Potential of palm kernel shell as activated carbon precursors through single stage activation technique for carbon dioxide adsorption.

The critical bottleneck of electrocatalytic CO2 reduction reaction (CO2RR) lies in its low efficiency at high overpotential caused by competitive hydrogen evolution. It is challenging to develop an efficient catalyst achieving both high current density and high Faradaic efficiency (FE) for CO2RR. Herein, we synthesized fluorine-doped cagelike porous carbon (F-CPC) by purposely tailoring its structural properties. The optimized F-CPC possesses large surface area with moderate mesopore and abundant micropores as well as high electrical conductivity. When used as catalyst for CO2RR, F-CPC exhibits FE of 88.3% for CO at -1.0 V vs RHE with a current density of 37.5 mA·cm -2. Experimental results and finite element simulations demonstrate that the excellent CO2RR performance of F-CPC at high overpotential should be attributed to its structure-enhanced electrocatalytic process stemming from its cagelike morphology.

Fluorine Doped Cagelike Carbon Electrocatalyst: An Insight into the Structure-Enhanced CO Selectivity for CO2 Reduction at High Overpotential.

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2019 The Authors. Energy Science & Engineering published by the Society of Chemical Industry and John Wiley & Sons Ltd. 1College of Mining, Liaoning Technical University, Fuxin, Liaoning Province, China 2State Key Laboratory for GeoMechanics and Deep Underground Engineering, China University of Mining & Technology, Xuzhou, Jiangsu Province, China 3Energy and Mineral Engineering, Pennsylvania State University, University Park, Pennsylvania, USA

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

Sustainable mesoporous carbon nanostructures derived from lignin for early detection of glucose

Experimental analysis of the intensity and evolution of coal and gas outbursts

To characterize the pore features of outburst coal samples and investigate whether outburst coal has some unique features or not, one of the authors, working as the member of the State Coal Mine Safety Committee of China, sampled nine outburst coal samples (coal powder and block) from outburst disaster sites in underground coal mines in China, and then analyzed the pore and surface features of these samples using low temperature nitrogen adsorption tests. Test data show that outburst powder and block coal samples have similar properties in both pore size distribution and surface area. With increasing coal rank, the proportion of micropores increases, which results in a higher surface area. The Jiulishan samples are rich in micropores, and other tested samples contain mainly mesopores, macropores and fewer micropores. Both the unclosed hysteresis loop and force closed desorption phenomena are observed in all tested samples. The former can be attributed to the instability of the meniscus condensation in pores, interconnected pore features of coal and the potential existence of ink-bottle pores, and the latter can be attributed to the non-rigid structure of coal and the gas affinity of coal.

Pore characterization of different types of coal from coal and gas outburst disaster sites using low temperature nitrogen adsorption approach

Study on the difference of pore structure of anthracite under different particle sizes using low-temperature nitrogen adsorption method

The occurrence of a steeply inclined coal seam is extraordinary, and the coal body is seriously damaged by extrusion. The most steeply inclined coal seam is a high-gas or -outburst coal seam, and protective layer mining is the safest and most effective measure for regional prevention of coal and gas outburst. Based on considering the coefficient of lateral pressure and vertical height of the section, the deflection of the basic roof of the steeply inclined protective layer in a mine in western Henan, China, was calculated using the deflection calculation method of the thin-plate theory of elasticity. Using MATLAB to understand the deflection, the deflection curve was obtained. The law of rock movement and deformation in the mining process of the protective layer was studied by a similarity simulation experiment. The results show that, after mining, the roof mainly sinks slowly without large-scale collapse, and the largest rock strata movement is located in the upper part of the slope. Rock strata movement and fracture development can relieve the pressure of the protected layer and provide a channel for gas migration and drainage. The mining conditions of the protected layer will not be destroyed, and mining this type of protected layer in this mine has better safety and feasibility. The conclusions of this study have a guiding and scientific significance for the control of surrounding rock and the layout of gas drainage boreholes of under-protective steeply inclined coal seam mining.

