Three-dimensional N-doped carbon nanosheets loaded with heterostructured Ni/Ni3ZnC0.7 nanoparticles for selective and efficient CO2 reduction.

Electrocatalytic CO2 reduction (CO2RR) has emerged as a promising approach for converting CO2 into valuable chemicals and fuels to achieve a sustainable carbon cycle. However, the development of efficient electrocatalysts with high current densities and superior product selectivity remains a significant challenge. In this study, we present the synthesis of a porous nitrogen-doped carbon nanosheet loaded with heterostructured Ni/Ni3ZnC0.7 nanoparticles through a facile hydrothermal-calcination method (Ni/Ni3ZnC0.7-NC). Remarkably, the Ni/Ni3ZnC0.7-NC catalyst exhibits outstanding performance towards CO2RR in an H-cell, demonstrating a high CO faradaic efficiency of 92.47% and a current density (jCO) of 15.77 mA cm-2 at 0.87 V vs. RHE. To further explore its potential industrial applications, we constructed a flow cell and a rechargeable Zn-CO2 flow cell utilizing the Ni/Ni3ZnC0.7-NC catalyst as the cathode. Impressively, not only does the Ni/Ni3ZnC0.7-NC catalyst achieve an industrial high current density of 254 mA cm-2 at a voltage of -1.19 V vs. RHE in the flow cell, but it also exhibits a maximum power density of 4.2 mW cm-2 at 22 mA cm-2 in the Zn-CO2 flow cell, while maintaining excellent rechargeability. Density functional theory (DFT) calculations indicate that Ni/Ni3ZnC0.7-NC possesses more spontaneous reaction pathways for CO2 reduction to CO, owing to its heterogeneous structure in contrast to Ni3ZnC0.7-NC and Ni-NC. Consequently, Ni/Ni3ZnC0.7-NC demonstrates accelerated CO2RR reaction kinetics, resulting in improved catalytic activity and selectivity for CO2RR.

Hybrid Acid/Base Electrolytic Cell for Hydrogen Generation and Methanol Conversion Implemented by Bifunctional Ni/MoN Nanorod Electrocatalyst.

Combining the methanol oxidation reaction (MOR) and hydrogen evolution reaction (HER) within an integrated electrolytic system may offer the advantages of enhanced kinetics of the anode, reduced energy consumption, and the production of high-purity hydrogen. Herein, it is reported the construction of Ni─MoN nanorod arrays supported on a nickel foam substrate (Ni─MoN/NF) as a bifunctional electrocatalyst for electrocatalytic hydrogen production and selective methanol oxidation to formate. Remarkably, The optimal Ni─MoN/NF catalyst displays exceptional HER performance with an overpotential of only 49 mV to attain 10 mA cm-2 in acid, and exhibits a high activity for MOR to achieve 100 mA cm-2 at 1.48 V in alkali. A hybrid acid/base electrolytic cell with Ni─MoN/NF electrode as anode and cathode is further developed for an integrated HER-MOR cell, which only requires a voltage of 0.56 V at 10 mA cm-2 , significantly lower than that of the HER-OER system (0.70 V). The density functional theory studies reveal that the incorporation of Ni effectively modulates the electronic structure of MoN, thereby resulting in enhanced catalytic activity. The unique combination of high electrocatalytic activity and excellent stability make the Ni─MoN/NF catalyst a promising candidate for practical applications in electrocatalytic hydrogen production and methanol oxidation.

Energy-saving H2 production from a hybrid acid/alkali electrolyzer assisted by anodic glycerol oxidation.

Water electrolysis is a promising technology for efficient hydrogen production, but it has been heavily hindered by the sluggish kinetics and high potential of the anodic oxygen evolution reaction (OER). Replacing the OER with the glycerol oxidation reaction (GOR) at the anode is recognized as a potential strategy to address this issue. In this work, the self-supported electrocatalytic electrode of Cu-Cu2O nanoclusters on carbon cloth (Cu-Cu2O/CC) is fabricated for the electrocatalysis of the GOR, which has high activity towards the GOR, reaching 10 mA cm-2 at an applied voltage of 1.21 V, and shows high selectivity for formate production with a faradaic efficiency (FE) of over 80% in a wide potential range. Moreover, a hybrid acid/alkali electrolyzer is assembled by coupling the Cu-Cu2O/CC anode for the GOR in an alkaline electrolyte with commercial Pt/C as the cathode for the hydrogen evolution reaction (HER) in an acid electrolyte. The dual-electrolyte electrolytic cell only requires an applied voltage of 0.59 V to reach 10 mA cm-2 with a FE of ∼100% for H2 and 97% for formate production. This work provides a facile strategy for the application of glycerol upgradation in energy-saving water electrolysis systems.

