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Co-doped magnetic Mn3O4 was synthesized by the solvothermal method and adopted as an effective catalyst for the degradation of oxytetracycline (OTC) in water. Synergistic interactions between Co-Mn3O4 and Fe3O4 not only resulted in the enhanced catalytic activity through the activation of peroxymonosulfate (PMS) to degrade OTC but also made Fe3O4/Co-Mn3O4 easy to be separated and recovered from aqueous solution. 94.2% of OTC could be degraded within 60 min at an initial OTC concentration of 10 mg L−1, catalyst dosage of 0.2 g L−1, and PMS concentration of 10 mM. The high efficiency of OTC removal was achieved in a wider pH range of 3.0–10.0. Co (II), Co (III), Fe (II), Fe (III), Mn (II), Mn (III), and Mn (IV) on Fe3O4/Co-Mn3O4 were identified as catalytic sites based on XPS analysis. The free radical quenching experiments showed that O2•− radicals and 1O2 played the main role in the degradation process and the catalytic degradation of OTC involved both free radical and non-free radical reactions. Eventually, the intermediates of OTC degradation were examined, and the possible decomposition pathways were proposed. The excellent catalytic performances of Fe3O4/Co-Mn3O4 came from the fact that the large specific surface area could provide abundant active sites for the activation of PMS and the redistribution of inter-atomic charges accelerated the redox reactions of metal ions. The high degradation efficiency and rate constant of OTC in actual water samples indicated that Fe3O4/Co-Mn3O4 had a good practical application potential. [ABSTRACT FROM AUTHOR]

The development of highly efficient, economical, and sustainable electrocatalysts based on non‐noble metals for hydrogen evolution reaction (HER) is of vital significance for large‐scale renewable energy storage. Herein, an effective synthetic strategy for the construction of MoO2 nanoflowers decorated with metallic Cu/Cu2O nanoparticles (NPs) on Ni foam (NF) (Cu2O/MoO2@Cu/NF) with a simple two‐step method is reported. The prepared Cu2O/MoO2@Cu/NF as an electrocatalyst exhibits outstanding reactivity and remarkable stability in alkaline solution. The onset overpotential of Cu2O/MoO2@Cu/NF approaches 0 V. An overpotential as low as 32 mV is obtained to afford a current density of 10 mA cm−2, comparable with Pt/C catalysts. The Tafel slope is low at 40 mV dec−1 as well. The involvement of zero‐valent Cu greatly reduces the resistance. The well‐dispersed Cu/Cu2O NPs on the sphere‐like MoO2 nanoflowers exaggerate the surface area. The ringent channels provide the fast release of evolved bubbles. Furthermore, the enhanced conductivity and large surface area lead to significant activity in HER. Herein, a novel design and facile synthesis of a highly efficient electrocatalyst with catalytic activity that is comparable to a Pt/C catalyst is provided. [ABSTRACT FROM AUTHOR]

The fabrication of cost‐effective and performance‐advanced electrocatalysts is in great requirements for water splitting to achieve sustainable oxygen production. A simple and effective precursor of ZIF‐67 particles mounted on Cu(OH)2 nanorods was induced by a template alignment method. After annealing, hierarchical CoO polyhedron‐decorated CuO/Cu2O (CuOx) nanorods on Cu foam (denoted as CuOx@CoO NRs/CF) were achieved, which displayed the heterojunction in CuOx components, hierarchical configuration and outward active sites. These features, verified by HRTEM, SEM, XPS and EDX, optimized the oxygen evolution reaction (OER) electrocatalyst. Benefiting from its large electrochemical surface area and the synergetic effect between CuOx and CoO, CuOx@CoO NRs/CF exhibited considerable catalytic activity with a low overpotential of 254 mV to obtain a current density of 10 mA cm−2 in alkaline electrolyte and a scarce loss of the initial catalyst activity over 24 h and over 5000 cycles. This work provides a channel to enhance the performance in OER. [ABSTRACT FROM AUTHOR]

In order to develop efficient and earth-abundant catalysts for large-scale hydrogen evolution via water splitting, a Ni/Ni(OH)2 dual composition electrocatalyst was manufactured via a two-step electrodeposition procedure. The stepwise fabricated 3D hierarchical nanoarrays as well as the concurrent dual composition electrodeposition yielded a papillae-like hybrid crystal structure. The high electrochemically active surface area, defect-rich hybrid crystal structure, and synergistic effects of the dual composition provided an elevated catalytic performance. Only 53 mV overpotential was needed to deliver a current density of 10 mA cm−2 with a small Tafel slope of 54.5 mV dec−1 to catalyze the HER in alkaline media. Approximately 81% catalytic activity could be maintained after 20 h of continuous testing, demonstrating long-term stability. Our findings offer an efficient approach to design and fabricate efficient noble-metal-free alkaline HER electrocatalysts. [ABSTRACT FROM AUTHOR]

