Piezocatalysis has gradually come into the limelight due to its great potential for solving energy shortages and environmental pollution problems. However, limited piezocatalytic efficiency is a severe bottleneck for its practical applications. Here, well-defined BaTiO 3 nanosheets with highly exposed {001} polar facets are successfully synthesized to enhance the piezocatalytic activity. The [001] piezoelectric polarization can drive the carriers to migrate to the surface along the out-of-plane direction. The polar surface provides abundant active sites for the piezocatalytic reaction. As a result, a superior piezocatalytic degradation ratio of organic pollutants is obtained with a high first-order rate constant k of 0.0835 min −1 , which is 2.7 times higher than the BaTiO 3 nanoparticles. Furthermore, BaTiO 3 nanosheets display an outstanding H 2 production capability, with the rate of 305 µmol g −1 h -1 , which is almost two times higher than that of BaTiO 3 nanoparticles. This work thus provides a novel and comprehensive strategy for designing high-performance piezocatalysts with an out-of-plane polarization, and also provides novel insights for the optimization of the piezocatalytic activity by regulating the polar facet of piezocatalysts.

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Microfluidic devices offer important benefits for forensic applications, in particular for fast tests at a crime scene. A large portion of forensic applications require microfluidic chip material to show compatibility with biochemical reactions (such as amplification reactions), and to have high transparency in the visible region and high chemical resistance. Also, preferably, manufacturing should be simple. The characteristic properties of cyclic olefin copolymer (COC) fulfills these requirements and offers new opportunities for the development of new forensic tests. In this work, the versatility of COC as material for lab-on-a-chip (LOC) systems in forensic applications has been explored by realizing two proof-of-principle devices. Chemical resistance and optical transparency were investigated for the development of an on-chip presumptive color test to indicate the presence of an illicit substance through applying absorption spectroscopy. Furthermore, the compatibility of COC with a DNA amplification reaction was verified by performing an on-chip multiple displacement amplification (MDA) reaction.

Magnetic fields have been regarded as an additional stimulus for electro‐ and photocatalytic reactions, but not as a direct trigger for catalytic processes. Multiferroic/magnetoelectric materials, whose electrical polarization and surface charges can be magnetically altered, are especially suitable for triggering and control of catalytic reactions solely with magnetic fields. Here, it is demonstrated that magnetic fields can be employed as an independent input energy source for hydrogen harvesting by means of the magnetoelectric effect. Composite multiferroic CoFe2O4–BiFeO3 core–shell nanoparticles act as catalysts for the hydrogen evolution reaction (HER), which is triggered when an alternating magnetic field is applied to an aqueous dispersion of the magnetoelectric nanocatalysts. Based on density functional calculations, it is proposed that the hydrogen evolution is driven by changes in the ferroelectric polarization direction of BiFeO3 caused by the magnetoelectric coupling. It is believed that the findings will open new avenues toward magnetically induced renewable energy harvesting.

Wireless small-scale robots hold great promise for diagnosis and treatment of certain diseases and/or pathologies in a minimally invasive way. [1] These mobile systems are engineered to