High-Performance Hydrogen Evolution Reaction Catalytic Electrodes by Liquid Joule-Heating Growth.

Despite the great progress in the research of integrated catalytic electrodes for hydrogen evolution reaction, the efficient preparation of high-performance catalytic electrodes with high current density remains a challenging issue. In this work, a metal (Pt)-amorphous oxide (NiO) heterostructure catalyst is successfully in situ grown on nickel foam using liquid Joule-heating. Based on the superhydrophilic surface of the electrode and its superior mechanical and chemical stability, the catalytic electrode exhibits excellent catalytic performance in alkaline electrolytes with only 100 mV overpotential to achieve 5000 mA cm-2 current density and maintains a stable performance of 500 h under a fixed current density of 1000 mA cm-2 . Further verification of the practical application of the Pt@NiO-Ni electrode in the alkaline electrolyzer is conducted. The results show that the alkaline water electrolyzer with NiFe layered double hydroxide as the anode and Pt@NiO-Ni as the cathode exhibits superior performance than the previously reported electrolyzers, with a current density of 1 A cm-2 already achieved at 1.75 V, which is even comparable to some anion exchange membrane water electrolyzers. These experimental results illustrate the strong applicability of Pt@NiO-Ni electrode at industrial scale current densities.

Cable-Car Electrocatalysis to Drive Fully Decoupled Water Splitting.

The increasing demand for clean energy conversion and storage has increased interest in hydrogen production via electrolytic water splitting. However, the simultaneous production of hydrogen and oxygen in this process poses a challenge in extracting pure hydrogen without using ionic conducting membranes. Researchers have developed various innovative designs to overcome this issue, but continuous water splitting in separated tanks remains a desirable approach. This study presents a novel, continuous roll-to-roll process that enables fully decoupled hydrogen evaluation reaction (HER) and oxygen evolution reaction (OER) in two separate electrolyte tanks. The system utilizes specially designed "cable-car" electrodes (CCE) that cycle between the HER and OER tanks, resulting in continuous hydrogen production with a purity of over 99.9% and Coulombic efficiency of 98% for prolonged periods. This membrane-free water splitting system offers promising prospects for scaled-up industrial-scale green hydrogen production, as it reduces the cost and complexity of the system, and allows for the use of renewable energy sources to power the electrolysis process, thus reducing the carbon footprint of hydrogen production.

Generalized Rapid Synthesis of Supported Nanocluster Catalyst for Mild Hydrogenation of Phenol toward KA Oil.

Homogeneous and nanometric metal clusters with unique electronic structures are promising for catalysis, however, common synthesis techniques for metal clusters suffer from large size and even metal nanocrystals attributing to their high surface energy and unsaturated configurations. Herein, a generalized rapid annealing strategy for synthesizing a series of supported metal clusters as superior catalysts is developed. Remarkably, TiO2 supported platinum nanoclusters (Pt NC/TiO2 ) exhibits the excellent catalytic activity to realize phenol hydrogenation under mild conditions. The complete phenol conversion rate and 100% selectivity toward KA oil are achieved in aqueous solution at room temperature and normal pressure. Semi-continuous scale up production of KA oil is successfully performed under mild conditions. Such excellent performance mainly originates from the partial reconstruction of Pt NC/TiO2 in aqueous phenol solution. Considering that the phenol can be produced from lignin, this study underpins a facile, sustainable, and economical route to synthesize nylon from biomass.

Soluble Solids Content Binary Classification of Miyagawa Satsuma in Chongming Island Based on Near Infrared Spectroscopy.

Citrus is one of the most important fruits in China. Miyagawa Satsuma, one kind of citrus, is a nutritious agricultural product with regional characteristics of Chongming Island. Near-infrared Spectroscopy (NIR) is a proper method for studying the quality of fruits, because it is low-cost, efficient, non-destructive, and repeatable. Therefore, the NIR technique is used to detect citrus's soluble solid content (SSC) in this study. After obtaining the original spectral data, the first 70% of them are divided into the training set and 30% into the test set. Then, the Random Frog algorithm is chosen to select characteristic wavelengths, which reduces the dimension of the data and the complexity of the model, and accordingly makes the generalization of the classification model better. After comparing the performance of various classifiers (AdaBoost, KNN, LS-SVM, and Bayes) under different characteristic wavelength numbers, the AdaBoost classifier outperforms using 275 characteristic wavelengths for modeling eventually. The accuracy, precision, recall, and F 1-score are 78.3%, 80.5%, 78.3%, and 0.780, respectively and the ROC (Receiver Operating Characteristic Curve, ROC curve) is close to the upper left corner, suggesting that the classification model is acceptable. The results demonstrate that it is feasible to use the NIR technique to estimate whether the citrus is sweet or not. Furthermore, it is beneficial for us to apply the obtained models for identifying the quality of citrus correctly. For fruit traders, the model helps them to determine the growth cycle of citrus more scientifically, improve the level of citrus cultivation and management and the final fruit quality, and thus increase the economic income of fruit traders.

