Xuan Jian

A photocatalytic graphene quantum dots–Cu2O/bipolar membrane as a separator for water splitting

Graphene quantum dots–Cu2O (GQDs–Cu2O) is introduced to a bipolar membrane (BPM) interlayer and shown to be a novel, efficient water dissociation catalyst. This paper reports the use of the GQDs–Cu2O/BPM composite as a separator to prevent the crossover of hydrogen and oxygen. Under reverse bias and sunlight irradiation conditions, GQDs–Cu2O/BPM exhibits lower membrane resistance than BPM. GQDs–Cu2O/BPM also minimizes pH gradient formation, resulting in a decreased potential loss with respect to that of BPM. The efficiency of GQDs–Cu2O/BPM as a diaphragm in H2 generation and energy conservation was assessed. GQDs–Cu2O/BPM was found to be 88.6% and 14.5% more efficient than BPM in H2 generation at the current density of 90 mA cm−2 and under sunlight irradiation, respectively. The composite also saved about 22.6% energy with respect to that of BPM at 90 mA cm−2.

A BiOCl/bipolar membrane as a separator for regenerating NaOH in water-splitting cells

Photoconductive BiOCl has been introduced into a bipolar membrane (BPM) interlayer to prepare a BiOCl/BPM. This paper reports the use of the BiOCl/BPM composite to regenerate NaOH. Under reverse bias and sunlight irradiation conditions, the BiOCl/BPM resistance and cell voltage can be significantly decreased due to the photoconductivity of the BiOCl photocatalyst, which lead to the energy consumption decline in regenerating NaOH. Moreover, the electric field in the interlayer of the BiOCl/BPM contributes in separating the photo-generated electron–hole pairs of the BiOCl photocatalyst, thereby increasing the current efficiency of regenerating NaOH.