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A carbon superstructure material (PTA-700) was synthesized by a simple self-assembly method and one-step carbonization, and showed remarkable high energy and long cycle life stability in lithium/sodium ion half battery. [Display omitted] Due to abundant resources and low prices, biomass-derived carbons as anodes for lithium ion batteries (LIBs) and sodium ion batteries (SIBs) have been widely reported. However, it is still a challenge to design a biomass-derived carbon material that has immunity to environmental influences, stable chemical composition and controllable morphology. In this paper, tannic acid (TA) as a precursor is first reported to synthesize rod structures with abundant mesopores and defects (PTA-700). These features can provide more active sites and space for lithium and sodium ions storage, which is conducive to lithium and sodium ions transfer. Excellent electrochemical performance is observed in LIBs (535 mAh/g after 100 cycles at 0.1 A/g) and SIBs (114.0 mAh/g after 3000 cycles at 1 A/g). Kinetics analysis and density functional theory (DFT) calculations were carried out to further analyze the superior lithium and sodium ions storage performance of PTA-700. More importantly, PTA-700 solves many problems faced by traditional biomass-derived carbons in commercialization. Our work suggests an effective way to develop high-performance biomass-derived carbon anode materials for LIBs and SIBs. [ABSTRACT FROM AUTHOR]

Electrocatalytic reduction of nitrite (NO2−) to ammonia (NH3) can simultaneously achieve wastewater treatment and ammonia production, but it needs efficient catalysts. Herein, Cu2O particles self-supported on Cu foam with enriched oxygen vacancies are developed to enable selective NO2− reduction to NH3, exhibiting a maximum NH3 yield rate of 7510.73 μg h−1 cm−2 and high faradaic efficiency of 94.21% at − 0.6 V in 0.1 M PBS containing 0.1 M NaNO2. Density functional theory calculations reveal the vital role of oxygen vacancies during the nitrite reduction process, as well as the reaction mechanisms and the potential limiting step involved. This work provides a new avenue to the rational design of Cu-based catalysts for NH3 electrosynthesis. [ABSTRACT FROM AUTHOR]

In this study, N/O co-doped cage-type biomass carbon (NOBC) was prepared through a simple and facile hydrothermal reaction and two-step carbonization method. As the anode of a potassium ion battery, NOBC displays a superhigh long-cycling performance and a super high rate performance. NOBC-2 provides an excellent reversible capacity of 251.2 mAh g−1 after 1500 cycles at 0.5 A g−1, and an excellent performance of 334.6 mAh g−1 at a high current density of 5 A g−1 (after 2000 cycles). The reversible capacity of 124.19 mAh g−1 can be maintained even after 5000 cycles at 10 A g−1. The excellent performance of NOBC is attributed to the unique hollow cage structure, internal 3D carbon network structure and N/O co-doping. Based on the results of detailed fundamental analysis, the pseudo-capacitance mechanism contributes to the higher K ion storage process in NOBC-2. Density functional theory (DFT) calculations further show that N/O double doping can promote the adsorption of K ions in biomass carbon materials and improve the conductivity of the materials. The simple synthesis route and excellent electrochemical performance provide new insights for the search for novel carbon-based K storage anode materials with high energy and long cycle life. The N/O co-doped biomass carbon material (NOBC-2) is synthesized through a simple hydrothermal reaction and two-step carbonization, and exhibits surprisingly high energy and long cycle life stability in the potassium ion half-cell. [Display omitted] • The preparation method of N/O co-doped biomass carbon material (NOBC-2) is simple and convenient.There are wide sources of biomass raw materials, and mass production is expected. • There are wide sources of biomass raw materials, and mass production is expected. • NOBC-2 exhibits surprisingly high energy and long cycle life in potassium ion half-cells. • Mechanism studies are designed to investigate the K+ storage behaviors. [ABSTRACT FROM AUTHOR]

