Hetero - Atom Doped Metal-Free Carbon Nanomaterials as Potential Electrocatalyst

In recent years, hetero atom incorporated specially structured metal-free carbon nanomaterials have drawn huge attention among researchers. In comparison to the un-doped carbon nanomaterials, hetero atoms like nitrogen, sulphur, boron, phosphorous etc. incorporated nanomaterials become well-accepted as potential electrocatalysts in water splitting, supercapacitors and dye-sensitized solar cells. This review emphasizes on the mostly popular synthetic strategies utilized in last two decades and their excellent performance in electrocatalytic studies.

Bioinspired micro/nanomotor with visible light energy–dependent forward, reverse, reciprocating, and spinning schooling motion

In nature, microorganisms could sense the intensity of the incident visible light and exhibit bidirectional (positive or negative) phototaxis. However, it is still challenging to achieve the similar biomimetic phototaxis for the artificial micro/nanomotor (MNM) counterparts with the size from a few nanometers to a few micrometers. In this work, we report a fuel-free carbon nitride (C3N4)/polypyrrole nanoparticle (PPyNP)-based smart MNM operating in water, whose behavior resembles that of the phototactic microorganism. The MNM moves toward the visible light source under low illumination and away from it under high irradiation, which relies on the competitive interplay between the light-induced self-diffusiophoresis and self-thermophoresis mechanisms concurrently integrated into the MNM. Interestingly, the competition between these two mechanisms leads to a collective bidirectional phototaxis of an ensemble of MNMs under uniform illuminations and a spinning schooling behavior under a nonuniform light, both of which can be finely controllable by visible light energy. Our results provide important insights into the design of the artificial counterpart of the phototactic microorganism with sophisticated motion behaviors for diverse applications.