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Coupling effect of chemical composition and physical structure is a key factor to construct superaerophobic electrodes. Almost all reports about superaerophobic electrodes were aimed at precisely controlling morphology of loaded materials (constructing specific structure) and ignored the due role of substrate. Nevertheless, in this work, by using high precision and controllable femtosecond laser, hierarchical micro-nano structures with superaerophobic properties were constructed on the surface of silicon substrate (fs-Si), and such special super-wettability could be successfully inherited to subsequent self-supporting electrodes through chemical synthesis. Femtosecond laser processing endowed electrodes with high electrochemical surface area, strong physical structure, and remarkable superaerophobic efficacy. As an unconventional processing method, the reconstructed morphology of substrate surface bears the responsibility of superaerophobicity, thus liberating the structural constraints on loaded materials. Since this key of coupling effect is transferred from the loaded materials to substrate, we provided a new general scheme for synthesizing superaerophobic electrodes. The successful introduction of femtosecond laser will open a new idea to synthesize self-supporting electrodes for gas-involving reactions.

The magnetization reduction of hematite using biomass waste can effectively utilize waste and reduce CO 2 emission to achieve the goals of carbon peaking and carbon neutrality. The effects of temperatures on suspension magnetization roasting of hematite using biomass waste for evolved gases have been investigated using TG-FTIR, Py-GC/MS and gas composition analyzer. The mixture reduction process is divided into four stages. In the temperature range of 200–450 °C for mixture, the release of CO 2 , acids, and ketones is dominated in gases products. The yield and concentration of small molecules reducing gases increase when the temperature increases from 450 to 900 °C. At 700 °C, the volume concentrations of CO, H 2 and CH 4 peak at 8.91%, 8.90% and 4.91%, respectively. During the suspension magnetization roasting process, an optimal iron concentrate with an iron grade of 70.86%, a recovery of 98.66% and a magnetic conversion of 45.70% is obtained at 700 °. Therefore, the magnetization reduction could react greatly in the temperature range of 600 to 700 °C owing to the suitable reducing gases. This study shows a detail gaseous evolution of roasting temperature and provides a new insight for studying the reduction process of hematite using biomass waste.

Much attention has been paid on research and development on solid electrolytes for all-solid-state Li batteries. Although halide solid electrolytes such as Li 3 YCl 6 and Li 3 InCl 6 are promising due to fast Li ion conductivity and oxidation-resistant against positive electrode, a better understanding of their reactivity with atmospheric H 2 O is required for commercialization. In this study, the gas evolution tolerances of Li 3 YCl 6 and Li 3 InCl 6 were investigated. Temperature-programmed desorption mass spectrometry (TPD-MS) experiments at dew points below − 60 °C and gas detector tube experiments at dew points of − 30 °C both revealed significant differences in the H 2 O and HCl evolution behavior of Li 3 YCl 6 and Li 3 InCl 6 . In TPD-MS, the onset temperature of HCl evolution for Li 3 YCl 6 (~ 100 °C) was significantly lower than that for Li 3 InCl 6 (~ 220 °C), indicating that Li 3 InCl 6 solid electrolytes have superior gas evolution tolerance. This difference may be attributable to differences in the retention of H 2 O derived from the material synthesis stage and from contact with the atmosphere during the measurements. In particular, based on first-principles calculations, the low-temperature HCl evolution observed in Li 3 YCl 6 was ascribed to the partial replacement of Cl − ions by OH − ions upon contamination with trace H 2 O. Because the heating and drying of solid electrolytes (including slurries) are inevitable processes during battery manufacturing, these findings can aid in the rational design of halide solid electrolytes for all-solid-state batteries.

The objective of this study was to investigate and visualize the initiation and propagation of crevice corrosion in grade 2205 duplex stainless steel by means of time-lapse imaging. Transparent Poly-Methyl-Meth-Acrylate washer and disk were coupled with duplex stainless steel to create an artificial crevice, with electrochemical monitoring applied to obtain information about the nucleation and propagation characteristics. All nucleation sites and corroding areas inside crevices were recorded in situ using a digital microscope set-up. Localized corrosion initiated close to the edge of the washer, where the crevice gap was very tight, with active corrosion sites then propagating underneath the disk into areas with wider gaps, towards the crevice mouth. The growth was associated with a rise in anodic current interlaced with sudden current drops, with parallel hydrogen gas evolution also observed within the crevice. The current drops were associated with a sudden change in growth direction, and once corrosion reached the crevice mouth, the propagation continued circumferentially and in depth. This allowed different corrosion regions to develop, showing selective dissolution of austenite, a region with dissolution of both phases, followed by a region where only ferrite dissolved. The effect of applied electrochemical potential, combined with time-lapse imaging, provides a powerful tool for in situ corrosion studies.