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Study on Overburden Movement Deformation and Roof Breakage Law of Under-Protective Steeply Inclined Coal Seam Mining

The accuracy of the drainage radius plays a vital role in the gas drainage effect, and the establishment of the drainage model and numerical calculation of the model has an essential value for the accurate determination of the drainage radius. Based on the elastoplastic constitutive model of mining coal and rock mass, effective stress equation, gas content equation, gas flow continuity, and control equation established by predecessors, the gas-solid coupling model of coal-rock deformation and pressure-relief gas flow in protective layer mining was established in this paper. The numerical simulation prototype was based on the mining engineering practice of a short-distance and underprotective steep seam mining in a mine in western Henan of China. COMSOL Multiphysics coupling software was used to numerically calculate the coupling model, and the influence radius of different mining pressure-relief area and different drainage time was obtained. The results show that under the same geological conditions and mining conditions, the impact range of drilling in the pressure-relief area of the protected layer is larger than that of the nonrelief area. As the working face of the protection layer advances, the pressure-relief area of the protected layer gradually increases, the influence range of the drainage borehole increases, the drainage borehole has undergone a process of initial stress-stress concentration-stress reduction-stress recovery successively, and the strike drainage radius is larger than the inclined.

Numerical Simulation of Gas-Solid Coupling in Pressure-Relief Gas Drainage of Short-Distance and Underprotective Steeply Inclined Coal Seam Mining

In order to study the effects of different compression loads on the pore characteristics of coal, taking remolded coal as the research object, the mercury intrusion method was used to determine the pore structures of the briquettes under the compression loads of 50, 70, 90 and 110 MPa, and the Menger sponge model was used to conduct fractal research on the measured parameters. The results show that the compression load has a significant effect on the pore structure parameters of the briquettes. The hysteresis loop generated by the mercury-intrusion and mercury-extrusion curves of raw coal is small, and the pore connectivity is better. After different loads are applied for briquettes, the hysteresis loop becomes larger, and the pore connectivity becomes worse. From the process of the raw coal to the briquettes loaded at 50 and 70 MPa, the pore-specific surface area reduced from 5.069 m2/g to 1.259 m2/g, the total pore volume increased from 0.0553 cm3/g to 0.1877 cm3/g, and the average pore size increased from 43.6 nm to 596.3 nm. When the compression load reached 70 MPa, the specific surface area, total pore volume, and average pore diameter of briquettes remained basically stable with the change in the compression load. The minipores and visible pores and fissures of raw coal contribute 78% of the pore volume, and the micropores and minipores contribute 99% of the specific surface area. After being pressed into briquettes, the volume of mesopores and macropores increases, the volume of visible pores and fractures decreases and the volume of minipores changes little; additionally, the pore surface area contributed by mesopores and macropores increases, and the pore surface area contributed by micropores decreases, indicating that the effect of compression load on pores of 10–100 nm is not obvious, mainly concentrated in the 100–10,000 nm region. The fractal curve of briquettes is fitted into three sections, which are defined as low-pressure sections 1 and 2 and high-pressure section 3, and the fractal dimensions are D1, D2 and D3 respectively. The fractal dimension D1 of briquettes with different compression loads is close to 2, D2 is close to 3 and D3 is greater than 3. The pore structures of briquettes have obvious fractal characteristics in the low-pressure sections 1 and 2 but do not conform to the fractal law in the high-pressure section. Furthermore, in the micropore stage of briquettes, the measured surface area and volume are both negative, indicating that the mercury intrusion method used to test the pore structure of the loaded briquette is more likely to cause the collapse of and damage to the pores in the micropore (<10 nm) stage.

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Lingling Qi

Papers

Pore characterization of different types of coal from coal and gas outburst disaster sites using low temperature nitrogen adsorption approach

Study on the difference of pore structure of anthracite under different particle sizes using low-temperature nitrogen adsorption method

Study on Overburden Movement Deformation and Roof Breakage Law of Under-Protective Steeply Inclined Coal Seam Mining

Numerical Simulation of Gas-Solid Coupling in Pressure-Relief Gas Drainage of Short-Distance and Underprotective Steeply Inclined Coal Seam Mining

A Study on the Pore Structure and Fractal Characteristics of Briquettes with Different Compression Loads