A facile method to synthesize 3D nanosheets of Fe/S dopedα-Ni(OH)2 as an electrocatalyst for improved oxygen evolution reaction.

S-doped Fe/Ni oxide and Fe/Ni hydride oxide catalysts exhibit good oxygen evolution reaction (OER) performance. Nevertheless, the over-doping of S and the agglomeration of active sites still hinder the improvement of the performance of these catalysts. The S/O ratio regulation can optimize the electronic structure effectively so as to improve the OER performance of the catalysts, but few studies have focused on this study. Here, we find a facile room-temperature method to synthesize the unique 3D ultra-thin FeNiOS nanosheets with an adjustable S/O ratio for OER. The FeNiOS-NS catalysts exhibit excellent OER performance with an overpotential of 235 mV at 10 mA cm-2and a small Tafel slope of 64.2 mV dec-1in 0.1 M KOH, which originated from the sufficient exposure of the active Fe-Ni component and the optimized electronic structure due to the tunable S/O ratio. This study demonstrates a novel strategy to optimize the OER performance of Ni-based catalysts.

Ultrafast heating to boost the electrocatalytic activity of iridium towards oxygen evolution reaction.

Efficient electrocatalysts are in great demand for renewable energy storage systems. Herein, we propose an ultrafast heating strategy to fabricate an efficient Ir/CP-UH catalyst for the oxygen evolution reaction (OER). Experimental results demonstrated that the ultrasmall Ir nanoparticles (≈1-3 nm) and clusters (<1 nm) were highly dispersed on the carbon paper support after a short thermal shock (∼5 s). The catalyst showed a low overpotential of 260 mV at 10 mA cm-2 and remarkable mass activity of about 13.8 times higher than that of the current state-of-the-art commercial Ir/C catalyst. This ultrafast heating strategy can also be applied to other catalyst systems for OER and other electrochemical reactions.

Mechanochemical Synthesis of Pt/Nb2CTx MXene Composites for Enhanced Electrocatalytic Hydrogen Evolution.

Production of hydrogen from water splitting has been considered as a promising solution for energy conversion and storage. Since a noble metal-based structure is still the most satisfactory but scarce kind of catalyst, it is significant to allow for practical application of such catalysts by engineering the heterogeneous structure and developing green and facile synthetic strategies. Herein, we report a mechanochemical ball milling synthesis of platinum nanoclusters immobilized on a 2D transition metal carbide MXene (Nb2CTx) as an enhanced catalyst for hydrogen evolution. After annealing at 600 °C, ultrafine Pt3Nb nanoclusters are formed on the Pt/Nb2CTx catalyst. As prepared, the Pt/Nb2CTx-600 catalyst demonstrates superior electrochemical HER activity and stability with an ultralow overpotential of 5 mV and 46 mV to achieve 10 mA cm-2 and 100 mA cm-2, respectively, in comparison with other Nb2CTx-based catalysts and commercial Pt/C catalysts. Moreover, the remarkable durability is also confirmed by accelerated durability tests (ADTs) and long-term chronoamperometry (CA) tests. The excellent HER performance was attributed to high Pt dispersion and more active site exposure by the mechanochemical process and thermal treatment. Such results suggest that the mechanochemical strategy provides a novel approach for rational design and cost-effective production of electrocatalysts, also providing other potential applications in a wide range of areas.

Characterization of a Lytic Bacteriophage against Pseudomonas syringae pv. actinidiae and Its Endolysin.

Pseudomonas syringae pv. actinidiae (Psa) is a phytopathogen that causes canker in kiwifruit. Few conventional control methods are effective against this bacterium. Therefore, alternative approaches, such as phage therapy are warranted. In this study, a lytic bacteriophage (PN09) of Psa was isolated from surface water collected from a river in Hangzhou, China in 2019. Morphologically, PN09 was classified into the Myoviridae family, and could lyse all 29 Psa biovar 3 strains. The optimal temperature and pH ranges for PN09 activity were determined as 25 to 35 ∘C and 6.0 to 9.0, respectively. The complete genome of PN09 was found to be composed of a linear 99,229 bp double-stranded DNA genome with a GC content of 48.16%. The PN09 endolysin (LysPN09) was expressed in vitro and characterized. LysPN09 was predicted to belong to the Muraidase superfamily domain and showed lytic activity against the outer-membrane-permeabilized Psa strains. The lytic activity of LysPN09 was optimal over temperature and pH ranges of 25 to 40 ∘C and 6.0 to 8.0, respectively. When recombinant endolysin LysPN09 was combined with EDTA, Psa strains were effectively damaged. All these characteristics demonstrate that the phage PN09 and its endolysin, LysPN09, are potential candidates for biocontrol of Psa in the kiwifruit industry.

