Nature nanotechnology最新文献

This Review provides a perspective on tandem catalysis schemes applied to the electrochemical reduction of carbon dioxide (CO₂). We define and classify microscopic and macroscopic site and cell tandem concepts pursued so far and provide a critical assessment and performance comparison against non-tandem systems. Our analysis demonstrates that tandem approaches generally seem to improve the selectivity for oxygenates compared with CO₂-fed copper-based or non-tandem systems. However, tandem approaches are typically inferior in terms of ethylene production compared with non-tandem approaches. The tandem electrolyser concept seems to be the most promising tandem concept owing to the reduced materials complexity and possibility of individual tuning of microenvironments for the CO-producing and CO-CO-coupling catalytic phases. We conclude our Review by addressing key remaining challenges and promising future research directions in the field of tandem CO₂ electrocatalysis.

The development of micro- and nanorobots has amplified the demand for intelligent multifunctional machines in biomedical applications, but most microrobotic systems struggle to achieve the attributes needed for those applications. Here we introduce enzymatic microbubble robots that exhibit steerable motion, enhanced biodegradability, high in vivo imaging contrast, and effective targeting and penetration of disease sites. These microrobots feature natural protein shells modified with urease to decompose bioavailable urea for autonomous propulsion, whereas an internal microbubble serves as an ultrasound imaging contrast agent for deep tissue imaging and navigation. Magnetic nanoparticle integration enables imaging-guided magnetically controlled motion and catalase functionalization facilitates chemotactic movement towards hydrogen peroxide gradients, directing robots to tumour sites. Focused ultrasound triggers robot shell collapse and inertial cavitation of the released microbubbles, creating mechanical forces that enhance therapeutic payload penetration. In vivo studies validate the tumour-targeting and therapeutic efficacy of these robots, demonstrating enhanced antitumour effects. This multifunctional microbubble robotic platform has the potential to transform medical interventions and precision therapies.

Stacking two-dimensional layered materials offers a platform to engineer electronic and magnetic states. In general, the resulting states-such as moiré magnetism-have a periodicity at the length scale of the moiré unit cell. Here we study magnetic order in twisted double-bilayer chromium triiodide by means of scanning nitrogen-vacancy microscopy. We observe long-range magnetic textures extending beyond the single moiré unit cell, which we dub a super-moiré magnetic state. At small twist angles, the size of the spontaneous magnetic texture increases with twist angle, opposite to the underlying moiré wavelength. The spin-texture size reaches a maximum of about 300 nm in 1.1° twisted devices, an order of magnitude larger than the underlying moiré wavelength, and vanishes at twist angles above 2°. The obtained magnetic field maps suggest the formation of antiferromagnetic Néel-type skyrmions spanning multiple moiré cells. The twist-angle-dependent study, combined with large-scale atomistic Monte Carlo simulations, suggests that the magnetic competition between the Dzyaloshinskii-Moriya interaction, magnetic anisotropy and exchange interactions-which all depend on the relative rotation of the layers-produces the topological textures that emerge in the super-moiré spin order.