monitoring. Results demonstrated that the developed sensor provides new horizons for facile and sensitive glucose detection.

Construction and characterization of Juglans regia L. polyphenols nanoparticles based on bovine serum albumin and Hohenbuehelia serotina polysaccharides, and their gastrointestinal digestion and colonic fermentation in vitro.

Herein, we report the construction and characterization of nanoparticles based on bovine serum albumin and Hohenbuehelia serotina polysaccharides for the delivery of polyphenols isolated from the shells of Juglans regia L. (BSA-JRP-HSP NPs). We also systematically investigated their gastrointestinal digestion and colonic fermentation characteristics in vitro. BSA-JRP-HSP NPs, with amorphous properties and regular spherical morphological features, have a high encapsulation efficiency of 88.47 ± 0.04%, average particle size of 285.7 ± 3.1 nm, and zeta potential of -12.20 ± 0.61 mV, and they exhibit excellent photothermal stabilities and strong mucin adhesion capacity. Through measurements of gastrointestinal digestion and colonic fermentation in vitro, the results suggest that BSA-JRP-HSP NPs presented well-sustained release characteristics for preventing the biodegradation of JRP during gastrointestinal digestion. After gastrointestinal digestion, BSA-JRP-HSP NPs could modulate the composition and structure of gut microbiota, promoting the growth of beneficial bacterial (e.g. Prevotella, Dialister, Akkermansia, etc.) and inhibiting the growth of pathogenic bacteria (e.g. Bacteroides, Phascolarctobacterium, Lachnospiracea incertae sedis, etc.). The production of short-chain fatty acids (SCFAs) including acetic acid, propionic acid, and butyric acid was remarkably enhanced by treatment with BSA-JRP-HSP NPs. This study has proved that BSA-JRP-HSP NPs can serve as a novel candidate for improving the bioavailability of JRP.

Construction of Hohenbuehelia serotina polysaccharides-mucin nanoparticles and their sustain-release characteristics under simulated gastrointestinal digestion in vitro.

In this study, Hohenbuehelia serotina polysaccharides-mucin nanoparticles (HSP-MC NPs) were fabricated based on hydrogen bonding and hydrophobicity effects for improving the bioavailability of HSP. The structural characteristics and morphology of HSP-MC NPs prepared by different conditions were respectively identified and observed. The results showed that HSP-MC NPs (HSP/MC, 1/1, w/w) presented the optimal physicochemical characteristics, with the encapsulation efficiency of 88.09 ± 0.01%, average particle size of 509.4 ± 9.76 nm and zeta potential of -20.6 ± 0.7 mV. Furthermore, HSP-MC NPs (HSP/MC, 1/1, w/w), belonged to non-crystalline substances, exhibited the excellent physicochemical stabilities against temperature, pH and ionic strength, and had the uniform spherical morphological characteristics. In addition, under simulated gastrointestinal digestion in vitro, HSP-MC NPs (HSP/MC, 1/1, w/w) showed the good sustained release performances, that might effectively improve the absorption rate of HSP. The present research is meaningful for designing the polysaccharides-loaded nano-delivery system based on natural non-toxic carrier that can be used in function food field.

Preparation of Pt anchored on cerium oxide and ordered mesoporous carbon tri-component composite for electrocatalytic oxidation of adrenaline.

The preparation of Pt/cerium oxide and highly ordered mesoporous carbon (Pt/CeO2/OMC) nanohybrids is reported. CeO2 can be used as an active material that enhances the electrocatalytic properties of Pt nanoparticles. OMC exhibits excellent electrical conductivity and large specific surface area, which makes it a highly promising electrocatalyst support. Benefiting from the synergistic effects of the catalytic performance of Pt/CeO2 and excellent conductivity of OMC supports, the new nanocomposite of Pt/CeO2/OMC are able to create novel features of electrocatalytic activities. Pt/CeO2/OMC tri-component composite was used as an excellent sensing platform for the determination of adrenaline. The developed sensor exhibited excellent activity and convincing analytical performance towards adrenaline, such as wide linear range, high sensitivity, low limit of detection, and low limit of quantification. In addition, the recoveries ranging from 93.4 to 103.6% were obtained in human serum samples. The successful preparation of Pt/CeO2/OMC tri-component composite may promote the development of novel electrocatalyst and facilitate the design of new electrochemical sensors.

