Jingchun Jia

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.

Multifunctional high-activity and robust electrocatalyst derived from metal–organic frameworks

High-activity electrocatalysts with robust structure are critical for development of renewable-energy technologies. Herein, a hybrid of cobalt nanoparticles embedded in N-doped carbon nanotubes (Co@NCNT) was fabricated via economically scalable pyrolysis of a mixture of a Co-based metal–organic framework (ZIF-67) and dicyandiamide. The as-synthesized Co@NCNT hybrid was characterized by techniques of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photon spectroscopy (XPS) etc., confirming that it possessed desirable properties of high surface area, robust structure, and good conductivity. A series of electrochemical measurements demonstrated that the Co@NCNT exhibits high activity and excellent durability toward several important electrochemical reactions, including hydrogen evolution reaction (HER) in pH-universal electrolyte, oxygen reduction reaction (ORR) in both acidic and alkaline media, glucose oxidation reaction (GOR), and oxygen evolution reaction (OER) in alkaline medium, mainly as a result of the synergistic effects of unique structure and high surface area of the Co nanoparticles and nitrogen dopant in the nanocomposite. A zinc–air battery with outstanding performance was set up using the Co@NCNT as cathode material, demonstrating its potential applications in energy storage and as a conversion system device.

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 5u2009μM–4.2u2009mM with a low detection limit (LOD) of 5.0u2009μM (S/Nu2009=u20093). 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.

Three-Dimensional Network Architecture with Hybrid Nanocarbon Composites Supporting Few-Layer MoS2 for Lithium and Sodium Storage

The exploration of anode materials for lithium ion batteries (LIBs) or sodium ion batteries (SIBs) represents a grand technological challenge to meet the continuously increased demand for the high-performance energy storage market. Here we report a facile and reliable synthetic strategy for in situ growth of few-layer MoS2 nanosheets on reduced graphene oxide (rGO) cross-linked hollow carbon spheres (HCS) with formation of three-dimensional (3D) network nanohybrids (MoS2-rGO/HCS). Systematic electrochemical studies demonstrate, as an anode of LIBs, the as-developed MoS2-rGO/HCS can deliver a reversible capacity of 1145 mAh g-1 after 100 cycles at 0.1 A g-1 and a revisible capacity of 753 mAh g-1 over 1000 cycles at 2 A g-1. For SIBs, the as-developed MoS2-rGO/HCS can also maintain a reversible capacity of 443 mAh g-1 at 1 A g-1 after 500 cycles. The excellent electrochemical performance can be attributed to the 3D porous structures, in which the few-layer MoS2 nanosheets with expanded interlayers can provide shortened ion diffusion paths and improved Li+/Na+ diffusion mobility, and the hollow porous carbon spheres and the outside graphene network are able to improve the conductivity and maintain the structural integrity.

Robust 3D macroporous structures with SnS nanoparticles decorating nitrogen-doped carbon nanosheet networks for high performance sodium-ion batteries

There still remains a great technological challenge for the development of advanced rechargeable batteries for future electric vehicles and for storage for a more renewable energy grid. In this paper a reliable and simple method for the preparation of three-dimensional (3D) hierarchical nanohybrids with tin sulfide (SnS) nanoparticles decorating nitrogen-doped carbon nanosheet networks (SnS/N-CNNs) as an anode material for SIBs is reported. The interconnected network structure, associated with its unique porous feature, endows the developed SnS/N-CNNs with enough straining space for mitigating the effect of volume expansion upon cycling, and also ensures highly favorable transport kinetics for both electrons and sodium ions. Accordingly, the SnS/N-CNNs exhibit an outstanding electrochemical performance with a high capacity and long-term cycling performance at a high mass loading, delivering high reversible capacity of 484 and 322xa0mA h g−1 at the current rate of 1.0 and 5.0 A g−1, respectively, for 1000 cycles, running at a mass loading of 1.5 mg cm−2. Capacities of 428 and 331 mA h g−1 were obtained at the current densities of 1 A g−1 at 2.8 and 4.3 mg cm−2 loading, respectively. The first principles theoretical calculations indicated that robust binding between SnS and nitrogen-doped CNNs was of great significance for maintaining the 3D network structure that achieves high capacity, high rate capability, and superior long cyclic stability even at a high mass loading.