N-Doped Carbon Nanofibers with Interweaved Nanochannels for High-Performance Sodium-Ion Storage.

Although graphite materials have been applied as commercial anodes in lithium-ion batteries (LIBs), there still remain abundant spaces in the development of carbon-based anode materials for sodium-ion batteries (SIBs). Herein, an electrospinning route is reported to fabricate nitrogen-doped carbon nanofibers with interweaved nanochannels (NCNFs-IWNC) that contain robust interconnected 1D porous channels, produced by removal of a Te nanowire template that is coelectrospun within carbon nanofibers during the electrospinning process. The NCNFs-IWNC features favorable properties, including a conductive 1D interconnected porous structure, a large specific surface area, expanded interlayer graphite-like spacing, enriched N-doped defects and active sites, toward rapid access and transport of electrolyte and electron/sodium ions. Systematic electrochemical studies indicate that the NCNFs-IWNC exhibits an impressively high rate capability, delivering a capacity of 148 mA h g-1 at current density of as high as 10 A g-1 , and has an attractively stable performance over 5000 cycles. The practical application of the as-designed NCNFs-IWNC for a full SIBs cell is further verified by coupling the NCNFs-IWNC anode with a FeFe(CN)6 cathode, which displays a desirable cycle performance, maintaining acapacity of 97 mA h g-1 over 100 cycles.

Highly dispersed ultrasmall NiS2 nanoparticles in porous carbon nanofiber anodes for sodium ion batteries.

Although sodium-ion batteries (SIBs) show attractive advantages over current dominant lithium ion batteries (LIBs), they still face great challenges in addressing the issues of low capacity and poor cycling stability. We herein report the synthesis of a nanohybrid of ultrasmall NiS2 nanoparticles embedded in porous carbon nanofibers (NiS2NP/p-CNF), which is implemented by an electrospinning process accompanied by further sulfide treatment. The highly dispersed NiS2 nanoparticles, coupled with the highly conductive porous nanofiber structure, endow the hybrids with favorable properties and structure for reducing the effects of volume expansion, providing a fast mass transport channel, and facilitating electron transfer. Systematic electrochemical studies verify that NiS2NP/p-CNF, when studied as an SIB anode, exhibits high performance with an excellent specific capacity (500 mA h g-1 at 0.1 A g-1) and a competitive rate capability, maintaining 200 mA h g-1 at 2.0 A g-1, besides a long-term stability for 1000 cycles. The NiS2NP/p-CNF nanofibers provide a huge potential for the development of massive sodium storage.

Cu3P/C Nanocomposites for Efficient Electrocatalytic CO2 Reduction and Zn-CO2 Battery.

Exploiting effective electrocatalysts toward electrochemical conversion of CO2 into valued-added chemicals is highly desirable for achieving the global carbon cycle. In this work, we report the synthesis of Cu3P/C nanocomposites by phosphatizing the copper-based metal organic framework precursor. Systematic electrochemical characterizations demonstrate the Cu3P/C nanocomposites hold high activity and favorable selectivity towards CO2 reduction reaction (CO2RR) into CO, as manifested by an onset potential is about -0.25 V versus reversible hydrogen electrode (RHE) and a faradic efficiency (FE) of 47% for CO production at a relatively low potential (-0.3 V). The attractive catalytic properties might be attributed to the synergistic effect of cooper and phosphorus elements, as well as the unique structure of Cu3P. Furthermore, we propose an asymmetrical-electrolyte Zn-CO2 battery with the Cu3P/C as cathode catalyst, demonstrating a decent performance with an open-circuit voltage of 1.5 V and a power density of 2.6 mW cm-2 (at 10 mA cm-2).

