Zhenwei Yu

A novel reusable superhydrophilic NiO/Ni mesh produced by a facile fabrication method for superior oil/water separation

There is a critical need to develop durable and reusable materials for oil–water separation, especially in harsh environments. Traditional anti-fouling mesh-based separation technologies are not reusable and limited by poor temperature resistance. Here we report a novel superhydrophilic and underwater superoleophobic NiO/Ni mesh which shows superior oil/water separation in harsh environments, with reusable and durable properties that can separate different oil–water mixtures with and without sand and soil contaminants, a >99% separation efficiency and up to 5.4 × 104 L m−2 h−1 permeate flux. The material is able to retain its superior performance over the 20 cycles we measured and for mixtures of sticky oils its performance is easily recoverable after a quick heat treatment. Our separation methodology is solely gravity-driven and consequently is expected to be highly energy-efficient. We anticipate that our separation methodology will have numerous applications, including in the clean-up of oil spills, wastewater treatment and other harsh condition oil–water separations.

Desert Beetle-Inspired Superwettable Patterned Surfaces for Water Harvesting

With the impacts of climate change and impending crisis of clean drinking water, designing functional materials for water harvesting from fog with large water capacity has received much attention in recent years. Nature has evolved different strategies for surviving dry, arid, and xeric conditions. Nature is a school for human beings. In this contribution, inspired by the Stenocara beetle, superhydrophilic/superhydrophobic patterned surfaces are fabricated on the silica poly(dimethylsiloxane) (PDMS)-coated superhydrophobic surfaces using a pulsed laser deposition approach with masks. The resultant samples with patterned wettability demonstrate water-harvesting efficiency in comparison with the silica PDMS-coated superhydrophobic surface and the Pt nanoparticles-coated superhydrophilic surface. The maximum water-harvesting efficiency can reach about 5.3 g cm-2 h-1 . Both the size and the percentage of the Pt-coated superhydrophilic square regions on the patterned surface affect the condensation and coalescence of the water droplet, as well as the final water-harvesting efficiency. The present water-harvesting strategy should provide an avenue to alleviate the water crisis facing mankind in certain arid regions of the world.

A novel liquid metal patterning technique: voltage induced non-contact electrochemical lithography at room temperature

Non-contact, maskless, voltage induced electrochemical lithography for liquid metals was demonstrated at room temperature. Various patterns in liquid metal can be simply and rapidly fabricated using electrochemical hole/dot matrix printing, continuous “writing” and a movable type printing method.

Point defect induced giant enhancement of flux pinning in Co-doped FeSe0.5Te0.5 superconducting single crystals

Point defect pinning centers are the key factors responsible for the flux pinning and critical current density in type II superconductors. The introduction of the point defects and increasing their density without any changes to the superconducting transition temperature Tc, irreversibility field Hirr, and upper critical field Hc2, would be ideal to gain insight into the intrinsic point-defect-induced pinning mechanism. In this work, we present our investigations on the critical current density Jc, Hc2, Hirr, the activation energy U0, and the flux pinning mechanism in Fe1-xCoxSe0.5Te0.5 (x = 0, 0.03 and 0.05) single crystals. Remarkably, we observe that the Jc and U0 are significantly enhanced by up to 12 times and 4 times for the 3at.% Co-doped sample, whereas, there is little change in Tc, Hirr, and Hc2. Furthermore, charge-carrier mean free path fluctuation, δl pinning, is responsible for the pinning mechanism in Fe1-xCoxSe0.5Te0.5.