Boosting the electron transfer efficiency of Fe3+/Fe2+ cycle in electro-Fenton process using molybdenum: Performance and DFT study

作者：Yanyu Zhang, Enric Brillas, Aimin Wang, Ignasi Sirés · 发表于：Chemical Engineering Journal · 年份：2024 · DOI：10.1016/j.cej.2024.157087 · 被引用次数：7 · 研究领域：Advanced oxidation water treatment、Electrocatalysts for Energy Conversion、Advanced battery technologies research

• More efficient electro-Fenton process with GDE cathode: Mo cocatalyst to recycle Fe 2+ . • Best acebutolol removal at pH 3.0: 10 mg L −1 Mo powder, 0.5 mM Fe 3+ , j = 30 mA cm −2 . • Mixture of oxidants: OH as main ROS, along with O 2 − and 1 O 2 at the Mo surface. • Fe 3+ /Fe 2+ cycle self-sustained by different valence states on Mo surface (Mo 0 , Mo 4+ , Mo 5+ , Mo 6+ ). • DFT analysis of acebutolol sites prone to nucleophilic and electrophilic attacks. A novel coupling of a gas-diffusion electrode (GDE)-based electro-Fenton (EF) system, using Fe 3+ and Mo powder as cocatalysts, is investigated. The proposed EF-Fe 3+ /Mo process enhanced the Fe 3+ /Fe 2+ cycle, ensuring the rapid consumption of electrogenerated H 2 O 2 . This resulted in a greater OH production from Fenton’s reaction, yielding a quick degradation of the β-blocker acebutolol selected as model organic pollutant. DSA anode yielded complete but slightly slower drug removal as compared to BDD. The best operation conditions at pH 3.0 were: 0.5 mM Fe 3+ and 10 mg L −1 Mo powder, applying a current density of 30 mA cm −2 . Specific scavengers disclosed the formation of OH from Fenton’s reaction, along with O 2 − and 1 O 2 at the Mo surface. Surface analysis by SEM, XRD, and XPS showed that the cycled Mo powder retained the same compact, porous, and rock-like structure as the pristine one, revealing the presence of Mo 0 , Mo 4+ , Mo 5+ and Mo 6+ species, which included oxides like MoO 2 and MoO 3 . DFT calculatio...