A Pd nanoparticle‐containing polymer microsphere moves with increasing speed across a pH gradient, following differential catalytic decomposition of aqueous hydrogen peroxide. The directional motion is akin to the pH taxis of living microorganisms. The artificial pH taxis exhibits random walk, translation, vertical, hopping, and pulsed motion, when the size of the motor and the imposed pH gradient are modulated.

Broken inversion symmetry in atomic structure can lead to the emergence of specific functionalities at the nanoscale. Therefore, realizing 2D materials in Janus form is a growing field, which offers unique features and opportunities. In this paper, we investigate the structural, vibrational, elastic, piezoelectric, and electronic properties of Janus BiXY (X = S, Se, Te and Y = F, Cl, Br, I) monolayers based on first-principle methods. The structural optimization and vibrational frequency analysis reveal that all of the proposed structures are dynamically stable. Additionally, ab initio molecular dynamics simulations verify the thermal stability of these structures even at elevated temperatures. The mechanical response of the Janus BiXY crystals in the elastic regime is investigated in terms of in-plane stiffness and the Poisson ratio, and the obtained results ascertain their mechanical flexibility. The piezoelectric stress and strain coefficient analysis demonstrates the appearance of strong out-of-plane piezoelectricity, which is comparable with the Janus transition metal dichalcogenide monolayers. The calculated electronic band structures reveal that except for BiTeF, all Janus BiXY monolayers are indirect band gap semiconductors, and their energy band gaps span from the infrared to the visible part of the optical spectrum. Subsequently, large Rashba spin splitting is observed in electronic band structures when the spin-orbit coupling is included. The obtained results point out Janus 2D BiXY structures as promising materials for a wide range of applications in nanoscale piezoelectric and spintronics fields.

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The physical properties of the single-crystalline samples of Lu2Ir3Si5 have been investigated by magnetic susceptibility, resistivity and heat capacity studies. We observed multiple charge density wave (CDW) transitions in all the measurements. A strong thermal hysteresis at these transitions suggests a possible first order CDW ordering. In addition, the first order nature is ascertained by a very narrow and a huge cusp (62 J/mol K) in the zero field specific heat data which also suggests a strong interchain coupling. By applying a field of 9T in the specific heat measurement, one of the CDW transitions is suppressed.

In this letter, we report the development of a polymer-based chemical locomotive. Pd nanoparticle coated polymer resin beads were used for catalytic decomposition of H2O2 in aqueous medium. The oxygen bubbles generated in this way stuck to the beads after their formation. When there were sufficient numbers of bubbles formed or when the bubbles were large, vertical movement of the bead with constant velocity could be observed. The velocity could be as much as 0.59 cm s-1 at the highest H2O2 concentration used. Further, the vertical velocity could systematically be controlled by changing the viscosity of the medium (by addition of glycerol). We observed that the velocity was inversely proportional to the viscosity of the medium. Appropriate theoretical analysis has also been reported. Once the vertical velocity was zero, horizontal motion and rotational motion could be observed. Further, a collection of such beads was used to propel large macroscopic objects providing linear and rotational motions.