Publications

A one-dimensional displacement and speed sensing technology that consists of a pair of micro-grating structures and utilizes the coupling between the triboelectric effect and electrostatic induction is demonstrated. Its distinct advantages, including being self-powered, high resolution, large dynamic range, and long detecting distance, show extensive potential applications in automation, manufacturing, process control, and portable devices.

Abstract Sustainable, clean, random energy resources from the environment, like that from ubiquitous human biomechanical movements, are highly desirable for the information era. Such biomechanical energy can be captured via textile triboelectric nanogenerators (TENGs). However, realizing a textile TENG that has a self‐driven working mode, dynamic pattern designability, high electrical performance, mechanical robustness, and industrialized fabrication is challenging because of the difficulty in fancy‐yarn structure manipulation. Here, for the first time, a 3D braided stretchable hierarchical interlocking fancy‐yarn TENG (3D HIFY‐TENG) with deoxyribonucleic acid‐like double‐wing spiral structure is industrially exploited for multifunctional energy harvesting modes and self‐powered biomechanical sensing. The 3D HIFY‐TENG can generate self‐driven triboelectrical outputs without relying on other objects by body movements. It shows a mechanical robustness (6.9 cN dtex −1 ), excellent stretchability (>350%), weavability, washability and human‐body comfort. Moreover, geometric and mechanical behavior of the 3D HIFY‐TENG are systematically investigated theoretically and experimentally. Further, multifunctional 3D HIFY‐TENG fabrics are explored, which can not only harvest biomechanical energy and monitor body movement, but exhibit a unique adjustable pore effect, providing potential for dynamic electronic textile pattern design. In addition, a smart fitness system is developed for exercise management of real‐time exercise detection, frequency analysis, and self‐powered posture correction alarms.

As one of the major air pollutants, NOX is rather challenging to remove. The main treatment method is catalytic reduction with plenty of reducing agents, which lacks any effective control in an open air environment such as urban spaces. It is necessary to seek a self-powered electrochemical process for environmental treatment. The triboelectric nanogenerator (TENG), a developing technology with various advantages, is widely used in energy and environmental monitoring and cleaning. In this work, a radial-engine-shaped TENG system with five stacked TENGs is designed to synchronously absorb NOX and degrade its main enrichment forms of nitrate and nitrite in aqueous solution. In addition, the system possesses inherent phase differences and outputs continuous direct current after rectification. Moreover, we demonstrated that, driven by artificial wind at a speed of 6 m/s, the NOX generated by a chemical method was effectively degraded by the radial-engine-shaped TENG system.

Aggregation of nanoparticles impacts their reactivity, stability, transport, and fate in aqueous environments, but limited methods are available to characterize structural features and movement of aggregates in liquid. Here, liquid cell transmission electron microscopy (LCTEM) was utilized to directly observe the size, morphology, and motion of aggregates that were composed of 9 and 36 nm hematite nanoparticles, respectively, in water or NaCl solution. When mass concentrations were same, the aggregates of 9 nm nanoparticles were statistically more compact and slightly larger than those of 36 nm nanoparticles. Aggregates in both samples were typically nonspherical. Increasing ionic strength resulted in larger aggregates, and also enhanced the stability of aggregates under electron-beam irradiation. In water, small aggregates moved randomly and approached repeatedly to large aggregates before final attachment. In NaCl solution, small aggregates moved directly toward large aggregates and attached to the latter quickly. This observation provided a direct confirmation of the DLVO theory that the energy barrier to aggregation is higher in water than in salt solutions. This study not only presented the influences of particle size and ionic strength on aggregation state, but also demonstrated that LCTEM is a promising method to link aggregation state to dynamic processes of nanoparticles.

'Plasmon Resonance Energy Transfer from Metallic Nanoparticles to Biomolecules' published in 'Encyclopedia of Nanotechnology'

We report a facile synthesis of monodisperse core/shell 5/1.5 nm Au/CuPt nanoparticles by coreduction of platinum acetylacetonate and copper acetylacetonate in the presence of 5 nm Au nanoparticles. The CuPt alloy effect and core/shell interactions make these Au/CuPt nanoparticles a promising catalyst for both oxygen reduction reaction and methanol oxidation reaction in 0.1 M HClO4 solution. Their specific (mass) reduction and oxidation activities reach 2.72 mA/cm(2) (1500 mA/mg Pt) at 0.9 V and 0.755 mA/cm(2) (441 mA/mg Pt) at 0.8 V (vs reversible hydrogen electrode), respectively. Our studies show that the existence of the Au nanoparticle core not only minimizes the Pt usage but also improves the stability of the Au/CuPt catalyst for fuel cell reactions. The results suggest that the core/shell design is indeed effective for optimizing nanoparticle catalysis. The same concept may be extended to other multimetallic nanoparticle systems, making it possible to tune nanoparticle catalysis for many different chemical reactions.