Facile Spray-Pyrolysis Synthesis of Yolk-Shell Earth-Abundant Elemental Nickel-Iron-Based Nanohybrid Electrocatalysts for Full Water Splitting.

The development of high-activity electrocatalysts for water splitting that comprise only inexpensive, earth-abundant elements is critical but remains a daunting challenge. In this work, yolk-shell Ni3 Fe/Ni3 FeN was prepared by a spray-pyrolysis technique, which could be scaleable. The yolk-shell Ni3 Fe/Ni3 FeN presents excellent catalytic activity for the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) with overpotentials of 268 and 166 mV at 10 mA cm-2 , respectively, and bears a prominent electrochemical durability. Overall water splitting with an electrolyzer containing the yolk-shell Ni3 Fe/Ni3 FeN as the cathode and anode only requires a cell voltage of 1.62 V to reach a current density of 10 mA cm-2 . The present research not only introduces a new route for the synthesis of advanced functional electrocatalysts for overall water splitting but also sheds light on their potential commercial applications.

In situ integration of CoFe alloy nanoparticles with nitrogen-doped carbon nanotubes as advanced bifunctional cathode catalysts for Zn-air batteries.

Electrochemical catalysis of O2-incorporated reactions is a promising strategy for metal-air batteries. The performance of metal-air batteries is determined by the catalytic activities of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Therefore, developing efficient catalysts with superior activities for the ORR and OER is of great significance to expand the application range of metal-air batteries. Herein, CoFe alloy nanoparticles adhered to the inside wall of nitrogen doped carbon nanotubes (CoFe@NCNTs) are synthesized and can function as a Janus particle to efficiently catalyze the ORR and OER with desirable activities in 0.1 M KOH solution. Specifically, the CoFe@NCNTs present an onset potential of 0.95 V and a half-wave potential of 0.84 V as an ORR catalyst. When used as an air-cathode catalyst for a Zn-air battery, the CoFe@NCNTs cathode performs better than a Pt/C cathode, showing a high open-circuit potential of 1.45 V, a maximum power density of 150 mW cm-2 and an average specific capacity of 808 mA h gzn-1 at current densities from 2 mA cm-2 to 10 mA cm-2.

Highly Dispersed NiO Nanoparticles Decorating graphene Nanosheets for Non-enzymatic Glucose Sensor and Biofuel Cell.

Nickel oxide-decorated graphene nanosheet (NiO/GNS), as a novel non-enzymatic electrocatalyst for glucose oxidation reaction (GOR), was synthesized through a facile hydrothermal route followed by the heat treatment. The successful synthesis of NiO/GNS was characterized by a series of techniques including XRD, BET, SEM and TEM. Significantly, the NiO/GNS catalyst show excellent catalytic activity toward GOR, and was employed to develop a sensitive non-enzymatic glucose sensor. The developed glucose sensor could response to glucose in a wide range from 5 µM-4.2 mM with a low detection limit (LOD) of 5.0 µM (S/N = 3). Importantly, compared with bare NiO, the catalytic activity of NiO/GNS was much higher. The reason might be that the 2D structure of graphene could prevent the aggregation of NiO and facilitate the electron transfer at electrode interface. Moreover, the outstanding catalytic activity of NiO/GNS was further demonstrated by applying it to construct a biofuel cell using glucose as fuel, which exhibited high stability and current density.

Lanthanum and Neodymium Doped Barium Ferrite-TiO2/MCNTs/poly(3-methyl thiophene) Composites with Nest Structures: Preparation, Characterization and Electromagnetic Microwave Absorption Properties.

We report herein the synthesis of a novel nest structured electromagnetic composite through in-situ chemical polymerization of 3-methyl thiophene (3MT) in the presence of the BaFe11.92(LaNd)0.04O19-TiO2 (BFTO) nanoparticles and MCNTs. As an absorbing material, the BFTO/MCNTs/P3MT/wax composites were prepared at various loadings of BFTO/MCNTs/P3MT (0.2:0.10:1.0 ~ 0.2:0.30:1.0), and they exhibited strong microwave absorption properties in the range of 1.0-18 GHz. When the loading of BFTO/MCNTs/P3MT is 0.2:0.30:1.0, the composite has a strongest absorbing peak at 11.04 GHz, and achieves a maximum absorbing value of -21.56 dB. The absorbing peak position moves to higher frequencies with the increase of MCNTs content. The mechanism for microwave absorption of these composites has been explained in detail.

