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[Display omitted] • Fe, Cu co-doped promotes electron transfer of ORR. • Fe, Cu co-doped adjust d-band of elements. • Fe, Cu act synergistically through redox coupling. • FeCu@CN shows the remarkable stability in application of MFC. Air cathode microbial fuel cell (AC-MFC) cannot be used on a large scale because of its low oxygen reduction reaction (ORR) efficiency. Despite the fact that bimetallic catalysts can greatly enhance the oxygen reduction rate by regulating the electronic structure of the active site, the flaws of insufficient exposure of the active site and easy metal agglomeration limit its catalytic activity. Herein, we report on the preparation of a stable heteroatomic substrate using a copper material organic framework as a precursor, covered by Fe-based active sites. As a result of dipole-dipole interactions, the reduced product Fe2+ forms a weak Fe-O surface that is conducive to the adsorption of active substances. The presence of Fe0 enhances the electrical conductivity of the catalytic, thus promoting ORR efficiency. Through redox coupling, the D-band center of Fe at FeCu@CN is optimized and brought close to the Fermi level to facilitate electron transfer. Notably, FeCu@CN demonstrates a superior power density of 2796.23 ± 278.58 mW m−3, far exceeding that of Pt/C (1363.93 ± 102.56 mW m−3), in the application of microbial fuel cells (MFCs). Meanwhile, the MFC-loaded FeCu@CN maintains excellent stability and outstanding output voltage after 1000 h, which provides feasibility for large-scale application. [ABSTRACT FROM AUTHOR]

Using capacitive deionization to remove heavy metal ions from water has received much attention, but the inferior salt adsorption capacity (SAC) of electrode materials has always limited its practical application. Herein, N, S co-doped two-dimensional (2D) porous glucose derived carbon nanosheets (NSPGC) was successfully fabricated, utilizing the gas exfoliation by calcination of thiourea. The NSPGC demonstrates distinct 2D lamellas, high specific surface area (2529 m2 g−1), hierarchical pore structure and high wettability. In electrochemical tests, a high specific capacitance (127 F g−1) and electrons/ions transport performance can be achieved in the NSPGC, moreover it showed a prominent SAC of 206.57 mg g−1 and recoverability in 100 mg L−1 CuSO 4 solution. Moreover, the density functional theory (DFT) calculation manifested the intrinsic affinity of Cu2+ improved by N, S co-doping, which played an essential role in enhancing the Cu2+ removal performance of CDI. Our work provided a new insight into the preparation of high-performance CDI electrode materials for Cu2+ removal and promoted the application of CDI in heavy metal wastewater. [Display omitted] • N, S co-doped two-dimensional (2D) porous glucose derived carbon nanosheets (NSPGC) were synthesized by one-step pyrolysis. • NSPGC have distinct 2D lamellas, high specific surface area (2529 m2 g-1), hierarchical pore structure and high wettability. • NSPGC exhibits excellent Cu2+ adsorption capacity (206.57 mg g-1). • N, S co-doping enhances the affinity of carbon layer for Cu2+ and improve its adsorption capacity. [ABSTRACT FROM AUTHOR]

The metal-free carbon-based catalyst with low cost and high oxygen reduction reaction (ORR) activity is urgently desired to satisfy the demands of microbial fuel cells (MFCs). However, it is still a great challenge to develop a facile and feasible strategy to construct efficient active sites of heteroatom doping for carbon-based electrocatalyst. Herein, we report a strategy based on an ammonium fluoride (NH 4 F) gas-steamed metal-organic frameworks (MOFs) to heighten structural defects and density of N, F active sites of metal-free catalyst. Oxygen temperature-programmed deposition and density functional theory results confirm that the NH 4 F gas-steamed process greatly enhances the adsorption affinity of O 2 and oxygen intermediates on the catalysts. The resulted N and F co-doped porous carbon cage (FNC-15) demonstrates outstanding ORR catalytic activity and long-term stability in alkaline and neutral electrolytes. This work proposes a facile and efficient in situ gas-steamed strategy to develop metal-free cathode catalysts with superior performance. [Display omitted] • NH 4 F gas-steamed strategy introduce defects and N, F active sites within catalysts. • Defect sites enhance the oxygen molecules adsorption affinity of catalysts. • Remarkably enhanced ORR catalytic activity and stability. • The metal-free FNC-15 exhibits superior performance in microbial fuel cell. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co/Fe co-doped ZIF-8 derived porous carbon for CDI removal of Cu2+ ions. • A stable carbon cage encapsulated a porous carbon structure. • CoFe-NC has better selectivity for Cu2+ ions. • CoFe-NC shows higher electrosorption capacity in application of CDI. Due to a threat to human life from heavy metal ions pollution, unprecedented interest has been gained in the development of water purification technologies. Here, we explore another new approach to exploit a prospective carbon material for removing copper ions from aqueous solution based on rapid and easy capacitive deionization (CDI). Reasonable carbon materials modification with ideal composition and improved morphological structure is essential to additionally optimize the capabilities of CDI. We prepared a nitrogen-rich hierarchically porous carbon composites (CoFe-NC) with uniform cobalt (Co) and iron (Fe) doped metal in carbon skeleton by a simple impregnation and pyrolysis method, derived from zeolitic imidazolate framework-8, to use as highly effective CDI electrode for copper ions removal. The addition of Fe can facilitate the uniform dispersion of metals, and enable the formation of a stable carbon cage after pyrolysis. It can sufficiently expose active sites of the electrode materials and promote interfacial charge transfer, thus improving CDI electrosorption efficiency. CoFe-NC composites electrode can achieve outstanding deionization capacity (91.31 mg g−1) in 25 mg L−1 CuSO 4 solution. The carbon cage structure of CoFe-NC not only prevents aggregation of metals and avoids destruction of rich multistage pore system by pyrolysis, but also induces a faster ions transport rate. In addition, density functional theory calculations demonstrated that the co-doping of Co and Fe can remarkably increase the adsorption energies of Cu2+ ions, leading to excellent selectivity, which indicates that CoFe-NC composites can be a desired CDI electrode material. [ABSTRACT FROM AUTHOR]