Developing high-performance nonprecious-metal electrocatalysts for the oxygen evolution reaction (OER) is crucial for efficient water splitting. Therefore, the reasonable design principle of catalyst, leading to high activity catalytic center and improving the accessibility of active sites, is undoubtedly crucial. Here, we used a kind of Prussian blue analogue (CoFe-PBA) nanoparticles to anchor the nitrogen-carbon doped CoFe 2 O 4 (CoFe 2 O 4 @NC) species to reduced graphene oxide aerogels as OER catalysts. The strong interaction between nanosized CoFe 2 O 4 @NC and the graphitic carbon shell led to synergistic effects in the OER, and the protection of the carbon shell guaranteed stability of the catalyst. As a result, the aerogel electrocatalyst exhibits more excellent activity and stability than the most advanced RuO 2 catalyst in OER under the same mass load in alkaline medium. It shows smaller overpotential of 250 mV to afford a current density of 10 mA cm−2 in a continuous working time of more than 70 hours. [Display omitted] • The catalyst has highly exposed active surface, multi-dimensional mass transfer pathway and good charge transfer ability. • The in-situ formation of nitrogen-carbon doped structure can greatly improve the catalytic activity and stability. • The binary active sites on the conductive GA network reduce the interfacial resistance and enhance catalytic activity. • The "Plum Pudding Model" structure integrates multiple requirements for catalyst design strategies. [ABSTRACT FROM AUTHOR]

Low-cost and earth-rich electrocatalysts with excellent catalytic activity in the electrochemical hydrogen evolution reaction (HER) are essential for large-scale renewable energy storage. Herein, we report a new type of core-shell Ni 2 P@CoP nanoarrays supported on nickel foam (NF) (Ni 2 P@CoP/NF) with large specific surface area, serving as an efficient cathode for hydrogen evolution reaction (HER). Plenty of tiny Ni 2 P nanosheets were tightly wrapped on the CoP nanowires, forming a rich heterostructure interface, which can provide more active sites and improve conductivity, thereby increasing their catalytic performance. What's more, the synergistic effect between Ni 2 P and CoP can promote the rapid electron transfer and improve the catalytic efficiency. The obtained Ni 2 P@CoP/NF NAs exhibited excellent HER activity with a low overpotential of 61 mV at 10 mA cm−2 and good durability in the alkaline media. The core-shell nanoarray structure of Ni 2 P@CoP/NF provides a novel method for the preparation of other heterojunction metal phosphides, which can be used to develop high performance HER electrocatalysts. [Display omitted] • Designed a new type of core-shell Ni 2 P@CoP nanoarrays supported on nickel foam. • The catalyst has a large specific surface area and rich heterostructure interfaces, which can provide more active sites. • The synergistic effect between Ni 2 P and CoP can promote the rapid electron transfer. • The obtained catalyst exhibits remarkable enhanced HER activities compared to pure Ni 2 P and CoP nanostructures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu-MOFs derived CNF/Cu-C dual-functional membrane catalyst was synthesized. • Simultaneously efficient visual detection and SPEF degradation of PFOA are proposed. • PFOA inhibited peroxidase-like activity of CNF/Cu-C by hindering Cu active sites. • Enhanced degradation and mineralization efficiency of PFOA via SPEF are achieved. • States of active Cu species is regulated for enhanced photo-electric property. Developing bi-functional materials to simultaneously detect and degrade persistent pollutant perfluorooctanoic acid (PFOA) is of significant importance for environmental and human health. In this study, a copper-based mimic enzyme colorimetric detecting sensor coupling with solar photo-electro-Fenton degradation (SPEF) system was built based on Cu/carbon nanofiber (CNF-Cu/C) membrane. Self-supporting flexible CNF-Cu/C membrane was successfully prepared by solvothermal method with further secondary seed growth and in-situ thermal reduction. Based on calcination temperature regulation, the obtained CNF-Cu/C membrane derived from MOFs/polyacrylonitrile (HKUST/PAN) membrane was characterized by 3D carbon fiber network dispersed with porous carbon skeleton embedded copper species, which exhibited good dispersibility, cycling stability and excellent electrical conductivity. With excellent peroxidase-like activity, CNF-Cu/C can rapidly detect PFOA based on the inhibition of color reaction of tetramethylbenzidine (TMB) with detection limit of 0.133 μM. Furthermore, CNF-Cu/C also exhibited outstanding optical properties and oxygen redox reaction (ORR) activity, and the removal efficiency of PFOA in Cu-SPEF system reached 98.22 % within 180 min under optimal conditions. Based on the results of free radical quenching experiment, EPR experiment and HPLC-MS experiments, the degradation mechanism and degradation path of PFOA by SPEF system were further speculated. [ABSTRACT FROM AUTHOR]