Using the spore bio-carbon material as the carbon matrix, based on the surface functionalization of dopamine, the MoO 2 /N/C composite material was synthesized through simple topological chemical conversion. When applied to anode materials of potassium ion batteries, it shows amazing high energy and long cycle life stability. [Display omitted] • MoO 2 /N/C composites were fabricated on cage-like biomass charcoal by simple topological chemical transformation. • Biomass raw materials are widely available and the synthesis method is simple. • MoO 2 /N/C composites show excellent rate performance and the best long cycle stability studied at present. At the same time showing good applicability of KIB full battery. • mechanism research aims at studying the storage behavior of K+. Due to its relatively high theoretical capacity and low cost, transition metal oxides are considered as candidate anodes for potassium ion batteries (KIB). However, poor recyclability due to inherently large volume changes hinders their application. Therefore, we use Ganoderma spores as the carbon matrix to synthesize MoO 2 /N/C composites through simple complexation reactions. It was found that the synergistic effect of cage-like biomass carbon and molybdenum oxide can promote the transfer and adsorption of potassium ions, thereby improving the storage capacity of potassium ions. On the one hand, the introduction of a small amount of MoO 2 greatly enhances the potassium storage capacity of biomass carbon materials. On the other hand, the porous cage-like carbon structure effectively buffers the volume change during the MoO 2 potassium storage process and provides more diffusion paths for K+. In addition, the stable double-walled cage structure provides the possibility for the composite material to achieve good long-cycle performance. Specifically, MoO 2 /N/C composites provided a high reversible specific capacity of 422 mAh g−1 (after 200 cycles) at 200 mA g−1, and coulombic efficiency was greater than 98%. The composites still provided a high capacity of 316 mAh g−1 after 500 cycles at 500 mA g−1. At the same time, after 1500 cycles at 2000 mA g−1, the capacity was maintained at 248 mAh g−1. Verify the possibility of its practical application by assembling a full battery, meanwhile, through first-principles calculations, the reasons for the excellent potassium storage performance of MoO 2 /N/C electrodes are discussed. [ABSTRACT FROM AUTHOR]

As a high-efficiency electrocatalyst for NH 3 production via NO 2 − reduction, Mo-doped Co 3 O 4 nanoarray exhibits an extremely high Faradaic efficiency of 96.9 % and a corresponding NH 3 yield of up to 651.5 μmol/h cm−2 at −0.5 V. [Display omitted] • Mo-doped Co 3 O 4 nanoarray on titanium mesh is synthesized as an effective catalyst for NO 2 −-to-NH 3 conversion. • Mo-Co 3 O 4 /TM exhibits a high NH 3 Faradaic efficiency of 96.9 % and a related yield of 651.5 μmol h−1 cm−2 with strong stability. • DFT calculations reveal the catalytic mechanism of NO 2 −RR on Mo-Co 3 O 4. • The fabricated Zn-NO 2 − battery achieves a peak power density of 3.6 mW cm−2 and a satisfactory NH 3 yield of 108.4 μmol h−1 cm−2. Electrochemical conversion of nitrite (NO 2 −) contaminant to green ammonia (NH 3) is a promising approach to achieve the nitrogen cycle. The slow kinetics of the complex multi-reaction process remains a serious issue, and there is still a need to design highly effective and selective catalysts. Herein, we report that molybdenum doped cobalt oxide nanoarray on titanium mesh (Mo-Co 3 O 4 /TM) acts as a catalyst to facilitate electroreduction of NO 2 − to NH 3. Such a catalyst delivers an extremely high Faradaic efficiency of 96.9 % and a corresponding NH 3 yield of 651.5 μmol h−1 cm−2 at −0.5 V with strong stability. Density functional theory calculations reveal that the introduction of Mo can induce the redistribution of electrons around Co atoms and further strengthen the adsorption of NO 2 −, which is the key to facilitating the catalytic performance. Furthermore, the assembled battery based on Mo-Co 3 O 4 /TM suggests its practical application value. [ABSTRACT FROM AUTHOR]

