Fei Liu

Bio: Fei Liu is an academic researcher from Iowa State University. The author has contributed to research in topics: Medicine & Nanoparticle. The author has an hindex of 27, co-authored 60 publications receiving 3599 citations. Previous affiliations of Fei Liu include University of Texas at Austin & Zhejiang University.

Synthesis of Phosphorus-Doped Graphene and its Multifunctional Applications for Oxygen Reduction Reaction and Lithium Ion Batteries

Abstract: We develop a simple and economical thermal annealing method for the synthesis of phosphorus-doped graphene, which exhibits remarkable electrocatalytic activity towards the oxygen reduction reaction and enhances the electrochemical performance as an anode material for lithium ion batteries. The experimental results suggest the significant role of phosphorus atoms in graphene.

Hybrid of Iron Nitride and Nitrogen‐Doped Graphene Aerogel as Synergistic Catalyst for Oxygen Reduction Reaction

Abstract: It is extremely desirable but challenging to create highly active, stable, and low-cost catalysts towards oxygen reduction reaction to replace Pt-based catalysts in order to perform the commercialization of fuel cells Here, a novel iron nitride/nitrogen doped-graphene aerogel hybrid, synthesized by a facile two-step hydrothermal process, in which iron phthalocyanine is uniformly dispersed and anchored on graphene surface with the assist of π–π stacking and oxygen-containing functional groups, is reported As a result, there exist strong interactions between Fe x N nanoparticles and graphene substrates, leading to a synergistic effect towards oxygen reduction reaction It is worth noting that the onset potential and current density of the hybrid are significantly better and the charge transfer resistance is much lower than that of pure nitrogen-doped graphene aerogel, free Fe x N and their physical mixtures The hybrid also exhibits comparable catalytic activity as commercial Pt/C at the same catalyst loading, while its stability and resistance to methanol crossover are superior Interestingly, it is found that, apart from the active nature of the hybrid, the large surface area and porosity are responsible for its excellent onset potential and the high density of Fe–N–C sties and small size of Fe x N particles boost charge transfer rate

Multifunctional Co3S4/graphene composites for lithium ion batteries and oxygen reduction reaction.

Abstract: Cobalt sulfide is a good candidate for both lithium ion batteries (LIBs) and cathodic oxygen reduction reaction (ORR), but low conductivity, poor cyclability, capacity fading, and structural changes hinder its applications. The incorporation of graphene into CO 3 S 4 makes it a promising electrode by providing better electrochemical coupling, enhanced conductivity, fast mobility of ions and electrons, and a stabilized structure due to its elastic nature. With the objective of achieving high-performance composites, herein we report a facile hydrothermal process for growing CO 3 S 4 nanotubes (NTs) on graphene (G) sheets. Electrochemical impedance spectroscopy (EIS) verified that graphene dramatically increases the conductivity of the composites to almost twice that of pristine CO 3 S 4 . Electrochemical measurements indicated that the as-synthesized CO 3 S 4 / G composites exhibit good cyclic stability and a high discharge capacity of 720 mAhg1 up to 100 cycles with 99.9% coulombic efficiency. Furthermore, the composites react with dissolved oxygen in the ORR by fourand two-electron mechanisms in both acidic and basic media with an onset potential close to that of commercial Pt/C. The stability of the composites is much higher than that of Pt/C, and exhibit high methanol tolerance. Thus, these properties endorse CO 3 S 4 /G composites as auspicious candidates for both LIBs and ORR.

Hybrid of Co3Sn2@Co Nanoparticles and Nitrogen-Doped Graphene as a Lithium Ion Battery Anode

Abstract: A facile strategy was designed for the fabrication of hybrid of Co3Sn2@Co nanoparticles (NPs) and nitrogen-doped graphene (NG) sheets through a hydrothermal synthesis, followed by annealing process. Core–shell architecture of Co3Sn2@Co pin on NG is designed for the dual encapsulation of Co3Sn2 with adaptable ensembles of Co and NG to address the structural and interfacial stability concerns facing tin-based anodes. In the resulted unique architecture of Co3Sn2@Co–NG hybrid, the sealed cobalt cover prevents the direct exposer of Sn with electrolyte because of encapsulated structure and keeps the structural and interfacial integrity of Co3Sn2. However, the elastically strong, flexible and conductive NG overcoat accommodates the volume changes and therefore brings the structural and electrical stabilization of Co3Sn2@Co NPs. As a result, Co3Sn2@Co–NG hybrid exhibits extraordinary reversible capacity of 1615 mAh/g at 250 mA/g after 100 cycles with excellent capacity retention of 102%. The hybrid bears superio...

Recent Advances in Ultrathin Two-Dimensional Nanomaterials

Abstract: Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocat...

Noncovalent Functionalization of Graphene and Graphene Oxide for Energy Materials, Biosensing, Catalytic, and Biomedical Applications

Abstract: This Review focuses on noncovalent functionalization of graphene and graphene oxide with various species involving biomolecules, polymers, drugs, metals and metal oxide-based nanoparticles, quantum dots, magnetic nanostructures, other carbon allotropes (fullerenes, nanodiamonds, and carbon nanotubes), and graphene analogues (MoS2, WS2). A brief description of π–π interactions, van der Waals forces, ionic interactions, and hydrogen bonding allowing noncovalent modification of graphene and graphene oxide is first given. The main part of this Review is devoted to tailored functionalization for applications in drug delivery, energy materials, solar cells, water splitting, biosensing, bioimaging, environmental, catalytic, photocatalytic, and biomedical technologies. A significant part of this Review explores the possibilities of graphene/graphene oxide-based 3D superstructures and their use in lithium-ion batteries. This Review ends with a look at challenges and future prospects of noncovalently modified graph...

Heteroatom-doped graphene materials: syntheses, properties and applications

Abstract: Heteroatom doping can endow graphene with various new or improved electromagnetic, physicochemical, optical, and structural properties. This greatly extends the arsenal of graphene materials and their potential for a spectrum of applications. Considering the latest developments, we comprehensively and critically discuss the syntheses, properties and emerging applications of the growing family of heteroatom-doped graphene materials. The advantages, disadvantages, and preferential doping features of current synthesis approaches are compared, aiming to provide clues for developing new and controllable synthetic routes. We emphasize the distinct properties resulting from various dopants, different doping levels and configurations, and synergistic effects from co-dopants, hoping to assist a better understanding of doped graphene materials. The mechanisms underlying their advantageous uses for energy storage, energy conversion, sensing, and gas storage are highlighted, aiming to stimulate more competent applications.