Due to the advantages of large specific surface area, high mass transfer efficiency and easy access to active sites, two dimensional (2D) nanomaterials provide a great opportunity for the construction of new versatile electrocatalysts with superior properties. Herein, a graphene-templated growth of MoS 2 -Ni 3 S 2 heterostructure with porous structure is successfully prepared on the Ni foam (MoS 2 /Ni 3 S 2 @G/NF) by one pot hydrothermal method. The electronic structure and surface properties of 2D chalcogenides are modified by heterogeneous interface and component engineering, so as to prepare a high-performance transition metal composite catalytic electrode for electrochemical reaction. The optimized MoS 2 /Ni 3 S 2 @G/NF shows excellent bifunctional activity and durability in alkaline medium. It only needs 53 mV and 265 mV overpotential to reach 10 mA cm−2 current density of HER and 20 mA cm−2 current density for OER, respectively. When the composite is used as an advanced electrocatalyst for water splitting, the 1.47 V voltage required to achieve a current density of 10 mA cm−2, which is better than the most non-noble metal electrocatalysts. The heterostructures between MoS 2 , Ni 3 S 2 and graphene are conducive to the synchronous chemical adsorption of hydrogen and oxygen-containing intermediates, which can improve the catalytic activity of overall water splitting. [Display omitted] • The synergy between MoS 2 nanosheets and Ni 3 S 2 particles enhances the intrinsic electrochemical activity of the material. • Graphene increases the load of active substances and regulates the interaction between electrons with faster carrier. • 3D nickel foam provides a binder free framework for catalytic reaction, greatly reducing charge transfer resistance. [ABSTRACT FROM AUTHOR]

A novel composite catalyst (Al-MOF/Fe 3 O 4 /PDA@Ag) was successfully synthesized through the deposition of Ag nanoparticles onto the magnetic Al-MOF/Fe 3 O 4 /PDA and characterized by several techniques, such as SEM, TEM, EDS, FT-IR, XRD, elemental analysis, AAS, XPS, BET, PES and VSM. The resulting Al-MOF/Fe 3 O 4 /PDA@Ag had rough surface, mesoporous structure, large surface area and magnetic property. Al-MOF/Fe 3 O 4 /PDA@Ag exhibited excellent catalytic performances, which removed 81.7% of ciprofloxacin (CIP), 80.1% of norfloxacin (NOR) and 98.2% of methyl orange (MO) within 40 min in the presence of 10 mM of NaBH 4. The catalyst could be separated easily with a magnet and reused effectively after reaction. Furthermore, the intermediate products of CIP degradation by Al-MOF/Fe 3 O 4 /PDA@Ag were detected and the possible degradation pathways were proposed. Additionally, the catalytic ability of Al-MOF/Fe 3 O 4 /PDA@Ag was further explored in practical application. MO, as a typical pollutant in river water, was rapidly decolorized with decolorization efficiency higher than 97.1% even at high initial concentration of 150 mg/L. Therefore, Al-MOF/Fe 3 O 4 /PDA@Ag could be regarded as a promising catalyst for the removal of organic pollutants due to its high catalytic activity, good reusability, easy preparation, rapid separation and high stability. Image 1 • Al-MOF/Fe 3 O 4 /PDA as support and stabilizer to load Ag NPs was synthesized as a novel catalyst. • Higher removal efficiency and fast degradation speed for CIP, NOR and MO were obtained by Al-MOF/Fe 3 O 4 /PDA@Ag. • The catalyst could be easily separated and showed good stability and reusability. • Al-MOF/Fe 3 O 4 /PDA@Ag NPs could efficiently degrade MO in environmental water samples. [ABSTRACT FROM AUTHOR]