Porous Co3O4 hollow nanododecahedra for nonenzymatic glucose biosensor and biofuel cell.

Cobalt oxide hollow nanododecahedra (Co3O4-HND) is synthesized by a facile thermal transformation of cobalt-based metal-organic framework (Co-MOF, ZIF-67) template. The morphology and properties of the Co3O4-HND are characterized by a set of techniques, including transmission electron microscope (TEM), powder X-ray diffraction (XRD), scanning electron microscope (SEM) and Brunner-Emmet-Teller (BET). When tested as a non-enzymatic electrocatalyst for glucose oxidation reaction, the Co3O4-HND exhibits a high activity and shows an outstanding performance for determining glucose with a wide window of 2.0µM to 6.06mM, a high sensitivity of 708.4µAmM(-1)cm(-2), a low detection limit of 0.58µM (S/N=3), and fast response time(<2s). Based on the nonenzymatic oxidation of glucose, Co3O4-HND could be served as an attractive non-enzyme and noble-metal-free electrocatalyst in glucose fuel cell (GFC) due to its excellent electrochemical properties, low cost and facile preparation.

One-pot synthesis of high-performance Co/graphene electrocatalysts for glucose fuel cells free of enzymes and precious metals.

A facile recipe has been developed to prepare three-dimensional nanoarchitectures of nitrogen-doped graphene loading Co nanoparticle hybrids (Co/NG). The hybrids show an outstanding electrocatalytic activity for glucose oxidation reaction (GOR) and oxygen reduction reaction (ORR), and thus can be used as electrode materials of a nonenzymatic and precious-metal-free glucose fuel cell (GFC).

Perpendicularly oriented MoSe2 /graphene nanosheets as advanced electrocatalysts for hydrogen evolution.

By increasing the density of exposed active edges, the perpendicularly oriented structure of MoSe2 nanosheets facilitates ion/electrolyte transport at the electrode interface and minimizes the restacking of nanosheets, while the graphene improves the electrical contact between the catalyst and the electrode. This makes the MoSe2 /graphene hybrid perfect as a catalyst in the hydrogen evolution reaction (HER). It shows a greatly improved catalytic activity compared with bare MoSe2 nanosheets.

A high-performance catalyst support for methanol oxidation with graphene and vanadium carbonitride.

In this study, a graphene-vanadium carbonitride (G-V(C, N)) hybrid is reported as a novel support for the Pt catalyst in methanol oxidation. The catalytic activity of the Pt/G-V(C, N) hybrid for methanol oxidation is greatly enhanced compared with that of a commercial Pt/C catalyst with carbon black as the catalyst support. The outstanding catalytic activity of the Pt/G-V(C, N) catalyst suggests the potential of using graphene-metal carbonitride as the catalyst support in fuel cells.

Hydrothermal synthesis of vanadium nitride and modulation of its catalytic performance for oxygen reduction reaction.

A creative hydrothermal synthesis method followed by calcination for vanadium nitride (VN) is reported. The oxygen reduction reaction (ORR) study of the catalyst shows that VN possesses a comparable catalytic performance to commercial Pt/C catalyst. The ORR catalytic activity study of vanadium nitride, vanadium carbonitride, and vanadium carbide reveals that tuning anions offers a promising route for the activity enhancement of the non-precious metal catalysts.

Facile one-pot, one-step synthesis of a carbon nanoarchitecture for an advanced multifunctonal electrocatalyst.

A one-pot/one-step synthesis strategy was developed for the preparation of a nitrogen-doped carbon nanoarchitecture with graphene-nanosheet growth on the inner surface of carbon nanotubes (CNTs). The N-graphene/CNT hybrids exhibit outstanding electrocatalytic activity for several important electrochemical reactions as a result of their unique morphology and defect structures, such as high but uniform nitrogen doping, graphene insertion into CNTs, considerable surface area, and the presence of iron nanoparticles. The high-yield synthetic process features high efficiency, low-cost, straightforward operation, and simple equipment.

Synthesizing nitrogen-doped activated carbon and probing its active sites for oxygen reduction reaction in microbial fuel cells.