In this work, CeMn 1-x M x O 3 (M = Cu, Fe and Co) perovskites were synthesized and used as efficient heterogeneous catalyst for degrade of tetracycline chloride (TC-HCl) via photocatalysis coupled peroxymonosulfate (PMS) oxidation under visible-light illumination. Metal doping significantly improved the catalytic activity of perovskites. The CeMn 0.6 Co 0.4 O 3 /PMS/Vis system demonstrated excellent performance that 96.4% of 60 mg/L of TC-HCl was degraded within 30 min with a high reaction rate constant of 0.136 min−1, which is about 4.3 times higher than that of CeMnO 3 , and almost 4.4 times higher than that of pure PMS. Results confirmed the addition of Co led to mixed valence states of Mn (III)/Mn (Ⅳ) and Co (II)/Co (III) in the perovskite structure, promoting the electron transfer from the CeMn 0.6 Co 0.4 O 3 to PMS. Moreover, CeMn 0.6 Co 0.4 O 3 exhibited good stability over a wide pH range (3.0–11.0). The rapid transformation of Co (II)/Co (III) redox pairs is critical for PMS activation as the limiting step. Superoxide radicals (•O 2 −), electron (e−) and sulfate radical (SO 4 −•) were the dominant oxidative species responsible for removing TC-HCl. This work proposed some new insights to understand the heterogeneous reaction mechanism during PMS oxidation and photocatalytic process and promote the development of perovskites catalyst for removal of organic pollutants. [Display omitted] • Co doping promote cycles of Co2+/Co3+, Mn3+/Mn4+ and formation of oxygen vacancies. • •O 2 −, e− and SO 4 −• are primary radicals for catalytic degradation of TC-HCl. • Coupling of photocatalysis and PMS oxidation improved catalytic activity. • Vis/CeMn 0.6 Co 0.4 O 3 /PMS system degraded 96.4% TC-HCl within 30 min. [ABSTRACT FROM AUTHOR]

• Synergistic electrosorption of HBC bilayers and MoS 2 for Cu2+ complexation. • HBC shows excellent structural stability before and after MoS 2 loading. • High selective ion removal effect is still achieved in the presence of complex ions. • Used as an electrode in capacitive deionization technology. Capacitive deionization has been considered as a promising wastewater treatment technology because of its low-cost and highly efficient. Herein, we prepared hollow bowl-type carbon materials loaded with molybdenum sulfide (HBC-MoS 2) composites and fabricated it as an innovative electrode material to remove Cu2+ in a multi-ion coexistence system. With the synergistic effect of electric double layer (EDL) and complexation between MoS 2 and Cu2+, the HBC-MoS 2 -0.02 electrode achieved effective removal of copper ions from low concentration wastewater (25 mg/L) and high electrosorption capacity of 28.97 mg g−1 at 1.0 V. Even in the presence of competing ions (Na+/Zn2+/Cu2+), the HBC-MoS 2 -0.02 electrode still can effectively remove Cu2+ with a final adsorption capacity of 28 mg g−1, showing its superiority. The mechanism of Cu2+ removal by HBC-MoS 2 is mainly due to the synergistic effect of EDL and complexation. [ABSTRACT FROM AUTHOR]

Exploiting a facile way to synthesize low-cost and high-performance oxygen reduction reaction (ORR) catalysts is a core issue in microbial fuel cells (MFCs). Hence, a facile and extensible method has been developed to prepare efficient ORR catalysts by using robust UiO-66 as a precursor, modified with melamine and trithiocyanuric via the impregnation method. Benefiting from the hierarchical structure of UiO-66, the NS@UiO-66 has excellent stability, more active sites and improved mass transfer. Significantly, the half-wave potential and the current density of the NS@UiO-66 are 0.546 V vs. RHE and 6.19 mA cm−2 respectively, which is better than that of benchmark Pt/C in neutral conditions. Furthermore, the power density of MFCs assembled with the NS@UiO-66 catalyst is 318.6 ± 2.15 mW m−2. The density functional theory calculation demonstrates that the reaction barrier can be reduced effectively for accelerating the ORR process through the synergistic effect of N and S. The NS@UiO-66, as an ideal candidate to substitute for the commercial Pt/C counterpart, is expected to promote the scaling-up production and application of MFCs due to low-cost elements doping and facilely synthetic method. [Display omitted] • A facile synthesis way for preparing NS@UiO-66 porous carbon is proposed. • UiO-66 is a stable platform exposing more active sites and boosting mass transfer. • N, S co-doping induces charge redistribution and reduces the activation barrier. • The stable NS@UiO-66 shows great ORR property and application prospects in MFCs. [ABSTRACT FROM AUTHOR]