A novel cobalt and nitrogen co-doped mesoporous hollow carbon hemisphere as high-efficient electrocatalysts for oxygen reduction reaction.

Exploring a cheap catalyst with effective activity for oxygen reduction reaction (ORR) to replace precious metal electrocatalysts has gained tremendous attention for several decades. In this study, we designed and synthesized cobalt and nitrogen supported on mesoporous hollow carbon hemisphere (Co/N/HCHs) nanocomposites by a facile and economical approach. Semisphere-shaped mesoporous hollow carbon is self-generated using silica particles as template, followed by a pyrolysis-etching process; and exhibits high electrical conductivity and high specific surface. The unique porous structure of carbon provides significant number of the abundant defective sites and shortens the mass transfer pathway, leading to a greatly enhanced electrocatalytic activity with mainly 4e- reduction. Moreover, the synergistic effects of large electrochemically active areas and good electrical conductivity, resulting from the introduction of Co and N heteroatom, are the main reason for displaying outstanding ORR activity with a high half-wave potential of 0.8 V and the electron transfer numbers of 3.89. Furthermore, an excellent long-term stability (the current density retention of 87.0%) and superb methanol tolerance in alkaline medium are achieved. Undoubtedly, this demonstrates a potential way to strategically design the non-precious metal doped carbon catalysts for wider practical applications.

Facile synthesis of Fe, Co bimetal embedded nanoporous carbon polyhedron composites for an efficient oxygen evolution reaction.

The development of highly efficient, stable, and low-cost non-noble-metal electrocatalysts for oxygen evolution reactions (OER) is a major challenge for facilitate the efficiency of green energy storage. Bimetallic oxides are considered promising candidates as the electrocatalysts for OER because of their remarkable electrocatalytic activity, good stability, and low cost. In this work, ZIF-67 precursors were prepared via microwave irradiation and used as a self-sacrificing template. We proposed a rapid and scalable strategy to prepare Fe, Co bimetal embedded nanoporous carbon (Fe-Co/NPC) polyhedron composites by thermal decomposition of Fe species incorporated ZIF-67 precursor. Benefiting from the distinctive 3D polyhedron structural and compositional advantages, Fe-Co/NPC with hierarchical porous structure showed excellent electrochemical performance as ideal electrode material for OER. The resulting Fe-Co/NPC displayed outstanding electrocatalytic activity for OER with appreciable onset potential (1.59 V (vs. RHE)), small Tafel slope (53.55 mV dec-1), low over-potential (396 mV) to reach 10 mA cm-2, and excellent durability with negligible loss in current density after 1000 cycles. The current work demonstrated new insight into the design and construction of 3D structured Fe-Co/NPC polyhedron catalysts with highly electrocatalytic activity and good stability for electrocatalysis applications.

An enzyme-free electrochemical biosensor based on well monodisperse Au nanorods for ultra-sensitive detection of telomerase activity.

Efficient platforms for detecting telomerase activity are essential for early tumor monitoring and diagnosis. Herein, an enzyme-free electroanalytical strategy was developed for reliable and highly sensitive telomerase activity assay based on the increased electrochemical signals of methylene blue (MB) catalyzed by well monodisperse Au nanorods (AuNRs). In the presence of dNTPs and telomerase extracts, the assistant DNA 1 in the double stranded DNA can be extended to telomere repeat units (TTAGGG)n, which could form a hairpin structure by telomerase-triggered extension. The assistant DNA 2 was ingeniously dissociated from the double stranded DNA to combine with capture DNA. As a result, a large amount of AuNRs could be anchored on the surface of these sequences and used for electrocatalytic oxidation of MB. The developed biosensor showed a low limit of detection of 8.20 HeLa cells mL-1 and a wide dynamic range from 30 to 1.04 × 107 HeLa cells mL-1 for the determination of telomerase activity, which can provide a new way for telomerase activity assays in early diagnosis for cancers.