Zilong Zhang,Xia Qin,Cuicui Xu,Fanbin Zhang,Xinrui Liu,Yumei Yang
In this study, an electro-Fenton gas diffusion electrode featuring air self-respiration was fabricated by incorporating carbon nanotubes, carbon nitride, and polytetrafluoroethylene onto graphite felt. The fabrication process involved a synergistic approach of ultrasonic impregnation and vacuum filtration, establishing a gas–liquid-solid tri-phase interface both on the surface and within the electrode. This preparation method facilitates autonomous air intake, diffusing it to the tri-phase reaction interface, thereby eliminating the necessity for aeration and reducing operational costs. The optimal electrode preparation conditions were determined through Box-Behnken Design response surface experiments, leading to the enhancement of H 2 O 2 production conditions. Under the optimized conditions, H 2 O 2 accumulation reached 45.83 mg L −1 cm −2 h −1 , surpassing the performance achieved with conventional ultrasonic impregnation and vacuum filtration methods. Furthermore, the performance of self-breathing and the impact factors are explored. Finally, the electrode’s efficacy was demonstrated through the degradation of phenol and bisphenol A with concentrations of 100 mg L −1 exhibiting degradation rates of 92 % and 95 %, respectively, within 60 min.
Fanbin Zhang,Xia Qin,Cuicui Xu,Xiyang Li,Hongyun Ren,Xingwei Tao,Xujie Lan
A novel self-breathing gas diffusion electrode was developed by loading carbon nanotubes (CNTs) and carbon black (CB) onto the surface of graphite felt through vacuum filtration. This electrode features a well-structured mesoporous network and a stable three-phase interface, which enable efficient oxygen mass transfer and enhance the self-breathing capability. The incorporation of carbon nanotubes and carbon black significantly boosts the electrode's catalytic performance. In a dual-chamber reactor operating at a current density of 12 mA/cm 2 and an initial pH of 3, the system achieved an H 2 O 2 concentration of 4,691 mg/L within 1 hour, with an energy consumption of 6.58 kWh/kg H 2 O 2 substantially outperforming conventional gas diffusion electrodes. The dynamic pH regulation in the dual-chamber system optimizes the 2e - ORR pathway, leading to corresponding changes in proton transfer pathways and adsorbed species within the Helmholtz plane. Additionally, the presence of reactive hydrogen (H*) enhances the chemisorption of O 2 and facilitates its hydrogenation to form the *OOH intermediate. The electrode exhibited excellent stability, maintaining H 2 O 2 yields above 4000 mg/L over 5 cycles and nearly complete degradation of the simulated contaminants within 30 min in an electro-Fenton system application. These results highlight the electrode's potential for efficient H 2 O 2 synthesis and environmental remediation.
Yanwen Zhu,Zhaoliang Hu,Yunen Liu,Tingcai Yan,Ling Liu,Yanqun Wang,Bing Bai
Hydrogen sulfide (H 2 S), or dihydrogen sulfane (H 2 S n ), acts as a signal molecule through the beneficial mechanism of persulfidation, known as the post-translational transformation of cysteine residues to persulfides. We previously reported that Glutathione (GSH) could regulate enzyme activity through S-desulfurization or glutathionylation of residues to generate protein-SG or protein-SSG, releasing H 2 S. However, little is known about the mechanisms by which H 2 S n and GSH affect the disulfide bonds . In this study, we provide direct evidences that H 2 S n and GSH modify the sulfhydryl group on Cys272, which forms disulfide bonds in acetylcholinesterase (AChE), to generate Cys-SSH and Cys-SSG, respectively. Glutathionylation of disulfide is a two-step reaction based on nucleophilic substitution, in which the first C S bond is broken, then the S S bond is broken to release H 2 S. H 2 S n and GSH controlled self-breathing motion in enzyme catalysis by disconnecting specific disulfide bonds and modifying cysteine residues, thereby regulating AChE activity. Here, we elucidated H 2 S n and GSH mechanisms on disulfide in the AChE system and proposed a self-breathing control theory induced by H 2 S n and GSH. These theoretical findings shed light on the biological functions of H 2 S n and GSH on sulfhydryl and disulfide bonds and enrich the theory of enzyme activity regulation.
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