Shumao Cui

Crumpled Nitrogen‐Doped Graphene Nanosheets with Ultrahigh Pore Volume for High‐Performance Supercapacitor

Continuous scientifi c endeavors have been directed toward the optimization of graphene by manipulating its electronic, mechanical, chemical, and structural properties, such as surface area, pore geometry, and functional sites, in order to advance various potential applications, including nanoelectronics, energy storage/conversion, and catalysis. [ 1 ] The structural reformation of graphene, from pore generation to morphology transformation, is receiving growing attention, because the reconstruction of graphene could potentially result in localized highly reactive regions and thus unexpected properties for specifi c applications. [ 2 ] For instance, it was reported that crumpled graphene allows for the fabrication of polymer-graphene nanocomposite fi lms with low O 2 permeability and effective reduction of transparency. [ 3 ] Chemical functionalization of graphene (e.g., graphene oxide or GO) is another effective method for manipulating physical and chemical properties of graphene, because enriched reactive oxygen functional groups in GO can provide ample covalent bonding sites for the chemical functionalization. The functionalized GO can be easily converted to graphene-like materials through chemical or thermal reduction of GO. [ 4 ] For instance, nitrogen-doped graphene (NG) can be synthesized through thermal annealing of GO in ammonia, and the resulting NG showed some unique properties including improved conductivity and excellent catalytic activity. Actually, NG has been intensively investigated as electrode materials for lithium-ion batteries, catalysts for oxygen reduction reac-

Constructing 2D Porous Graphitic C3N4 Nanosheets/Nitrogen‐Doped Graphene/Layered MoS2 Ternary Nanojunction with Enhanced Photoelectrochemical Activity

A 2D porous graphitic C3 N4 nanosheets/nitrogen-doped graphene/layered MoS2 ternary nanojunction is synthesized using a simple pyrolysis process followed by a hydrothermal treatment. The 2D ternary nanojunction exhibits significantly enhanced photoelectrochemical and photocatalytic activities due to the large contact area, efficient light absorption, and rapid charge separation and transport.

Nitrogen‐Enriched Core‐Shell Structured Fe/Fe3C‐C Nanorods as Advanced Electrocatalysts for Oxygen Reduction Reaction

A cost-effective route for the preparation of Fe(3) C-based core-shell structured catalysts for oxygen reduction reactions was developed. The novel catalysts generated a much higher power density (i.e., three times higher at R(ex) of 1 Ω) than the Pt/C in microbial fuel cells. Furthermore, the N-Fe/Fe(3)C@C features an ultralow cost and excellent long-term stability suitable for mass production.

Multilayered Si Nanoparticle/Reduced Graphene Oxide Hybrid as a High‐Performance Lithium‐Ion Battery Anode

Multilayered Si/RGO anode nanostructures, featuring alternating Si nanoparticle (NP) and RGO layers, good mechanical stability, and high electrical conductivity, allow Si NPs to easily expand between RGO layers, thereby leading to high reversible capacity up to 2300 mAh g(-1) at 0.05 C (120 mA g(-1) ) and 87% capacity retention (up to 630 mAh g(-1) ) at 10 C after 152 cycles.

Ultrahigh sensitivity and layer-dependent sensing performance of phosphorene-based gas sensors.

Two-dimensional (2D) layered materials have attracted significant attention for device applications because of their unique structures and outstanding properties. Here, a field-effect transistor (FET) sensor device is fabricated based on 2D phosphorene nanosheets (PNSs). The PNS sensor exhibits an ultrahigh sensitivity to NO2 in dry air and the sensitivity is dependent on its thickness. A maximum response is observed for 4.8-nm-thick PNS, with a sensitivity up to 190% at 20 parts per billion (p.p.b.) at room temperature. First-principles calculations combined with the statistical thermodynamics modelling predict that the adsorption density is ∼1015 cm−2 for the 4.8-nm-thick PNS when exposed to 20 p.p.b. NO2 at 300 K. Our sensitivity modelling further suggests that the dependence of sensitivity on the PNS thickness is dictated by the band gap for thinner sheets (<10 nm) and by the effective thickness on gas adsorption for thicker sheets (>10 nm).

Metal Nitride/Graphene Nanohybrids: General Synthesis and Multifunctional Titanium Nitride/Graphene Electrocatalyst

A facile, efficient, and general strategy is developed for the fabrication of a new class of nanohybrids consisting of nitrogen-doped graphene functionalized with metal nitride nanoparticles. The graphene decorated with titanium nitride nanoparticles is explored for multifunctional electrocatalytic applications, i.e., as a low-cost counter electrode for I(3)(-) reduction in dye-sensitized solar cells and for nicotinamide adenine dinucleotide (NADH) oxidation in dehydrogenase enzyme-based biosensors.

Tuning gas-sensing properties of reduced graphene oxide using tin oxide nanocrystals

We report a novel and selective gas-sensing platform with reduced graphene oxide (RGO) decorated with tin oxide (SnO2) nanocrystals (NCs). This hybrid SnO2 NC–RGO platform showed enhanced NO2 but weakened NH3 sensing compared with bare RGO, showing promise in tuning the sensitivity and selectivity of RGO-based gas sensors.

Hg(II) Ion Detection Using Thermally Reduced Graphene Oxide Decorated with Functionalized Gold Nanoparticles

Fast and accurate detection of aqueous contaminants is of significant importance as these contaminants raise serious risks for human health and the environment. Mercury and its compounds are highly toxic and can cause various illnesses; however, current mercury detectors suffer from several disadvantages, such as slow response, high cost, and lack of portability. Here, we report field-effect transistor (FET) sensors based on thermally reduced graphene oxide (rGO) with thioglycolic acid (TGA) functionalized gold nanoparticles (Au NPs) (or rGO/TGA-AuNP hybrid structures) for detecting mercury(II) ions in aqueous solutions. The lowest mercury(II) ion concentration detected by the sensor is 2.5 × 10(-8) M. The drain current shows rapid response within less than 10 s after the solution containing Hg(2+) ions was added to the active area of the rGO/TGA-AuNP hybrid sensors. Our work suggests that rGO/TGA-AuNP hybrid structures are promising for low-cost, portable, real-time, heavy metal ion detectors.

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.

Strongly Coupled Ternary Hybrid Aerogels of N-deficient Porous Graphitic-C3N4 Nanosheets/N-Doped Graphene/NiFe-Layered Double Hydroxide for Solar-Driven Photoelectrochemical Water Oxidation

Developing photoanodes with efficient sunlight harvesting, excellent charge separation and transfer, and fast surface reaction kinetics remains a key challenge in photoelectrochemical water splitting devices. Here we report a new strongly coupled ternary hybrid aerogel that is designed and constructed by in situ assembly of N-deficient porous carbon nitride nanosheets and NiFe-layered double hydroxide into a 3D N-doped graphene framework architecture using a facile hydrothermal method. Such a 3D hierarchical structure combines several advantageous features, including effective light-trapping, multidimensional electron transport pathways, short charge transport time and distance, strong coupling effect, and improved surface reaction kinetics. Benefiting from the desirable nanostructure, the ternary hybrid aerogels exhibited remarkable photoelectrochemical performance for water oxidation. Results included a record-high photocurrent density that reached 162.3 μA cm(-2) at 1.4 V versus the reversible hydrogen electrode with a maximum incident photon-to-current efficiency of 2.5% at 350 nm under AM 1.5G irradiation, and remarkable photostability. The work represents a significant step toward the development of novel 3D aerogel-based photoanodes for solar water splitting.