Springtail-Inspired Superamphiphobic Ordered Nanohoodoo Arrays with Quasi-Doubly Reentrant Structures.

The skin of springtails is well-known for being able to repel water and organic liquids using their hexagonally arranged protrusions with reentrant structures. Here, a method to prepare 100 nm-sized nanohoodoo arrays with quasi-doubly reentrant structures over square centimeters through combining the nanosphere lithography and the template-protected selective reactive ion etching technique is demonstrated. The top size of the nanohoodoos, the intra-nanohoodoo distance, and the height of the nanohoodoos can be readily controlled by the plasma-etching time of the polystyrene (PS) spheres, the size of the PS spheres used, and the reactive ion etching time of silicon. The strong structural control capability allows for the study of the relationship between the nanohoodoo structure and the wetting property. Superamphiphobic nanohoodoo arrays with outstanding water/organic liquid repellent properties are finally obtained. The superamphiphobic and liquid repellent properties endow the nanohoodoo arrays with remarkable self-cleaning performance even using hot water droplets, anti-fogging performance, and the surface-enhanced Raman scattering sensitivity improvement by enriching the analyte molecules on the nanohoodoo arrays. Overall, the simple and massive production of the superamphiphobic nanohoodoo structures will push their practical application processes in diverse fields where wettability and liquid repellency need to be carefully engineered.

Active Electron Density Modulation of Co3 O4 -Based Catalysts Enhances their Oxygen Evolution Performance.

Despite the fact that many strategies have been developed to improve the efficiency of the oxygen evolution reaction (OER), the precise modulation of the surface electronic properties of catalysts to improve their catalytic activity is still challenging. Herein, we demonstrate that the surface active electron density of Co3 O4 can be effectively regulated by an argon-ion irradiation method. X-ray photoelectron and synchrotron x-ray absorption spectroscopy, UV photoelectron spectrometry, and DFT calculations show that the surface active electron density band center of Co3 O4 has been upshifted, leading to a significantly enhanced absorption capability of the oxo group. The optimized Co3 O4 -based catalysts exhibit an excellent overpotential of 260 mV at 10 mA cm-2 and Tafel slope of 54 mV dec-1 , superior to the capability of the benchmark RuO2 , representing one of the best Co-based OER catalysts. This approach could guide the future rational design and discovery of ideal electrocatalysts.

Anionic Dopant Delocalization through p-Band Modulation to Endow Metal Oxides with Enhanced Visible-Light Photoactivity.

An N-doped TiO2 model reveals a conceptually different mechanism for activating the N dopant based on delocalized orbital hybridization through O vacancy incorporation. Synchrotron-based X-ray absorption spectroscopy, time-resolved fluorescence, and DFT studies revealed that O vacancy incorporation can effectively stimulate the delocalization of N impurity states through p-band orbital modulation, which leads to a significant enhancement in photocarrier lifetime. Consequently, this effect also results in a remarkable increase in the incident photon-to-electron conversion efficiency in the range of 400-550 nm compared to that of conventional N-incorporated TiO2 (15 % versus 1 % at 450 nm). This work reveals the fundamental necessity of orbital modulation in the band engineering of metal oxides for driving solar water splitting and beyond.

Near-Infrared Light-Triggered Porous AuPd Alloy Nanoparticles To Produce Mild Localized Heat To Accelerate Bone Regeneration.

The treatment of massive bone defects is still a significant challenge for orthopedists. Here we have engineered synthetic porous AuPd alloy nanoparticles (pAuPds) as a hyperthermia agent for in situ bone regeneration through photothermal therapy (PTT). After being swallowed by cells, pAuPds produced a mild localized heat (MLH) (40-43 °C) under the irradiation of a near-infrared laser, which can greatly accelerate cell proliferation and bone regeneration. Almost 97% of the cranial defect area (8 mm in diameter) was covered by the newly formed bone after 6 weeks of PTT. RNA sequencing analysis was used to obtain insight into the molecular mechanism of the MLH on cell proliferation and bone formation. These results demonstrated that the Wnt signaling pathway was involved in the MLH. This Letter provides a unique strategy with mild heat stimulation and high efficiency for in situ bone regeneration.

Co2P Nanoparticles Wrapped in Amorphous Porous Carbon as an Efficient and Stable Catalyst for Water Oxidation.

Exploring highly active, enduringly stable, and low-cost oxygen evolution reaction catalysts continues to be a dominant challenge to commercialize renewable electrochemical water-splitting technology. High-active and earth-abundant cobalt phosphides are recently considered as promising candidates. However, the poor inherent electron transfer efficiency and instability hinder its further development. In this work, a novel approach was demonstrated to effectively synthesize Co2P nanoparticles wrapped in amorphous porous carbon framework (Co2P/C). Benefiting from extremely high specific surface area of porous carbon, plenty of active sites were adequately exposed. Meanwhile, unique anchoring structure between Co2P nanoparticles and amorphous carbon outerwear insured high charge transfer efficiency and superior stability of Co2P/C. Due to these favorable properties, low overpotential of 281 mV at 10 mA cm-2 and Tafel slope of 69 mV dec-1 were achieved in resultant Co2P/C catalyst. More significantly, it only exhibited a negligible overpotential increase after 30 h stability test, and these performances entirely preceded commercial RuO2 benchmark. In summary, we proposed a simple and feasible strategy to prepare metal phosphides wrapped with amorphous porous carbon outerwear for efficient and durable electrochemical water oxidation.