Combined Application of Bacteriophages and Carvacrol in the Control of Pseudomonas syringae pv. actinidiae Planktonic and Biofilm Forms.

Pseudomonas syringae pv. actinidiae (Psa) is the causative agent of the bacterial canker of kiwifruit (Actinidia spp.). Phage therapy has been suggested as a viable alternative approach to controlling this disease, but its efficacy is limited by the emergence of phage-resistant mutants. Carvacrol is an essential oil that may be useful for the control of Psa. Combination therapies can be used to overcome resistance development. Here, the combination of phages (single phage suspensions of phages PN05 and PN09, and a cocktail of both phages) and carvacrol was investigated in controlling Psa planktonic and biofilm forms in vitro. The phage therapy alone (with phages PN05 and PN09), and the carvacrol alone (minimum inhibitory concentration 2.0 mg/mL), inhibited Psa growth, but the combined effect of both therapies was more effective. The phages alone effectively inhibited Psa growth for 24 h, but Psa regrowth was observed after this time. The carvacrol (2.0 mg/mL) alone prevented the biofilm formation for 48 h, but did not destroy the pre-formed biofilms. The combined treatment, phages and carvacrol (2.0 mg/mL), showed a higher efficacy, preventing Psa regrowth for more than 40 h. In conclusion, the combined treatment with phages and carvacrol may be a promising, environment-friendly and cost-effective approach to controlling Psa in the kiwifruit industry.

A miRNA-Encoded Small Peptide, vvi-miPEP171d1, Regulates Adventitious Root Formation.

One of the biggest challenges in clonal propagation of grapevine (Vitis vinifera) is difficulty of rooting. Adventitious root initiation and development are the critical steps in the cutting and layering process of grapevine, but the molecular mechanism of these processes remains unclear. Previous reports have found that microRNA (miRNA)-encoded peptides (miPEPs) can regulate plant root development by increasing the transcription of their corresponding primary miRNA. Here, we report the role of a miPEP in increasing adventitious root formation in grapevine. In this study, we performed a global analysis of miPEPs in grapevine and characterized the function of vvi-miPEP171d1, a functional, small peptide encoded by primary-miR171d. There were three small open reading frames in the 500-bp upstream sequence of pre-miR171d. One of them encoded a small peptide, vvi-miPEP171d1, which could increase the transcription of vvi-MIR171d Exogenous application of vvi-miPEP171d1 to grape tissue culture plantlets promoted adventitious root development by activating the expression of vvi-MIR171d Interestingly, neither exogenous application of the vvi-miPEP171d1 peptide nor overexpression of the vvi-miPEP171d1 coding sequence resulted in phenotypic changes in Arabidopsis (Arabidopsis thaliana). Similarly, application of synthetic ath-miPEP171c, the small peptide encoded by the Arabidopsis ortholog of vvi-MIR171d, inhibited the growth of primary roots and induced the early initiation of lateral and adventitious roots in Arabidopsis, while it had no effect on grape root development. Our findings reveal that miPEP171d1 regulates root development by promoting vvi-MIR171d expression in a species-specific manner, further enriching the theoretical research into miPEPs.

Comparative Analysis of miRNA Abundance Revealed the Function of Vvi-miR828 in Fruit Coloring in Root Restriction Cultivation Grapevine (Vitis vinifera L.).

Root restriction cultivation leads to early maturation and quality improvement, especially in the anthocyanin content in grapevine. However, the molecular mechanisms that underlie these changes have not been thoroughly elucidated. In this study, four small RNA libraries were constructed, which included the green soft stage (GS) and ripe stage (RS) of 'Muscat' (Vitis vinifera L.) grape berries that were grown under root restriction (RR) and in traditional cultivation (no root restriction, CK). A total of 162 known miRNAs and 14 putative novel miRNAs were detected from the four small RNA libraries by high-throughput sequencing. An analysis of differentially expressed miRNAs (DEMs) revealed that 13 miRNAs exhibited significant differences in expression between RR and CK at the GS and RS stages, respectively. For different developmental stages of fruit, 23 and 34 miRNAs showed expression differences between the GS and RS stages in RR and CK, respectively. The expression patterns of the eight DEMs and their targets were verified by qRT-PCR, and the expression profiles of target genes were confirmed to be complementary to the corresponding miRNAs in RR and CK. The function of Vvi-miR828, which showed the down regulated expression in the RS stage under root restriction, was identified by gene transformation in Arabidopsis. The anthocyanin content significantly decreased in transgenic lines, which indicates the regulatory capacity of Vvi-miR828 in fruit coloration. The miRNA expression pattern comparison between RR and CK might provide a means of unraveling the miRNA-mediated molecular process regulating grape berry development under root restricted cultivation.