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

Abstract

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.