No abstract

Graphene and its functionalized derivatives are unique and versatile building blocks for self-assembly to fabricate graphene-based functional materials with hierarchical microstructures. Here we report a strategy for three-dimensional self-assembly of graphene oxide sheets and DNA to form multifunctional hydrogels. The hydrogels possess high mechanical strength, environmental stability, and dye-loading capacity, and a exhibit self-healing property. This study provides a new insight for the assembly of functionalized graphene with other building blocks, especially biomolecules, which will help rational design and preparation of hierarchical graphene-based materials.

The recent boom in multifunction portable electronic equipments requires the development of compact and miniaturized electronic circuits with high efficiencies, low costs and long lasting time. For the operation of most line-powered electronics, alternating current (ac) line-filters are used to attenuate the leftover ac ripples on direct current (dc) voltage busses. Today, aluminum electrolytic capacitors (AECs) are widely applied for this purpose. However, they are usually the largest components in electronic circuits. Replacing AECs by more compact capacitors will have an immense impact on future electronic devices. Here, we report a double-layer capacitor based on three-dimensional (3D) interpenetrating graphene electrodes fabricated by electrochemical reduction of graphene oxide (ErGO-DLC). At 120-hertz, the ErGO-DLC exhibited a phase angle of −84 degrees, a specific capacitance of 283 microfaradays per centimeter square and a resistor-capacitor (RC) time constant of 1.35 milliseconds, making it capable of replacing AECs for the application of 120-hertz filtering.

Inorganic perovskite quantum dots as optoelectronic materials have attracted enormous attention in light-harvesting and emitting devices. However, photocatalytic conversion based on inorganic perovskite halides has not been reported. Here, we have synthesized colloidal quantum dots (QDs, 3-12 nm) of cesium lead halide perovskites (CsPbBr ) as a new type of photocatalytic material. The band gap energies and photoluminescence (PL) spectra are tunable over the visible spectral region according to quantum size effects on an atomic scale. The increased carrier lifetime revealed by time-resolved PL spectra, indicates the efficient electron-hole separation and transfer. As expected, the CsPbBr QDs with high selectivity of greater than 99 % achieve an efficient yield of 20.9 μmol g towards solar CO reduction. This work has opened a new avenue for inorganic colloidal perovskite materials as efficient photocatalysts to convert CO into valuable fuels.

ZnO1-x/graphene hybrid photocatalyst was prepared via a facile in-situ reduction of graphene oxide and ZnO1-x surface defect oxide. The hybrid photocatlayst showed enhanced photocatalytic activity for the photodegradation of methylene blue. The photocorrosion of ZnO1-x was successfully inhibited by graphene hybridation. ZnO1-x/graphene hybrid photocatalyst with 1.2 wt % graphene showed the optimized photocatalytic activity. The photocatalytic activity of ZnO1-x/graphene-1.2 wt % under visible and UV light was about 4.6 and 1.2 times that of ZnO1-x sample, respectively. The photocurrent intensity of ZnO1-x under visible and UV light irradiation can be enhanced by 2 and 3.5 times by graphene hybridization. The enhancement of photocatalytic activity and photocurrent intensity in ZnO1-x/graphene was attributed to the synergistic effect between graphene and ZnO1-x for high separation efficiency of photoinduced electron-hole pairs mainly resulting from the promotion of HOMO orbit of graphene and the Oi″ defect level of ZnO1-x in ZnO1-x/graphene.