Controlled Synthesis of Heterogeneous Metal–Titania Nanostructures and Their Applications

We describe a new synthetic approach to heterogeneous metal–TiO₂ nanomaterials based on conversion of Ti³⁺ to hydrous TiO₂ occurring uniquely on the nanostructured metallic surfaces such as Pt, Au, and Ni nanowires and nanoparticles. The TiO₂ growth mechanism was studied by designing an electrochemical cell. A variety of heterogeneous metal–TiO₂ nanostructures, such as segmented metal–TiO₂ nanowires, core–shell metal–TiO₂ nano/microparticles, and composite metal–TiO₂ nanotubes, can be fabricated by varying the morphology of the seeding metal nanostructure or controlling selective TiO₂ growth on different surfaces of the metallic nanomaterial. Altering the reaction time and Ti³⁺ concentration allows the TiO₂ segment lengths or TiO₂ shell thicknesses to be finely tuned. Coaxial Au–TiO₂ nanorod arrays were demonstrated to be fast lithium-ion storage materials, while the core–shell Ni–TiO₂ nanoparticles exhibited excellent photodegradation properties as magnetic recyclable photocatalysts

Progress toward Light-Harvesting Self-Electrophoretic Motors: Highly Efficient Bimetallic Nanomotors and Micropumps in Halogen Media

We have developed a highly efficient, bubble-free autonomous nanomotor based on a nanobattery. Bimetallic silver–platinum nanorods are powered by self-electrophoresis and show speeds much higher than those of other electrophoretic motors at similar fuel concentrations. The fuel (I₂) can be regenerated by exposure to ambient light, leading to renewed motion of the motor. This versatile system can also be made into a micropump that transports fluid and particles

Progress toward Light-Harvesting Self-Electrophoretic Motors: Highly Efficient Bimetallic Nanomotors and Micropumps in Halogen Media

We have developed a highly efficient, bubble-free autonomous nanomotor based on a nanobattery. Bimetallic silver–platinum nanorods are powered by self-electrophoresis and show speeds much higher than those of other electrophoretic motors at similar fuel concentrations. The fuel (I₂) can be regenerated by exposure to ambient light, leading to renewed motion of the motor. This versatile system can also be made into a micropump that transports fluid and particles

Progress toward Light-Harvesting Self-Electrophoretic Motors: Highly Efficient Bimetallic Nanomotors and Micropumps in Halogen Media

We have developed a highly efficient, bubble-free autonomous nanomotor based on a nanobattery. Bimetallic silver–platinum nanorods are powered by self-electrophoresis and show speeds much higher than those of other electrophoretic motors at similar fuel concentrations. The fuel (I₂) can be regenerated by exposure to ambient light, leading to renewed motion of the motor. This versatile system can also be made into a micropump that transports fluid and particles

Progress toward Light-Harvesting Self-Electrophoretic Motors: Highly Efficient Bimetallic Nanomotors and Micropumps in Halogen Media

We have developed a highly efficient, bubble-free autonomous nanomotor based on a nanobattery. Bimetallic silver–platinum nanorods are powered by self-electrophoresis and show speeds much higher than those of other electrophoretic motors at similar fuel concentrations. The fuel (I₂) can be regenerated by exposure to ambient light, leading to renewed motion of the motor. This versatile system can also be made into a micropump that transports fluid and particles

Progress toward Light-Harvesting Self-Electrophoretic Motors: Highly Efficient Bimetallic Nanomotors and Micropumps in Halogen Media

We have developed a highly efficient, bubble-free autonomous nanomotor based on a nanobattery. Bimetallic silver–platinum nanorods are powered by self-electrophoresis and show speeds much higher than those of other electrophoretic motors at similar fuel concentrations. The fuel (I₂) can be regenerated by exposure to ambient light, leading to renewed motion of the motor. This versatile system can also be made into a micropump that transports fluid and particles

Transition between Collective Behaviors of Micromotors in Response to Different Stimuli

We report a Ag₃PO₄ microparticle system showing collective behaviors in aqueous medium. Transition between two emergent patterns, namely “exclusion” and “schooling”, can be triggered by shift in chemical equilibrium upon the addition or removal of NH₃ or in response to UV light. The transitions are consistent with a self-diffusiophoresis mechanism resulting from ion gradients. The reported system is among the few examples of nanomotors that are based on a reversible nonredox reaction and demonstrates new design principles for micro/nanomotors. Potential applications of the reported system in logic gates, microscale pumping, and hierarchical assembly have been demonstrated

Schoenus indet.

We report a Ag₃PO₄ microparticle system showing collective behaviors in aqueous medium. Transition between two emergent patterns, namely “exclusion” and “schooling”, can be triggered by shift in chemical equilibrium upon the addition or removal of NH₃ or in response to UV light. The transitions are consistent with a self-diffusiophoresis mechanism resulting from ion gradients. The reported system is among the few examples of nanomotors that are based on a reversible nonredox reaction and demonstrates new design principles for micro/nanomotors. Potential applications of the reported system in logic gates, microscale pumping, and hierarchical assembly have been demonstrated

Transition between Collective Behaviors of Micromotors in Response to Different Stimuli

We report a Ag₃PO₄ microparticle system showing collective behaviors in aqueous medium. Transition between two emergent patterns, namely “exclusion” and “schooling”, can be triggered by shift in chemical equilibrium upon the addition or removal of NH₃ or in response to UV light. The transitions are consistent with a self-diffusiophoresis mechanism resulting from ion gradients. The reported system is among the few examples of nanomotors that are based on a reversible nonredox reaction and demonstrates new design principles for micro/nanomotors. Potential applications of the reported system in logic gates, microscale pumping, and hierarchical assembly have been demonstrated

Depolymerization-Powered Autonomous Motors Using Biocompatible Fuel

We report the design of autonomous motors powered by the rapid depolymerization reaction of poly­(2-ethyl cyanoacrylate) (PECA), an FDA-approved polymer. Motors were fabricated in two different length scales, 3 cm and 300 μm. The motion of the motors is induced by self-generated surface tension gradients along their bodies. The motors are capable of moving in various media, including salt solutions and artificial serum