We report on Ru-doped self-supported honeycomb nickel molybdate nanoflakes (Ru-NiMoO 4 /NF) with abundant OV on Ni foam and its application in both electrocatalytic NO 2 –RR and Zn-NO 2 – battery. The catalytic activity of Ru-NiMoO 4 /NF was significantly enhanced due to the Ru doping and the existence of oxygen vacancies, achieving high Faraday efficiency of 95.56 ± 0.72% and large ammonia yield of 17192.52 ± 1136.64 μg h−1 cm−2 at –0.6V vs. RHE in 0.5 M Na 2 SO 4 and 0.1 M NO 2 – solution, as well as preferable long-term stability. In addition, it was verified that Zn-NO 2 – battery with Ru-NiMoO 4 /NF as cathode delivers a good energy supply (13.87 mW cm−2), as well as simultaneously ammonium yield of 1524.74 μg h−1 cm−2 and Faradaic efficiency of 96.15% at 15 mA cm−2. [Display omitted] The electrocatalytic reduction of nitrite to recyclable ammonia (NH 3) is essential to maintain nitrogen balance and meet growing energy requirements. Herein, we report that Ru doped honeycomb NiMoO 4 nanosheet with copious oxygen vacancies grown on nickel foam substrate has been prepared by a facile hydrothermal synthesis and immersion process, which can act as an efficient electrocatalyst for NH 3 synthesis by reduction of nitrite. By optimizing the concentration of RuCl 3 solution, 0.01Ru-NiMoO 4 /NF possesses excellent NO 2 −RR performance with NH 3 yield of 20249.17 ± 637.42 μg h−1 cm−2 at −0.7 V and FE of 95.56 ± 0.72 % at −0.6 V. When assembled into a Zn–NO 2 − battery, it provides a remarkable level of power density of 13.89 mW cm−2, outperforming the performance of virtually all previous reports. The efficient adsorption and activation of NO 2 − over Ru-doped NiMoO 4 with oxygen vacancy have been verified by density functional theory calculations, as well as the possible reaction pathway. [ABSTRACT FROM AUTHOR]

Self-supported one-dimensional (1D) monoclinic nickel molybdate nanorods with abundant OVs on Ni foam (NiMoO 4 /NF) can achieve high Faraday efficiency of 94.49 ± 0.42% and a large ammonia yield of 18089.39 ± 227.98 μg h−1 cm−2 at –0.8V vs. RHE in 0.5 M Na 2 SO 4 and 0.1 M NO 2 – solution, together with preferable long-term stability. In addition, it was verified that Zn-NO 2 – battery with NiMoO 4 /NF as cathode delivers an ammonium yield of 1929.76 μg h−1 cm−2 and a Faradaic efficiency of 91.27% at 20 mA cm−2. [Display omitted] As an eco-friendly and sustainable strategy, the electrochemical reduction of nitrite (NO 2 –) can simultaneous generation of NH 3 and treatment of NO 2 – contamination in the environment. Herein, monoclinic NiMoO 4 nanorods with abundant oxygen vacancies self-supported on Ni foam (NiMoO 4 /NF) are considered high-performance electrocatalysts for ambient NH 3 synthesis by reduction of NO 2 −, which can deliver an outstanding yield of 18089.39 ± 227.98 μg h−1 cm−2 and a preferable FE of 94.49 ± 0.42% at −0.8 V. Additionally, its performance remains relatively stable during long-term operation as well as cycling tests. Furthermore, density functional theory calculations unveil the vital role of oxygen vacancies in promoting nitrite adsorption and activation, ensuring efficient NO 2 –RR towards NH 3. A Zn-NO 2 – battery with NiMoO 4 /NF as the cathode shows high battery performance as well. [ABSTRACT FROM AUTHOR]

Spinel-type MnCo 2 O 4 nanowire array grown on carbon cloth is highly active and stable for electrochemical NO 3 –-to-NH 3 conversion, capable of attaining a large NH 3 yield of 0.67 mmol h−1 cm−2 and the highest Faradaic efficiency of 97.1%. [Display omitted] Direct electrocatalytic reduction of nitrate (NO 3 –) is an efficient route to simultaneously synthesize ammonia (NH 3) and remove NO 3 – pollutants under ambient conditions, however, it is hindered by the lack of efficient and stable catalysts. Herein, a self-supported spinel-type MnCo 2 O 4 nanowire array is demonstrated for exclusively catalyzing the conversion of NO 3 – to NH 3 , achieving a high Faradic efficiency of 97.1% and a large NH 3 yield of 0.67 mmol h−1 cm−2. Furthermore, density functional analysis reveals that MnCo 2 O 4 (220) surface has high activity for NO 3 – reduction with a low energy barrier of 0.46 eV for *NO to *NOH. [ABSTRACT FROM AUTHOR]