The paper describes the first comparative study of combustion of powder and granular mixtures [Ti + C and (Ti + C) + 20% Cu], in which the granule size is different and the titanium particle size varies from 31.5 to 142  m. It is revealed that the burning rate of (Ti + C) + 20% Cu powder mixture is higher than that of Ti + C, despite its lower combustion temperature. The use of the “gasless\" combustion theory for determining the kinetic parameters of the process using the burning rate of the powder mixture leads to a negative apparent activation energy, which indicates that the traditional approach is inapplicable. The results are explained within the framework of the convective-conductive combustion model by the decelerating effect of impurity gases released when the component particles are warmed up ahead of the combustion front. The burning rates of the granular mixtures with (0.6–1.7)-mm granules are used to calculate the burning rate of the granule substance, i.e., the burning rate of the powder mixture, in which the influence of impurity gases is leveled. The ratio of the burning rates of a substance inside granules and powder samples determines the measure of influence of impurity gas evolution on the burning rate of a powder mixture.

Specific rates of evolution of volatile compounds in vacuum from a range of different-type adhesive materials determined by means of kinetic thermodesorption mass spectrometry are presented. A method for calculating the initial concentration of volatile compounds, diffusion coefficients, and gas evolution from a cured adhesive material after thermal vacuum outgassing is proposed.

The thermal stability of polyether ketone, polyetheretherketone, polyarylene ketone at 400-500 °C was studied by gas chromatography. It was found out that the thermal destruction of polyetherketones and polyetheretherketones begins with the rupture of the ketone group, and polyarylene ketones with the detachment of the methyl group and the rupture of the ether linkage of the diane fragment.

In order to optimize and design new bubbly flow reactors, it is necessary to predict the bubble behavior and properties with respect to the time and location. In gas-liquid flows, it is easily observed that the bubble sizes may vary widely. The bubble size distribution is relatively sharply defined, and bubble rises are uniform in homogeneous flow; however bubbles aggregate, and large bubbles are formed rapidly in heterogeneous flow. To assist in the analysis of these systems, the volume, size and other properties of dispersed bubbles can be described mathematically by distribution functions. Therefore, a mathematical modeling tool called the Population Balance Model (PBM) is required to predict the distribution functions of the bubble motion and the variation of their properties. In the present paper, two rectangular bubble columns and a water electrolysis reactor are modeled using the open-source Computational Fluid Dynamic (CFD) package OpenFOAM. Furthermore, the Method of Classes (CM) and Quadrature-based Moments Method (QBMM) are described, implemented and compared using the developed CFD-PBM solver. These PBM tools are applied in two bubbly flow cases: bubble columns (using a Eulerian-Eulerian two-phase approach to predict the flow) and a water electrolysis reactor (using a single-phase approach to predict the flow). The numerical results are compared with measured data available in the scientific literature. It is observed that the Extended Quadrature Method of Moments (EQMOM) leads to a slight improvement in the prediction of experimental measurements and provides a continuous reconstruction of the Number Density Function (NDF), which is helpful in the modeling of gas evolution electrodes in the water electrolysis reactor.

Energy storage with high energy density and low cost has been the subject of a decades-long pursuit. Sodium-ion batteries are well expected because they utilize abundant resources. However, the lack of competent cathodes with both large capacities and long cycle lives prevents the commercialization of sodium-ion batteries. Conventional cathodes with hexagonal-P2-type structures suffer from structural degradations when the sodium content falls below 33%, or when the integral anions participate in gas evolution reactions. Here, we show a “pillar-beam” structure for sodium-ion battery cathodes where a few inert potassium ions uphold the layer-structured framework, while the working sodium ions could diffuse freely. The thus-created unorthodox orthogonal-P2 K 0.4 [Ni 0.2 Mn 0.8 ]O 2 cathode delivers a capacity of 194 mAh/g at 0.1 C, a rate capacity of 84% at 1 C, and an 86% capacity retention after 500 cycles at 1 C. The addition of the potassium ions boosts simultaneously the energy density and the cycle life. The specific capacity of P2-type sodium-ion battery cathode is limited because full extraction of Na ions leads to structural degradation. Here authors report pillar-beam structured material to overcome this issue by using K pillar ions to uphold the transition metal layers upon extraction of Na ions.

Lithium carbonate plays a critical role in both lithium-carbon dioxide and lithium-air batteries as the main discharge product and a product of side reactions, respectively. Understanding the decomposition of lithium carbonate during electrochemical oxidation (during battery charging) is key for improving both chemistries, but the decomposition mechanisms and the role of the carbon substrate remain under debate. Here, we use an in-situ differential electrochemical mass spectrometry-gas chromatography coupling system to quantify the gas evolution during the electrochemical oxidation of lithium carbonate on carbon substrates. Our results show that lithium carbonate decomposes to carbon dioxide and singlet oxygen mainly via an electrochemical process instead of via a chemical process in an electrolyte of lithium bis(trifluoromethanesulfonyl)imide in tetraglyme. Singlet oxygen attacks the carbon substrate and electrolyte to form both carbon dioxide and carbon monoxide—approximately 20% of the net gas evolved originates from these side reactions. Additionally, we show that cobalt(II,III) oxide, a typical oxygen evolution catalyst, stabilizes the precursor of singlet oxygen, thus inhibiting the formation of singlet oxygen and consequent side reactions. Lithium carbonate is ubiquitous in lithium battery chemistries and leads to overpotentials, however its oxidative decomposition is unclear. Here, the authors study its decomposition in ether electrolyte, clarify the role of the carbon substrate, and propose a route to limit released singlet oxygen.