A superwicking Ti-6Al-4V alloy material with a hierarchical capillary surface structure was fabricated using femtosecond laser. The basic capillary surface structure is an array of micropillars/microholes. For enhancing its capillary action, the surface of the micropillars/microholes is additionally structured by regular fine microgrooves using a technique of laser-induced periodic surface structures (LIPSS), providing an extremely strong capillary action in a temperature range between 23 °C and 80 °C. Due to strong capillary action, a water drop quickly spreads in the wicking surface structure and forms a thin film over a large surface area, resulting in fast evaporation. The maximum water flow velocity after the acceleration stage is found to be 225–250 mm/s. In contrast to other metallic materials with surface capillarity produced by laser processing, the wicking performance of which quickly degrades with time, the wicking functionality of the material created here is long-lasting. Strong and long-lasting wicking properties make the created material suitable for a large variety of practical applications based on liquid-vapor phase change. Potential significant energy savings in air-conditioning and cooling data centers due to application of the material created here can contribute to mitigation of global warming.

Capillary flow of water in an array of open nanotextured microgrooves fabricated by femtosecond laser processing of silicon is studied as a function of temperature using high-speed video recording. In a temperature range of 23–80 °C, the produced wicking material provides extremely fast liquid flow with a maximum velocity of 37 cm/s in the initial spreading stage prior to visco-inertial regime. The capillary performance of the material enhances with increasing temperature in the inertial, visco-inertial, and partially in Washburn flow regimes. The classic universal Washburn’s regime is observed at all studied temperatures, giving the evidence of its universality at high temperatures as well. The obtained results are of great significance for creating capillary materials for applications in cooling of electronics, energy harvesting, enhancing the critical heat flux of industrial boilers, and Maisotsenko cycle technologies.

Methods of seawater desalination and carbon dioxide (CO₂) reduction using clean and renewable energy have attracted much attention withing the reducing fresh water and growing CO₂ concentration. Here, we propose a synergistic method for solar-driven desalination and CO₂ reduction at the surface of sea using a three-dimensional titanium oxide-gold semiconductor/metal (TiO₂-Au NW/NPs (NW: nanowire, NP: nanoparticle)) photothermal conversion membrane that can efficiently harvest a broad solar spectrum (200 to 2500 nm, 94%) to undertake the conversion of light-to-heat and light-to-electricity. The TiO₂-Au NW/NPs membrane demonstrated a high solar vapor conversion efficiency of ∼ 90%, CO₂ reduction yields of 0.066 µmol·cm² CH₄ and 0.015 µmol·cm⁻² CO within 5 h. In addition, the membrane efficiently evaporated seawater with different salt concentrations to produce drinking water which meet World Health Organization (WHO) and US Environmental Protection Agency (EPA) standards. This work provides an integrated solution for solar desalination and CO₂ reduction at the surface of sea to reduce the harm to marine life caused by ocean acidification while producing pure water.

Realizing the anisotropic deep trenching of GaN without surface damage is essential for the fabrication of GaN-based devices. However, traditional dry etching technologies introduce irreversible damage to GaN and degrade the performance of the device. In this paper, we demonstrate a damage-free, rapid metal-assisted chemical etching (MacEtch) method and perform an anisotropic, deep trenching of a GaN array. Regular GaN microarrays are fabricated based on the proposed method, in which CuSO₄ and HF are adopted as etchants while ultraviolet light and Ni/Ag mask are applied to catalyze the etching process of GaN, reaching an etching rate of 100 nm/min. We comprehensively explore the etching mechanism by adopting three different patterns, comparing a Ni/Ag mask with a SiN mask, and adjusting the etchant proportion. Under the catalytic role of Ni/Ag, the GaN etching rate nearby the metal mask is much faster than that of other parts, which contributes to the formation of deep trenches. Furthermore, an optimized etchant is studied to restrain the disorder accumulation of excessive Cu particles and guarantee a continuous etching result. Notably, our work presents a novel low-cost MacEtch method to achieve GaN deep etching at room temperature, which may promote the evolution of GaN-based device fabrication.

Lithium–carbon dioxide (Li-CO₂) batteries have attracted considerable attention due to their high theoretical energy densities and potential for capturing and converting CO₂ toward net-zero carbon dioxide emissions. However, the reversible cycling capability of Li-CO₂ batteries is greatly limited by the sluggish kinetics of the CO₂ evolution reaction (CO₂ER), which leads to excessive charge voltages exceeding 4.0 V, thus significantly hindering the practical advancement of the battery technology. Herein, we report dual-active-site AuRu catalysts supported on TiO₂ nanorod arrays, grown on carbon nanofiber, where TiO₂ layers effectively prevent carbon corrosion and the electronic synergy of the dual active site design comprising Au and Ru can lower the reaction energy barriers of the CO₂RR and CO₂ER. Calculation results reveal that this synergy gives rise to complementary catalytic roles: Au facilitates CO₂ activation, whereas Ru promotes Li₂CO₃ breakdown, collectively enhancing the overall reaction kinetics. Consequently, Li-CO₂ batteries employing AuRu/TiO₂ cathode deliver an ultralong cycle life exceeding 1100 cycles (~2200 h), low charge voltages (2.9-3.1 V), high energy efficiency (~77.9%), and excellent stability at elevated temperatures. This work establishes a generalizable catalyst-support strategy for long lifespan metal-CO₂ batteries, offering a promising route toward high-performance carbon neutral energy storage devices