Hong Meng

Green synthesis and photo-catalytic performances for ZnO-reduced graphene oxide nanocomposites.

The zinc oxide (ZnO)-reduced graphene oxide (RGO) nanocomposites were greenly synthesized by one-step hydrothermal reaction with ZnCl2 and graphite oxide (GO) as precursors without extra reductant. The photo-catalytic performances consisting of the photo-degradation of Rhodamine B (RhB) and the photo-reduction of CO2 under the illumination of simulated solar light at ambient temperature were investigated. It was validated that the ZnO spherical particles assembled by ZnO nanorods with an average diameter of 150nm are uniformly deposited on the RGO sheets. Meanwhile, due to the introduction of RGO, the light adsorption scope of ZnO is enlarged, the size of ZnO is decreased, the degree of crystallinity is improved and the self-aggregation of the ZnO particles is effectively prevented. Comparing with the pure ZnO particles, the efficiency of the nanocomposites for the photo-degradation of RhB is increased by 39% and the yield of methanol from the reduction of CO2 is improved by 75%. The mechanisms that may explain the enhanced properties of as-synthesized ZnO-RGO for both the photo-degradation of RhB and the reduction of CO2 were also proposed.

Rapid spray-crosslinked assembly of a stable high-performance polyelectrolyte bipolar membrane

Bipolar membrane processes have evolved as one of the most promising technologies in the field of acid and base production as well as many interesting separation applications. Herein, we report a rapid spray-crosslinked assembly for fabricating a high-performance polyelectrolyte bipolar membrane. Polyvinyl alcohol (PVA), glutaricdialdehyde (GA) and polyethyleneimine (PEI) are alternatively and successively sprayed onto a supporting cation-exchange membrane. GA crosslinked PVA and PEI are responsible for the interlayer and anion-exchange layer, respectively. Under optimal conditions, at a current density of 100 mA cm−2, the cell voltage of the BPM was as low as 1.79 V. Moreover, it has been demonstrated that the spray crosslinked membrane has good stability in acid and alkali harsh conditions. In contrast to the traditional casting method, spray assembly combined with chemical cross-linking can tune the membrane thickness at the nanoscale and microscale levels, as well as increase its charge density and ion-exchange capacity. This facile approach might open a new way to efficiently and flexibly produce various bipolar membranes with different polyelectrolytes.