One-Dimensional CoMoP Nanostructures as Bifunctional Electrodes for Overall Water Splitting

As high-quality substitutes for conventional catalysts, the bifunctional catalytic properties of the coating of transition-metal-based materials are pivotal for improving water-splitting efficiency. Herein, cobalt-molybdenum bimetallic phosphide nanofibers (CoMoP NFs) were synthesized via a series of facile strategies, which are divided into pyrolysis electrospun PAN and metal salts, to obtain one-dimensional morphology and a gas-solid phosphating precursor. The obtained CoMoP NFs catalyst has superior catalytic activity performance in 1M KOH. Serving as an oxygen evolution reaction (OER) catalyst, the electrode of the CoMoP NFs affords different kinds of current densities at 50 mA cm−2 and 100 mA cm−2, with low overpotentials of 362 and 391 mV, respectively. In addition, the hydrogen evolution reaction (HER) performance of the CoMoP NFs mainly shows when under a low overpotential of 126 mV, which can deliver a current density of 10 mA cm−2. In order to further detect the stability of the catalyst, we used multiple cyclic voltammetry and chronopotentiometry tests for OERs and HERs, which maintain performance and carry a current density of 10 mA cm−2 for longer. As an integrated high-performance bifunctional electrode for overall water splitting, the CoMoP NFs only require 1.75 V@10 mA cm−2 for 40 h. This work highlights a facile method to create an electrocatalyst with fiber nanostructures which possesses excellent activity as an alkaline electrolyte

Regionalized multiple-point stochastic geological modeling: A case from braided delta sedimentary reservoirs in Qaidam Basin, NW China

Research on the depositional model of a braided delta in Kunbei oilfield, Qaidam Basin, was conducted with a fine geologic study in a dense well network area by combining sedimentary physical simulation to obtain statistical characteristic parameters and allocation relations of plane sedimentary facies units. On this basis, training images in different sedimentary regions of the braided delta were developed for reservoir modeling. In each sub-region, sequential conditional simulation in adjacent regions used different training images with angle revolving and scaling. This simulation succeeded in finely modeling the sedimentary microfacies of the braided delta. This method relaxed the requirement for a stationary training image in multipoint simulation and improved channel continuity as well as portability of the training image. In the fine reservoir description of the Kunbei oilfield, the model results were consistent with practical production and have the potential to guide effective water-flooding development. Effective application demonstrated the feasibility and practicability of the method. This paper presents a new method for accurately characterizing the braided delta using stochastic simulation. Key words: regionalized multi-point statistics, stochastic geological modeling, training image, sedimentary microfacies, braided delta, Qaidam Basi

Three-Dimensional Mesoporous Covalent Organic Frameworks through Steric Hindrance Engineering

International audienceThe development of three-dimensional covalent organic frameworks (COFs) with large pores and high surface areas is of great importance for various applications. However, it remains a major challenge due to the unavoidable structural interpenetration and pore collapse after the removal of guest species sitiated in the pores. Herein, we report for the first time a series of 3D mesoporous COFs through a general strategy of enhanced steric hindrance. By using methoxy-modified monomer and increasing methyl groups of linkers, these 3D COFs can be obtained successfully as exclusively non-interpenetrated diamondoid structures, permanent mesopores (up to 26.5 Å), and high surface areas (> 3000 m 2 g-1), which are far superior to those of reported conventional COFs with the same topology. This work thus opens a way to create 3D large-porous COFs for potential applications in adsorption and separation of large inorganic, organic, and biological species

Ambient aqueous-phase synthesis of covalent organic frameworks for degradation of organic pollutants

International audienc

Design and Synthesis of a Zeolitic Organic Framework

The development of three-dimensional (3D) architectures in COFs has been considered important owing to their prospective ad-vantages in high surface areas and plentiful active sites. Herein, we report the first example of a 3D COF with zeolitic network, namely the zeolitic organic framework (ZOF). By combining two kinds of tetrahedral building blocks with fixed or relatively free bond angles, ZOF-1 with the zeolitic crb net has been successfully synthesized. Its structure was determined by the single-crystal 3D electron dif-fraction technique. Remarkably, ZOF-1 shows high chemical stabil-ity, large pore size (up to 16 Å), and excellent specific surface area (~ 2785 m2/g), which is superior to its analogues with the same network, including traditional aluminosilicate zeolites and zeolitic imidazole frameworks. This study thus opens a new avenue to construct 3D COFs with zeolitic topologies and promotes the struc-tural diversity and practical applications of COF materials

Design and Synthesis of a Zeolitic Organic Framework

International audienceThe development of novel zeolite-like materials with large channel windows and high stability is of importance but remains a tremendous challenge. Herein, we report the first example of a 3D covalent organic framework with zeolitic network, namely the zeolitic organic framework (ZOF). By combining two kinds of tetrahedral building blocks with fixed or relatively free bond angles, ZOF-1 with the zeolitic crb net has been successfully synthesized. Its structure was determined by the single-crystal 3D electron diffraction technique. Remarkably, ZOF-1 shows high chemical stability, large pore size (up to 16 Å), and excellent specific surface area (~ 2785 m2/g), which is superior to its analogues with the same network, including traditional aluminosilicate zeolites and zeolitic imidazole frameworks. This study thus opens a new avenue to construct zeolite-like materials with pure organic frameworks and will promote their potential applications in adsorption and catalysis for macromolecules

Multiscale understanding of electric polarization in poly(vinylidene fluoride)-based ferroelectric polymers

From Crossref journal articles via Jisc Publications RouterArticle version: VoRFunder: China Scholarship Council; FundRef: 10.13039/501100004543; Grant(s): 201606280030, 201506630005Funder: Engineering and Physical Sciences Research Council; FundRef: 10.13039/501100000266; Grant(s): EP/L017695/1Funder: National Natural Science Foundation of China; FundRef: 10.13039/501100001809; Grant(s): 52073046The electric polarization of ferroelectric polymers with tailored structures was studied using the terahertz time-domain spectroscopy technique combined with impedance analysis