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Electrofluorochromic (EFC) materials and devices with controllable fluorescence properties show great application potential in advanced anticounterfeiting, information storage and display. However, the low color purity caused by the broad emission spectra and underperforming switching time of the existing EFC materials limit their application. Through biomimetic exploration and the study of reversible electrochemical responsive coordination reactions, boron–nitrogen embedded polyaromatics (B,N‐PAHs) with narrow‐band emission and high color purity have been successfully integrated into EFC systems, which also help to better understand the role of boron in biological activity. The EFC device achieve good performance containing quenching efficiency greater than 90% within short switching time (ton: 0.6 s, toff: 2.4 s), and nearly no performance change after 200 cycles test. Three primary color (red, green, and blue) EFC devices are successfully prepared. In addition, new phenomena are obtained and discussed in this biomimetic exploration of related boron reactions. The success and harvest of this exploration are expected to provide new ideas for optimizing properties and broadening applications of EFC materials. Moreover, it may provide ideas and reference significance for further exploring and understanding the function of boron compounds in biological systems. [ABSTRACT FROM AUTHOR]

Boron-doped polycyclic aromatic hydrocarbons exhibit excellent optical properties, and regulating their photophysical processes is a powerful strategy to understand the luminescence mechanism and develop new materials and applications. Herein, an electrochemically responsive B–O dynamic coordination bond is proposed, and used to regulate the photophysical processes of boron-nitrogen-doped polyaromatic hydrocarbons. The formation of the B–O coordination bond under a suitable voltage is confirmed by experiments and theoretical calculations, and B–O coordination bond can be broken back to the initial state under opposite voltage. The whole process is accompanied by reversible changes in photophysical properties. Further, electrofluorochromic devices are successfully prepared based on the above electrochemically responsive coordination bond. The success and harvest of this exploration are beneficial to understand the luminescence mechanism of boron-nitrogen-doped polyaromatic hydrocarbons, and provide ideas for design of dynamic covalent bonds and broaden material types and applications. Boron-doped polycyclic aromatic hydrocarbons with dynamic covalent bonds have interesting optical properties, but electricity-responsive bonds are less studied. Here, the authors report an electrochemically responsive B-O coordination bond with short switching time. [ABSTRACT FROM AUTHOR]

Given the background of significant Coal Mine gas disasters worldwide, the research and development of efficient gas control technologies have become critical to ensuring mining safety. CO 2 gas fracturing (CO 2 -Frac), an innovative technology for Coal Mine gas control, has demonstrated efficiency in various mining areas across China. However, its application in outburst-prone coal seams is not yet fully understood. This study presents a field-scale CO 2 -Frac project conducted in an outburst Coal Mine in China, specifically the Pingshu Coal Mine, where the previously employed dense-borehole gas extraction technology failed to efficiently achieve gas extraction and outburst prevention. The CO 2 -Frac plan was evaluated through fracture propagation experiments utilizing both single-hole and dual-hole configurations, highlighting the advantages of the dual-hole CO 2 -Frac method. Subsequently, on-site gas extraction tests were conducted to further assess the efficacy of the CO 2 -Frac plan. The results indicate that (1) In the dual-hole CO 2 -Frac scheme, the fractured and pressure relief area expanded to approximately 26.82 m 2 , which is 220% larger than that of the single-hole scheme. (2) The dual-hole CO 2 -Frac significantly enhanced gas extraction effectiveness, increasing the flow rate from 0.026 to 0.216 m 3 /min in a 100m borehole, a 7.3-fold improvement. Additionally, the gas extraction period to reach the standard was reduced from 20 to 6 days. These findings conclusively demonstrate that the dual-hole CO 2 -Frac technique is an effective method for safe excavation in outburst-prone coal seams, providing both theoretical and practical validation for its application in similar geological settings., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Considering the alarming frequency of coal mine gas disasters globally, there is an urgent need to develop efficient gas control technologies to ensure mining safety. This study focuses on the problem of high peak gas emission restriction in the process of coal roadway tunneling in outburst coal seams, taking the No. 15 outburst coal seam of the Pingshu Coal Mine as the research object. Based on coal sample testing analysis and the application of CO 2 gas fracturing (CO 2 -Frac) in coal mines, a comprehensive evaluation was conducted on pore-fracture structure alteration and homogenization gas emission effect induced by CO 2 -Frac, providing technical solutions for coal mine safety production. The results are as follows: (1) CO 2 -Frac induces fracture propagation and the development of three types of fracture structures: Tri-Wing Fracture, Damage Markers, and Coal Matrix Fragmentation. (2) Following CO 2 -Frac at 150 MPa, the pore volume and average diameter of pores in the 100-10,000 nm range increased by 128% and 61%, respectively, compared to the pre-CO 2 -Frac state. (3) During the excavation period, continuous monitoring of the airflow for 3 days showed a significant homogenization of gas emission, with a maximum value of 0.450% and a variance value of 0.0031, indicating a reduction of 31% and 68%, respectively. These results reveal several key findings: The pore-fracture structure alteration enhances gas diffusion and permeation, providing high-speed pathways for gas migration, resulting in a substantial increase in gas extraction efficiency. During coal cutting, the modified coal exhibits homogenized gas emission, eliminating the high peak phenomenon and achieving safe and efficient mining. These findings demonstrate that CO 2 -Frac has broad potential in gas emission homogenization for widespread application in coal mines with similar gas geological conditions., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)