Cost-effective cathode catalysts are critical to the development of microbial fuel cell (MFC) technology. Herein, a synthesis route is presented to improve the nitrogen content and nitrogen functionality in the nitrogen-doped activated carbon (AC) as a low cost and efficient catalyst for oxygen reduction reaction (ORR). It was demonstrated that key factors for successful nitrogen doping were the proper pretreatment with acidic and alkaline solutions consecutively and the use of a solid-state nitrogen precursor. The AC pretreated with both acidic and alkaline solutions resulted in a nitrogen content of 8.65% (atom %) (in which 5.56% is pyridinic-N) on its surface, and exhibited an outstanding electrocatalytic activity for ORR in both electrochemical and MFC tests. A good agreement between pyridinic-N content and ORR activity was observed, indicating that pyridinic-N is the most active site for ORR in the nitrogen-doped AC. The pretreated nitrogen-doped AC catalysts resulted in a higher maximum power density than the untreated AC and the commercial Pt/C (10% Pt) catalysts. The exceptional performance associated with the advantages, such as simple and convenient preparation procedure, easily obtained raw materials, and low cost, makes the pretreated nitrogen-doped AC promising for the ongoing effort to scale up MFCs.

Rational design of carbon network cross-linked Si-SiC hollow nanosphere as anode of lithium-ion batteries.

This study aims to realize controllable synthesis of Si-based nanostructures from common and easily accessible silica nanoparticles and to study their component/structure-dependent electrochemical performance as an anode of lithium-ion batteries (LIBs). To this end, a controllable route based on deliberate design has been developed to prepare hollow Si-based nanospheres with tunable composition and crystal structure at the nanoscale. The synthesis process started with coating silica nanoparticles with a carbonaceous polymer with a controllable thickness followed by magnesiothermic reduction. An Si-SiC-C composite was finally produced with a unique hollow sphere structure featuring Si-SiC nanoparticles encapsulated by a cross-linked carbon film network. In addition to the scalability of the synthetic route, the resulting composite exhibits a number of advantageous properties, including excellent electrical conductivity, highly accessible surfaces, structural coherence, and a favorable structure for the formation of a stable solid-electrolyte interphase, which makes it attractive and promising for advanced anode materials of LIBs.

Nickel oxide hollow microsphere for non-enzyme glucose detection.

A facile strategy has been developed to fabricate nickel oxide hollow microspheres (NiO-HMSs) through a solvothermal method by using a mixed solvent of ethanol and water with the assistance of sodium dodecyl sulfate (SDS). Various techniques, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), and powder X-ray diffraction (XRD), were used to characterize the morphology and the structure of as-prepared samples. It was confirmed that the products possess a hollow microsphere structure that is constructed by interconnecting porous nanoplate framework. Electrochemical studies indicate that the NiO-HMS exhibits excellent stability and high catalytic activity for electrocatalytic oxidation of glucose in alkaline solutions, which enables the NiO-HMS to be used in enzyme-free amperometric sensors for glucose determination. It was demonstrated that the NiO-HMS-based glucose biosensor offers a variety of merits, such as a wide linear response window for glucose concentrations of 1.67 µM-6.87 mM, short response time (3 s), a lower detection limit of 0.53 µM (S/N=3), high sensitivity (~2.39 mA mM(-1) cm(-2)) as well as good stability and repeatability.

CNT@TiO2 nanohybrids for high-performance anode of lithium-ion batteries.

This work describes a potential anode material for lithium-ion batteries (LIBs), namely, anatase TiO2 nanoparticle-decorated carbon nanotubes (CNTs@TiO2). The electrochemical properties of CNTs@TiO2 were thoroughly investigated using various electrochemical techniques, including cyclic voltammetry, electrochemical impedance spectroscopy, galvanostatic cycling, and rate experiments. It was revealed that compared with pure TiO2 nanoparticles and CNTs alone, the CNT@TiO2 nanohybrids offered superior rate capability and achieved better cycling performance when used as anodes of LIBs. The CNT@TiO2 nanohybrids exhibited a cycling stability with high reversible capacity of about 190 mAh g-1 after 120 cycles at a current density of 100 mA g-1 and an excellent rate capability (up to 100 mAh g-1 at a current density of 1,000 mA g-1).