Er Chieh Cho

Few-layer graphene based sponge as a highly efficient, recyclable and selective sorbent for organic solvents and oils

In this work, we illustrate a facile and economical strategy for the bulk production of aqueous few layer graphene (FLG) dispersions via a simple grinding method. The as-prepared FLG suspensions can be cast on various substrates through facile dip coating. The environmentally friendly one-step procedure can produce graphene-based surfaces easily without additional reduction reaction. Here, we also prepare the FLG-based sponges with both superhydrophobic and superoleophilic properties. The FLG-sponges have been demonstrated as efficient absorbents for a broad range of oils and organic chemicals with high selectivity and excellent recyclability. The FLG-sponges deliver an absorption capacity as high as 153 g g−1 for the chloroform. The results indicate that the FLG sponges may potentially be useful as next-generation oil adsorbent materials.

Three-Dimensional Conductive Nanocomposites Based on Multiwalled Carbon Nanotube Networks and PEDOT:PSS as a Flexible Transparent Electrode for Optoelectronics.

UNLABELLED We have synthesized conductive nanocomposites composed of multiwalled carbon nanotubes (MWCNTs) and Au nanoparticles (NPs). The Au NPs with an average size of approximately 4.3 nm are uniformly anchored on the MWCNT. After being exposed to microwave (MW) plasma irradiation, the anchored Au NPs melt and fuse, leading to larger aggregates (34 nm) that can connect the MWCNT forming a three-dimensional conducting network. The formation of a continuous MWCNT network can produce more a conductive pathway, leading to lower sheet resistance. When the Au-MWCNT is dispersed in the highly conductive polymer, poly(ethylene dioxythiophene):polystyrenesulfonate ( PEDOT PSS), we can obtain solution-processable composite formulations for the preparation of a flexible transparent electrode. The resulting Au-MWCNT/PEDOT:PSS hybrid films possess a sheet resistance of 51 Ω/sq with a transmittance of 86.2% at 550 nm. We also fabricate flexible organic solar cells and electrochromic devices to demonstrate the potential use of the as-prepared composite electrodes. Compared with the indium tin oxide-based devices, both the solar cells and electrochromic devices with the composites incorporated as a transparent electrode deliver comparable performance.

Carboxyfullerene decorated titanium dioxide nanomaterials for reactive oxygen species scavenging activities

Titanium dioxide nanomaterials offer superior protection for human skin against ultraviolet light. However, some reports have indicated that they might be associated with adverse effects such as cytotoxicity or reactive oxygen species (ROS) under UV-irradiation due to their nanoscale size. The surfaces of fullerenes are covered with π electrons, constituting aromatic structures, which can effectively scavenge large amounts of radicals. Unfortunately, their poor solubility in water, severe aggregation, and toxicity in biological applications when dispersed in solvent have imposed limitations on the use of fullerenes. Herein, we used carboxyfullerene as a radical scavenger to improve poor solubility. The modified materials were prepared through the esterification of C70-COOH with TNR (TNR/C70-COOH) and P25 (P25/C70-COOH). The structures and the properties were analyzed by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and high-resolution transmission electron microscopy (HRTEM). In order to investigate the scavenging radical abilities of TiO2 composites, pyridoxine (Vit. B6), nitroblue tetrazolium (NBT) and terephthalic acid (TA) were chosen to react with singlet oxygen, superoxide ions and hydroxyl radicals, respectively. The results show that both types of TiO2 composites could reduce the ROS in the environment and exhibit great potential in anti-oxidative and anti-inflammation applications.