Jiang-Yan Xue,Fei-Long Li,Zhong-Yin Zhao,Cong Li,Chun-Yan Ni,Hong-Wei Gu,David James Young,Jian-Ping Lang
Design and synthesis of non-noble metal electrocatalysts with high activity and durability for the electrolysis of water is of great significance for energy conversion and storage. In this work, we prepared a series of Fe-doped MoS2 nanomaterials by simple one-pot solvothermal reactions of (NH4)2MoS4 with FeCl3·6H2O. An optimized working electrode of Fe-MoS2-5 displayed high hydrogen evolution reaction (HER) activity with a relatively small overpotential of 173 mV to achieve a current density of 10 mA cm–2 in 0.5 M H2SO4, along with no significant change in catalytic performance even after 1000 cyclic voltammetry (CV) cycles. Fe-MoS2 nanoparticles on nickel foam (NF; denoted as Fe-MoS2/NF) exhibited an overpotential of 230 mV at 20 mA cm–2 for the oxygen evolution reaction (OER) and 153 mV at 10 mA cm–2 for the HER in 1.0 M KOH electrolyte. Fe-MoS2/NF was stable for more than 140 h under these conditions. Furthermore, the two electrode system of Fe-MoS2/NF (anode)//Fe-MoS2/NF (cathode) electrodes demonstrated excellent electrocatalytic activity toward overall water splitting with a low potential of 1.52 V at 10 mA cm–2 in 1.0 M KOH electrolyte.
Xi Chen,Songrong Li,Peizhen Yang,Yunfeng Chen,Cheng Xue,Yuhan Long,Jiayan Han,Jianming Su,Wenli Huang,Dongfang Liu
Peroxymonosulfate (PMS) heterogeneous catalysis dominated by nonradical pathway showed excellent adaptability for pollutant removal in complex water matrixes. Herein, ultra-small Fe-doped MoS 2 nanosheets with N-doped carbon intercalation (CF-MoS 2 ) were synthesized via a one-step hydrothermal method to treat high salinity organic wastewater. CF-MoS 2 exhibited an expanded interlayer spacing by 1.63 times and the specific surface area by 9 times compared with Fe-doped MoS 2 (F-MoS 2 ), substantially increasing the active sites. Homogeneous Fe 2+ catalytic experiments confirmed that the promotion of carbon intercalated MoS 2 (C-MoS 2 ) on Fe 3+ /Fe 2+ redox cycle was much higher than pure MoS 2 . Besides, the considerable removal of tetracycline (TC) under high salinity conditions (0–7.1%) was attributed to the dominant role of PMS nonradical oxidation pathways, including 1 O 2 and surface-bound radicals. The catalytic sites included Fe 3+ /Fe 2+ , Mo 4+ /Mo 5+ /Mo 6+ , C=O, pyridine N, pyrrolic N and hydroxyl groups . Finally, density functional theory (DFT) was employed to get the radical electrophilic attack sites and nucleophile attack sites of TC, and the results were consistent with the TC degradation products determined by HPLC-MS. This work would broaden the application of MoS 2 -based catalysts, especially for PMS catalytic removal of organic pollutants from high salinity wastewater.
The novel Fe-doped MoS2/granulated activated carbon (GAC) particle electrodes (FMG PEs) were controllably synthesized by a hydrothermal method and used in the three-dimensional (3D) electroactivation of peroxydisulfate (E-PDS-FMG) for carbamazepine (CBZ) degradation. The performance, mechanism, and influencing factors of CBZ degradation by the E-PDS-FMG system were systematically discussed. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) analyses showed that the E-PDS-FMG system has an excellent conductivity and a high electron transfer rate and exhibited a superior electrocatalytic performance for CBZ degradation. A CBZ removal rate greater than 99% can be achieved within 25 min under the conditions of FMG dosage of 0.4 g L−1, PDS concentration of 2.0 mM, current density of 1.0 mA cm−2, and initial pH value of 5. Sulfate radicals (SO4·−) and hydroxyl radicals (OH) were recognized as the major active species through quenching experiments and electron paramagnetic resonance (EPR) measurement. In addition, Fe (IV) was also involved in the E-PDS-FMG system according to the transformation of methyl phenyl sulfoxide (PMSO) to methyl phenyl sulfone (PMSO2). Furthermore, the possible mechanism of the E-PDS-FMG system was proposed. FMG PEs were applied as the catalyst and particle electrodes for PDS activation, improving the yield of OH, SO4·−, and Fe (IV). The increase of FMG dosage and PDS concentration accelerated the degradation of CBZ, and the E-PDS-FMG system exhibited a high degradation ability on CBZ removal in a wide pH range. The results all indicate that the E-PDS-FMG system is a promising technology for organic pollutant removal from water due to its excellent electrocatalytic performance and remarkable stability.
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