Hollow Carbon Nanopillar Arrays Encapsulated with Pd–Cu Alloy Nanoparticles for the Oxygen Evolution Reaction

Delicate design and bottom-up synthesis of hollow nanostructures for oxygen evolution electrocatalysts is a promising way to accelerate the reaction kinetics of overall water splitting. Herein, an efficient and versatile strategy for the controllable preparation of Pd–Cu alloy nanoparticles encapsulated in carbon nanopillar arrays (PD–Cu@HPCN) is developed. Core–shell structured MOF@imidazolium-based ionic polymers (ImIPs) have been prepared and adopted as a template, along with the decomposition of the inner Cu–MOFs when an anion exchange occurs between sodium tetrachloropalladate in solution and bromides in the external ImIP shell. Pd nanoparticles will be highly dispersed in the resulting Pd–Cu@HO-ImIP array, and subsequent topotactic transformation generates Pd–Cu@HNPC. No hazardous reagents or tedious steps are used to remove the inner Cu–MOF templates in contrast to the traditional top-down methods. Remarkably, the Pd–Cu@HPCN catalyst possesses outstanding oxygen evolution reaction (OER) activity, including small overpotential with 10 mA cm–2 at an overpotential of 188 mV, a large double layer capacitance (73.8 mF cm–2), and high stability (20 h). This simple, green, and efficient synthesis methodology represents a new way to design metal alloys for OER electrocatalysts or other electrocatalytic devices

<i>In Situ</i>-Generated Hollow CoFe-LDH/Co-MOF Heterostructure Nanorod Arrays for Oxygen Evolution Reaction

Assembling a heterostructure is an effective strategy for enhancing the electrocatalytic activity of hybrid materials. Herein, CoFe-layered double hydroxide and Co-metal–organic framework (CoFe-LDH/Co-MOF) hollow heterostructure nanorod arrays are synthesized. First, [Co(DIPL)(H3BTC)(H2O)2]n [named as Co-MOF, DIPL = 2,6-di(pyrid-4-yl)-4-phenylpyridine, H3BTC = 1,3,5-benzenetricarboxylic acid] crystalline materials with a uniform hollow structure were prepared on the nickel foam. The CoFe-LDH/Co-MOF composite perfectly inherits the original hollow nanorod array morphology after the subsequent electrodeposition process. Optimized CoFe-LDH/Co-MOF hollow heterostructure nanorod arrays display excellent performance in oxygen evolution reaction (OER) with ultralow overpotentials of 215 mV to deliver current densities of 10 mA cm–2 and maintain the electrocatalytic activity for a duration as long as 220 h, ranking it one of the non-noble metal-based electrocatalysts for OER. Density functional theory calculations validate the reduction in free energy for the rate-determining step by the synergistic effect of Co-MOF and CoFe-LDH, with the increased charge density and noticeable electron transfer at the Co–O site, which highlights the capability of Co-MOF to finely adjust the electronic structure and facilitate the creation of active sites. This work establishes an experimental and theoretical basis for promoting efficient water splitting through the design of heterostructures in catalysts

Image1_Genome-wide Identification and Evolution of the PP2C Gene Family in Eight Rosaceae Species and Expression Analysis Under Stress in Pyrus bretschneideri.TIF

Type 2C protein phosphatase (PP2C) plays an essential role in abscisic acid (ABA) signaling transduction processes. In the current study, we identify 719 putative PP2C genes in eight Rosaceae species, including 118 in Chinese white pear, 110 in European pear, 73 in Japanese apricot, 128 in apple, 74 in peach, 65 in strawberry, 78 in sweet cherry, and 73 in black raspberry. Further, the phylogenetic analysis categorized PbrPP2C genes of Chinese white pear into twelve subgroups based on the phylogenic analysis. We observed that whole-genome duplication (WGD) and dispersed gene duplication (DSD) have expanded the Rosaceae PP2C family despite simultaneous purifying selection. Expression analysis finds that PbrPP2C genes have organ-specific functions. QRT-PCR validation of nine PbrPP2C genes of subgroup A indicates a role in ABA-mediated response to abiotic stress. Finally, we find that five PbrPP2C genes of subgroup A function in the nucleus. In summary, our research suggests that the PP2C family functions to modulate ABA signals and responds to abiotic stress.</p

DataSheet1_Genome-wide Identification and Evolution of the PP2C Gene Family in Eight Rosaceae Species and Expression Analysis Under Stress in Pyrus bretschneideri.xlsx

Type 2C protein phosphatase (PP2C) plays an essential role in abscisic acid (ABA) signaling transduction processes. In the current study, we identify 719 putative PP2C genes in eight Rosaceae species, including 118 in Chinese white pear, 110 in European pear, 73 in Japanese apricot, 128 in apple, 74 in peach, 65 in strawberry, 78 in sweet cherry, and 73 in black raspberry. Further, the phylogenetic analysis categorized PbrPP2C genes of Chinese white pear into twelve subgroups based on the phylogenic analysis. We observed that whole-genome duplication (WGD) and dispersed gene duplication (DSD) have expanded the Rosaceae PP2C family despite simultaneous purifying selection. Expression analysis finds that PbrPP2C genes have organ-specific functions. QRT-PCR validation of nine PbrPP2C genes of subgroup A indicates a role in ABA-mediated response to abiotic stress. Finally, we find that five PbrPP2C genes of subgroup A function in the nucleus. In summary, our research suggests that the PP2C family functions to modulate ABA signals and responds to abiotic stress.</p

Additional file 4 of Genome-wide identification and comparative analysis of the PYL gene family in eight Rosaceae species and expression analysis of seeds germination in pear

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Additional file 3 of Genome-wide identification and comparative analysis of the PYL gene family in eight Rosaceae species and expression analysis of seeds germination in pear

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Additional file 1 of Genome-wide identification and comparative analysis of the PYL gene family in eight Rosaceae species and expression analysis of seeds germination in pear

Additional file 1

Table_1_Chemical Composition and Crystal Morphology of Epicuticular Wax in Mature Fruits of 35 Pear (Pyrus spp.) Cultivars.XLSX

<p>An evaluation of fruit wax components will provide us with valuable information for pear breeding and enhancing fruit quality. Here, we dissected the epicuticular wax concentration, composition and structure of mature fruits from 35 pear cultivars belonging to five different species and hybrid interspecies. A total of 146 epicuticular wax compounds were detected, and the wax composition and concentration varied dramatically among species, with the highest level of 1.53 mg/cm² in Pyrus communis and the lowest level of 0.62 mg/cm² in Pyrus pyrifolia. Field emission scanning electron microscopy (FESEM) analysis showed amorphous structures of the epicuticular wax crystals of different pear cultivars. Cluster analysis revealed that the Pyrus bretschneideri cultivars were grouped much closer to Pyrus pyrifolia and Pyrus ussuriensis, and the Pyrus sinkiangensis cultivars were clustered into a distant group. Based on the principal component analysis (PCA), the cultivars could be divided into three groups and five groups according to seven main classes of epicuticular wax compounds and 146 wax compounds, respectively.</p

Additional file 6 of Genome-wide identification and comparative analysis of the PYL gene family in eight Rosaceae species and expression analysis of seeds germination in pear

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Additional file 2 of Genome-wide identification and comparative analysis of the PYL gene family in eight Rosaceae species and expression analysis of seeds germination in pear

Additional file 2