Cu nanoparticles decorated juncus-derived carbon performs efficiently for electrocatalytic NH 3 production via NO 2 – reduction reaction, capable of achieving a high Faradaic efficiency of 93.2% and a large NH 3 yield of 523.5 μmol h−1 mg cat. −1. [Display omitted] Electrocatalytic nitrite reduction to value-added NH 3 can simultaneously achieve sustainable ammonia production and N -contaminant removal in natural environments, which has attracted widespread attention but still lacks efficient catalysts. In this work, Cu nanoparticles decorated juncus-derived carbon can be proposed as a high-active electrocatalyst for NO 2 −-to-NH 3 conversion, obtaining a high Faradaic efficiency of 93.2% and a satisfactory NH 3 yield of 523.5 μmol h−1 mg cat. −1. Density functional theory calculations were applied to uncover insightful understanding of internal catalytic mechanism. [ABSTRACT FROM AUTHOR]

Ag nanoarray using NiO nanosheets array on carbon cloth as support behaves as a high-active and stable electrocatalyst for NO 2 – reduction into NH 3 with a remarkably yield up to 5,751 μg h−1 cm−2 (57,510 μg h−1 mg Ag -1) and a Faradaic efficiency as high as 97.7%. Density functional theory calculations was applied to uncover its catalytic mechanism. [Display omitted] Electrochemical reduction of nitrite to ammonia can simultaneously achieve ammonia synthesis and N -contaminant removal under mild conditions, which has attracted widespread attention but still lacks efficient catalysts. In this work, Ag nanoarray using NiO nanosheets array on carbon cloth as support is reported as an efficient electrocatalyst to selectively reduce nitrite to ammonia. In 0.1 M NaOH with 0.1 M NO 2 –, such catalyst exhibits a maximum ammonia yield of 5,751 μg h−1 cm−2 (57,510 μg h−1 mg Ag -1) and high Faradaic efficiency up to 97.7 %. Density functional theory calculations applied to uncover the catalytic mechanism of NO 2 – reduction reaction on Ag. [ABSTRACT FROM AUTHOR]

Fe-doped Co 3 O 4 nanoarray on Ti mesh acts as an efficient electrocatalyst for the conversion of NO 3 − to NH 3 in 0.1 M PBS with 50 mM NO 3 −, achieving a large NH 3 yield of 0.624 mg mg cat. −1h−1 and a high Faradaic efficiency of 95.5%. Density functional theory investigations indicate favorable adsorption of NO 3 − on Fe-doped Co 3 O 4. [Display omitted] Electrochemical nitrate reduction reaction (NO 3 RR) is an attractive alternative to NH 3 production under ambient conditions. Although noble metal-based catalysts exhibit decent NO 3 RR performance to NH 3 , the high cost and insufficient supply obstruct its large-scale application. In this work, we report that Fe-doped Co 3 O 4 nanoarray efficiently catalyzes NO 3 RR for NH 3 production in neutral conditions. It achieves a large NH 3 yield of 0.624 mg mg cat. −1h−1 and high Faradaic efficiency of 95.5% at −0.7 V versus reversible hydrogen electrode. Besides, this catalyst exhibits good NO 3 RR stability. Density functional theory calculations reveal favorable adsorption of NO 3 − on Fe-doped Co 3 O 4 , which is conducive to NH 3 production in the NO 3 RR process. [ABSTRACT FROM AUTHOR]

• Fe doped Ni 3 S 2 /NF were prepared via a facile hydrothermal method. • The OER performance of Ni 3 S 2 /NF was significantly enhanced after Fe doping. • A small PDS for doped Ni 3 S 2 /NF of 0.31 eV can be obtained at the Fe site. Transition metal sulfides are one of the most efficient earth-abundant oxygen evolution reaction (OER) electrocatalysts. In the present study, Fe doped Ni 3 S 2 nanosheets have been directly grown on nickel foam via a facile hydrothermal process. The OER electrocatalytic activity of Fe-Ni 3 S 2 /NF can be enhanced by adjusting the addition amount of Fe. It requires an overpotential of 246 mV to afford a current density of 20 mA cm−2 and a Tafel slope of 66 mV dec−1, significantly lower than that of Ni 3 S 2 /NF electrode. This catalyst is highly stable, showing a slight overpotential rise of 15.1 mV over continuous testing for 20 h. In addition, combine EIS measurement and density functional theory calculations, revealing that Fe doped Ni 3 S 2 /Ni electrodes have both high conductivity and excellent intrinsic activity, leading to a promising OER electrocatalytic activity. [ABSTRACT FROM AUTHOR]

