Etching-Free Ultrafast Fabrication of Self-Rolled Metallic Nanosheets with Controllable Twisting

Ultra-Efficient and Cost-Effective Platinum Nanomembrane Electrocatalyst for Sustainable Hydrogen Production

Hydrogen production through hydrogen evolution reaction (HER) offers a promising solution to combat climate change by replacing fossil fuels with clean energy sources. However, the widespread adoption of efficient electrocatalysts, such as platinum (Pt), has been hindered by their high cost. In this study, we developed an easy-to-implement method to create ultrathin Pt nanomembranes, which catalyze HER at a cost significantly lower than commercial Pt/C and comparable to non-noble metal electrocatalysts. These Pt nanomembranes consist of highly distorted Pt nanocrystals and exhibit a heterogeneous elastic strain field, a characteristic rarely seen in conventional crystals. This unique feature results in significantly higher electrocatalytic efficiency than various forms of Pt electrocatalysts, including Pt/C, Pt foils, and numerous Pt single-atom or single-cluster catalysts. Our research offers a promising approach to develop highly efficient and cost-effective low-dimensional electrocatalysts for sustainable hydrogen production, potentially addressing the challenges posed by the climate crisis.

3D Chiral Micro-Pinwheels Based on Rolling-Up Kirigami Technology

Expanding micro-/nanostructures into 3D ones results not only in boosting structural integration level with compact geometry but also enhancing a device's complexity and functionality. Herein, a synergetic 3D micro-/nanoshape transformation is proposed by combining kirigami and rolling-up techniques, or rolling-up kirigami, for the first time. As an example, micro-pinwheels with multiple flabella are patterned on pre-stressed bilayer membranes and rolled up into 3D structures. The flabella are designed when they are patterned on a 2D thin film, facilitating the integration of micro-/nanoelement and other functionalization processes during 2D patterning, which is typically much easier than post-shaping an as-fabricated 3D structure by removing redundant materials or 3D printing. The dynamic rolling-up process is simulated using elastic mechanics with a movable releasing boundary. Mutual competition and cooperation among flabella are observed during the whole release process. More importantly, the mutual conversion between translation and rotation offers a reliable platform for developing parallel microrobots and adaptive 3D micro-antennas. Additionally, 3D chiral micro-pinwheel arrays integrated into a microfluidic chip are successfully applied to detect organic molecules in solution using a terahertz apparatus. With an extra actuation, active micro-pinwheels can potentially serve as a base to functionalize 3D kirigami as tunable devices.