Three-dimensional nanoarchitectures of Co nanoparticles inlayed on N-doped macroporous carbon as bifunctional electrocatalysts for glucose fuel cells

Exploring high-performance electrocatalysts is of great importance for developing clean and renewable energy conversion systems such as fuel cells and metal–air batteries. Hybrid nanostructures with transition metal nanoparticles embedded in a carbon matrix exhibit outstanding electrocatalytic activity and have emerged as promising low-cost alternatives to precious metal catalysts for a variety of electrochemical reactions. Herein, we report a convenient synthesis route to prepare a three-dimensional porous nanoarchitecture with Co nanoparticles (Co NPs) inlayed in nitrogen-doped macroporous carbon (Co/N-MC). The hybrids show an outstanding electrocatalytic activity for the oxygen reduction (ORR) and glucose oxidation reaction (GOR) due to the synergistic contribution of the Co NPs and nitrogen doping in macroporous carbon. Benefitting from their outstanding electrocatalytic activity in the ORR and GOR, a home-made glucose fuel cell (GFC) was set up using Co/N-MC as the anode and cathode material, delivering a considerable power density with decent stability.

Robust 3D network architectures of MnO nanoparticles bridged by ultrathin graphitic carbon for high-performance lithium-ion battery anodes

A strategy was developed to fabricate a set of MnO@C nanohybrids with MnO nanoparticles (NPs) embedded in an ultrathin three-dimensional (3D) carbon framework for use as anode materials for lithium-ion batteries (LIBs). The 3D carbon frameworks provide MnO NPs with electrical pathways and mechanical robustness, which efficiently improved the reaction kinetics, prevented the MnO from fracturing and agglomerating, and limited the formation of a solid electrolyte interface (SEI) at the MnO–electrolyte interface. Benefitting from the unique 3D framework structure, the MnO/C nanohybrids carbonized at 500 °C exhibited a highly reversible specific capacity of 1,420 mAh·g−1 at 0.2 A·g−1, excellent cycling stability with 98% capacity retention, and enhanced rate performance of 680 mAh·g−1 at 2 A·g−1. The feasibility of the large-scale production of such MnO/C nanohybrids, associated with their outstanding Li-ion storage properties, opens a promising avenue for the development of high-performance anodes for nextgeneration LIBs.

A self-supported Ni–Co perselenide nanorod array as a high-activity bifunctional electrode for a hydrogen-producing hydrazine fuel cell

Although the fundamental processes of electrolytic hydrogen generation are relatively well understood, fundamental studies and explorations of the new concepts and materials for electrolysis are highly desirable to make renewable hydrogen sufficiently cost-competitive. Herein, we report a proof-of-concept for an alkaline–acid-based hydrogen generating hydrazine fuel cell by coupling the hydrazine oxidation reaction (HzOR) at the alkaline anode with the hydrogen evolution reaction (HER) at the acidic cathode. Furthermore, we verified that such a hybrid cell could simultaneously fulfill hydrogen production and electricity generation owing to harvesting of two types of electrochemical energies, i.e., electrochemical energy of the HzOR and the electrochemical neutralization energy. To this end, a bifunctional electrode comprising a three-dimensional nanoporous Ni–Co perselenide nanorod array (NixCo1−xSe) was designed and prepared by a facile two-step synthesis process, involving the initial in situ electroplating on a carbon cloth followed by subsequent selenization. The optimized electrode, i.e., Ni0.5Co0.5Se2, showed high electrocatalytic activity toward HzOR in alkaline electrolyte and HER in acidic medium. The optimized alkaline–acid hydrazine fuel cell, with the Ni0.5Co0.5Se2 electrode as both the cathode and anode, could potentially deliver a power density of 13.3 mW cm−2 at a current density of 54.7 mA cm−2 with good long-term stability and a faradaic efficiency of nearly 100% for hydrogen production.