Ni 2 P nanosheet array supported on nickle foam enables ambient electrochemical NO 2 – reduction to NH 3 , achieving a large NH 3 yield rate of 2692.2 ± 92.1 μg h−1 cm−2 (3282.9 ± 112.3 μg h−1 mg cat. −1), a high Faraday efficiency of 90.2 ± 3.0%, and selectivity of 87.0 ± 1.7% at –0.3 V versus a reversible hydrogen electrode in 0.1 M phosphate buffer saline with 200 ppm NO 2 –. [Display omitted] Ammonia (NH 3) plays an important role in agriculture and industry. The industry-scale production mainly depends on the Haber-Bosch process suffering from issues of environment pollution and energy consumption. Electrochemical reduction can degrade nitrite (NO 2 –) pollutants in the environment and convert it into more valuable NH 3. Here, Ni 2 P nanosheet array on nickel foam is proposed as a 3D electrocatalyst for high-efficiency electrohydrogenation of NO 2 – to NH 3 under ambient reaction conditions. When tested in 0.1 M phosphate buffer saline with 200 ppm NO 2 –, such Ni 2 P/NF is able to obtain a large NH 3 yield rate of 2692.2 ± 92.1 μg h−1 cm−2 (3282.9 ± 112.3 μg h−1 mg cat. −1), a high Faradic efficiency of 90.2 ± 3.0%, and selectivity of 87.0 ± 1.7% at −0.3 V versus a reversible hydrogen electrode. After 10 h of electrocatalytic reduction, the conversion rate of NO 2 – achieves near 100%. The catalytic mechanism is further investigated by density functional theory calculations. [ABSTRACT FROM AUTHOR]

Electrocatalytic reduction of nitrite (NO 2 –) is an environmentally friendly method for ambient ammonia (NH 3) production, and the development of high–efficiency electrocatalysts is in urgent demand. Herein, we demonstrated that MoO 2 nanoparticles self–supported on a molybdenum plate (MoO 2 /MP) could act as an excellent catalyst for the conversion of NO 2 – to NH 3. The optimized catalyst can achieve an impressive NH 3 yield of 8678.4 ± 187.4 μg h–1 cm–2 with high Faradaic efficiency of 94.5 ± 0.2 % at −0.8 V in the solution of 0.5 M Na 2 SO 4 and 0.1 M NO 2 –, along with preferable durability. Additionally, density functional theory calculation reveals that the MoO 2 (1 ¯ 11) surface has a high activity for NO 2 – reduction, with 0.38 eV as the potential determining step (*NO 2 to NO 2 H), as well as severe suppress hydrogen evolution. [Display omitted] [ABSTRACT FROM AUTHOR]

A unique nanostructure model through surface incorporation of S and C doping on the particulate high symmetry anisotropic facets (18-facet Sr 2 CoTaO 6) double perovskite oxide semiconductor leads to significantly enhance the charge separation and boosting ionic conductivity due to facets and structural engineering resulting an enhanced photocatalytic CO 2 conversion. [Display omitted] • A unique nanostructure model through surface incorporation of S and C doping. • High symmetry anisotropic surface (Sr 2 CoTaO 6) double perovskite oxide semiconductor. • Significantly enhance the charge separation and boosting ionic conductivity. • Chemical and structural engineering resulting an enhanced photocatalytic CO 2 conversion. Perovskite semiconductor materials attracted tremendous interest in heterogeneous photocatalysis. However, most of these semiconductors have limited charge mobility and poor charge separation. Using a flux-assisted technique, we synthesized high symmetry anisotropic facets (18-facet Sr 2 CoTaO 6) double perovskite oxide semiconductor. Surface doping of sulfur (S) and carbon (C) into the lattice of a particulate novel Sr 2 CoTaO 6 induced microstrain to enhance the photocatalytic conversion of CO 2 by boosting charge density to tune charge-carrier mobility. The S and C incorporation boosted the photocatalytic CO 2 reduction more than eleven orders of magnitude higher than pristine Sr 2 CoTaO 6 under visible light irradiation. Such efficient photocatalytic CO 2 reduction is attributed to the synergistic effect of tuning the carriers mobility and spatial charge separation via chemical and electronic engineering of the particulate (S, C)-codoped Sr 2 CoTaO 6. The concept of fabrication of spatial charge separation and engineering electron mobility will explore a new avenue to design an efficient photocatalytic system for the conversion of solar energy to solar fuels. [ABSTRACT FROM AUTHOR]

