Lei Guo

Bio: Lei Guo is an academic researcher from Qingdao University. The author has contributed to research in topics: Nanomaterials & Materials science. The author has an hindex of 4, co-authored 10 publications receiving 80 citations.

Synthesis of Three-Dimensional Graphene-Based Hybrid Materials for Water Purification: A Review

Abstract: Graphene-based nanostructures and nanomaterials have been widely used for the applications in materials science, biomedicine, tissue engineering, sensors, energy, catalysis, and environmental science due to their unique physical, chemical, and electronic properties. Compared to two-dimensional (2D) graphene materials, three-dimensional (3D) graphene-based hybrid materials (GBHMs) exhibited higher surface area and special porous structure, making them excellent candidates for practical applications in water purification. In this work, we present recent advances in the synthesis and water remediation applications of 3D GBHMs. More details on the synthesis strategies of GBHMs, the water treatment techniques, and the adsorption/removal of various pollutants from water systems with GBHMs are demonstrated and discussed. It is expected that this work will attract wide interests on the structural design and facile synthesis of novel 3D GBHMs, and promote the advanced applications of 3D GBHMs in energy and environmental fields.

Carbon nanofiber-based three-dimensional nanomaterials for energy and environmental applications

Abstract: Carbon nanofibers (CNFs) not only retain a similar one-dimensional nanostructure, similar special properties, and similar multi-functionality to carbon nanotubes, but they also exhibit a few advantages, like easier production, lower cost, lower crystallinity, and more defects. Therefore, CNF-based nanomaterials have been widely used for applications relating to energy conversion/storage, catalysis, sensors, adsorption/separation, and biomedical engineering. Due to their high specific surface area, interconnected porous structure, light weight, and high mechanical strength, CNF-based three-dimensional (3D) nanomaterials have attracted more and more attention in many fields, especially in energy production/storage and environmental science. In this work, we demonstrate the development of CNF-based 3D nanomaterials for applications relating to energy and environmental science. To achieve this aim, typical design strategies for the production of CNF-based 3D nanomaterials, including electrospinning, chemical vapor deposition, templated synthesis, hydrothermal synthesis, and other combined techniques are introduced and summarized, and then cases involving fabricated CNF 3D nanomaterials for supercapacitors, fuel cells, electrochemical batteries, water purification, air cleaning, and microwave/radiation adsorption are presented and discussed. This study will be helpful for readers to understand the production of CNFs, and the subsequent design and fabrication of functional CNF-based 3D nanostructures and nanomaterials; meanwhile it will be valuable for promoting the advanced applications of CNF-based nanomaterials in different fields.

Biomimetic two-dimensional nanozymes: synthesis, hybridization, functional tailoring, and biosensor applications

Abstract: Biological enzymes play important roles in mediating the biological reactions in vitro and in vivo due to their high catalytic activity, strong bioactivity, and high specificity; however, they have also some disadvantages such as high cost, low environmental stability, weak reusability, and difficult production. To overcome these shortcomings, functional nanomaterials including metallic nanoparticles, single atoms, metal oxides, alloys, and others have been utilized as nanozymes to mimic the properties and functions of natural enzymes. Due to the development of the synthesis and applications of two-dimensional (2D) materials, 2D nanomaterials have shown high potential to be used as novel nanozymes in biosensing, bioimaging, therapy, logic gates, and environmental remediation due to their unique physical, chemical, biological, and electronic properties. In this work, we summarize recent advances in the preparation and functionalization, as well as biosensor and immunoassay applications of various 2D material-based nanozymes. To achieve this aim, first we demonstrate the preparation strategies of 2D nanozymes such as chemical reduction, templated synthesis, chemical exfoliation, calcination, electrochemical deposition, hydrothermal synthesis, and many others. Meanwhile, the structure and properties of the 2D nanozymes prepared by conjugating 2D materials with nanoparticles, metal oxides, biomolecules, polymers, ions, and 2D heteromaterials are introduced and discussed in detail. Then, the applications of the prepared 2D nanozymes in colorimetric, electrochemical, fluorescent, and electrochemiluminescent sensors are demonstrated.

The Combination of Two-Dimensional Nanomaterials with Metal Oxide Nanoparticles for Gas Sensors: A Review

Abstract: Metal oxide nanoparticles have been widely utilized for the fabrication of functional gas sensors to determine various flammable, explosive, toxic, and harmful gases due to their advantages of low cost, fast response, and high sensitivity. However, metal oxide-based gas sensors reveal the shortcomings of high operating temperature, high power requirement, and low selectivity, which limited their rapid development in the fabrication of high-performance gas sensors. The combination of metal oxides with two-dimensional (2D) nanomaterials to construct a heterostructure can hybridize the advantages of each other and overcome their respective shortcomings, thereby improving the sensing performance of the fabricated gas sensors. In this review, we present recent advances in the fabrication of metal oxide-, 2D nanomaterials-, as well as 2D material/metal oxide composite-based gas sensors with highly sensitive and selective functions. To achieve this aim, we firstly introduce the working principles of various gas sensors, and then discuss the factors that could affect the sensitivity of gas sensors. After that, a lot of cases on the fabrication of gas sensors by using metal oxides, 2D materials, and 2D material/metal oxide composites are demonstrated. Finally, we summarize the current development and discuss potential research directions in this promising topic. We believe in this work is helpful for the readers in multidiscipline research fields like materials science, nanotechnology, chemical engineering, environmental science, and other related aspects.