This study developed a facile approach for preparing Ti3+ self-doped TiO2-graphene photocatalyst by a one-step vacuum activation technology involved a relative lower temperature, which could be activated by the visible light owing to the synergistic effect among Ti3+ doping, some new intersurface bonds generation and graphene oxide reduction. Compared with the traditional methods, the vacuum activation involves a low temperature and low-costing, which can achieve the reduction of GO, the self doping of Ti3+ in TiO2 and the loading of TiO2 nanoparticles on GR surface at the same time. These resulting TiO2-graphene composites show the high photodegradation rate of MO, high hydrogen evolution activity and excellent IPCE in the visible light irradiation. The facile vacuum activation method can provide an effective and practical approach to improve the performance of TiO2-graphene and other metal oxides-graphene towards their practical photocatalytic applications.

Highly-dispersed boron-doped graphene nanoribbons (B-GNRs), prepared by a simple vacuum activation method, exhibit p-type semiconductor properties and provide many more zigzag- and armchair-edges to facilitate control of the bandgap. B-GNRs are used for the photodegradation of Rhodamine B in order to demonstrate their excellent conductivity and photocatalytic activity.

Droplet motion control on slippery liquid-infused porous surfaces (SLIPS) that mimics the peristome surface of Nepenthes alata has promising applications in the fields of energy, lab-on-a-chip device, etc., yet is limited due to the difficulty in regulating its wettability. In this work, topologies with specific functions from natural creatures, for example, grooved structures of rice leaf and wedge-shaped structures of shore bird beak with droplet transporting capability were integrated with the SLIPS. Three-dimensional topological SLIPS was fabricated on metal substrates using laser milling followed by alkaline oxidation. Fabricated rice leaflike grooved nanotextured SLIPS can properly shape the droplet footprint to achieve a sliding resistance anisotropy of 109.8 μN, which is 27 times larger than that of a natural rice leaf and can therefore be used to efficiently and precisely transport droplets; wedge-shaped nanotextured SLIPS can confine the droplet footprint and squeeze droplet to produce a Laplace pressure gradient for continuous self-driven droplet transport. The created surfaces can manipulate droplets of acid, alkali, and salt solutions. The proposed concept is believed to have potential applications for condensing heat transfer and droplet-based lab-on-a-chip devices.

Superhydrophobic-superhydrophilic patterned surfaces have attracted more and more attention due to their great potential applications in the fog harvest process. In this work, we developed a simple and universal electrochemical-etching method to fabricate the superhydrophobic-superhydrophilic patterned surface on metal superhydrophobic substrates. The anti-electrochemical corrosion property of superhydrophobic substrates and the dependence of electrochemical etching potential on the wettability of the fabricated dimples were investigated on Al samples. Results showed that high etching potential was beneficial for efficiently producing a uniform superhydrophilic dimple. Fabrication of long-term superhydrophilic dimples on the Al superhydrophobic substrate was achieved by combining the masked electrochemical etching and boiling-water immersion methods. A long-term wedge-shaped superhydrophilic dimple array was fabricated on a superhydrophobic surface. The fog harvest test showed that the surface with a wedge-shaped pattern array had high water collection efficiency. Condensing water on the pattern was easy to converge and depart due to the internal Laplace pressure gradient of the liquid and the contact angle hysteresis contrast on the surface. The Furmidge equation was applied to explain the droplet departing mechanism and to control the departing volume. The fabrication technique and research of the fog harvest process may guide the design of new water collection devices.

Four-dimensional (4D) printing of shape memory polymer (SMP) imparts time responsive properties to 3D structures. Here, we explore 4D printing of a SMP in the submicron length scale, extending its applications to nanophononics. We report a new SMP photoresist based on Vero Clear achieving print features at a resolution of ~300 nm half pitch using two-photon polymerization lithography (TPL). Prints consisting of grids with size-tunable multi-colours enabled the study of shape memory effects to achieve large visual shifts through nanoscale structure deformation. As the nanostructures are flattened, the colours and printed information become invisible. Remarkably, the shape memory effect recovers the original surface morphology of the nanostructures along with its structural colour within seconds of heating above its glass transition temperature. The high-resolution printing and excellent reversibility in both microtopography and optical properties promises a platform for temperature-sensitive labels, information hiding for anti-counterfeiting, and tunable photonic devices.