Co 2 AlO 4 /CC achieves superb NO 3 − reduction performances with a large NH 3 yield of 7.9 mg h−1 cm−2 and a Faradaic efficiency of 92.6%. Furthermore, the Co 2 AlO 4 /CC-based Zn-NO 3 − battery offers a high power density and a large NH 3 yield. [Display omitted] • A Co 2 AlO 4 nanosheet array acts as a 3D electrocatalyst for NO 3 − electroreduction. • It exhibits a superior catalytic performances for selective NH 3 generation. • It attains a large NH 3 yield of 7.9 mg h−1 cm−2 and a Faradaic efficiency of 92.6%. • Zn-NO 3 − battery with Co 2 AlO 4 /CC cathode offers high power densities and NH 3 yields. • DFT reveals that Co 2 AlO 4 (2 2 0) inhibits HER but shows high NO 3 − reduction activity. A Co 2 AlO 4 nanosheet array on carbon cloth (Co 2 AlO 4 /CC) is proposed as a superb electrocatalyst for converting nitrate (NO 3 −) to ammonia (NH 3). In 0.1 M PBS solution with 0.1 M NO 3 −, it attains an NH 3 yield of 7.9 mg h−1 cm−2 with a Faradaic efficiency of 92.6%, with high durability. A Zn-NO 3 − battery with such Co 2 AlO 4 /CC as cathode offers a power density of 3.43 mW cm−2 with an NH 3 yield of 750 μg h−1 cm−2. Theoretical calculations reveal that Al ions reduce the electron cloud density on the surface of Co, making it highly conducive to NO 3 − adsorption at Co sites. Additionally, Co 2 AlO 4 (2 2 0) surface inhibits hydrogen evolution reaction but is highly active for NO 3 − reduction with a low energetically uphill pathway (ΔG of 0.42 eV) for the potential-determining step (*NO 3 to *NO 3 H), much smaller than that of Co 3 O 4 (2 2 0) (ΔG of 0.83 eV). [ABSTRACT FROM AUTHOR]

The nature of vanadium oxides with multiple valence states and a rich species of oxides facilitates the construction of high performance batteries. Among these, vanadium dioxide (VO 2), despite offering several advantages, is seldom reported in anode materials due to its inferior cycling stability and rate performance caused by large volume changes. Herein, we employed a rational structural strategy to assemble VO 2 -NTs/Ti 3 C 2 anode with a multidimensional cross-linked structure using VO 2 nanotubes (VO 2 -NTs) and Ti 3 C 2 T x MXene. Specifically, the abundant multidimensional channels of VO 2 -NTs/Ti 3 C 2 reduce the diffusion impedance of the ions, and the enhanced intrinsic conductivity and highly robust structure solve the problems originally present in VO 2 , which are verified in characterization and density functional theory calculations. Consequently, the composite electrode shows ultra-high reversible capacity (1425 mAh g−1 at 1 A g−1), excellent cycling performance (516 mAh g−1 at 5 A g−1 after 2000 cycles) and superior rate performance (703 mAh g−1 at 10 A g−1), and also exhibits decent sodium storage performance, representing the best comprehensive battery performance of VO 2 -based anodes to date. [Display omitted] • Multidimensional VO 2 -NTs/Ti 3 C 2 was successfully designed and prepared. • Optimized electronic properties and kinetics of VO 2. • Available for sodium ion and lithium ion electrochemical storage. • Troublesome capacity degradation of VO 2 during cycling conquered. [ABSTRACT FROM AUTHOR]