Efficient Bipolar Membrane with Functionalized Graphene Oxide Interfacial Layer for Water Splitting and Converting Salt into Acid/Base by Electrodialysis

The layer-by-layer casting technique was adopted to fabricate bipolar membranes (BPMs) comprising a cation-exchange layer (CEL), an interfacial layer (IL, phosphorylated graphene oxide (PGO) and/or quatemized graphene oxide (QGO)), and an anion-exchange layer (AEL). Under applied dc potential gradient, water molecules dissociate at the IL and generate H+ and OH-. The effect of the IL nature (PGO, QGO, and mixed PGO/QGO) on the water splitting performance of the BPM was thoroughly studied. Well optimized BPM-PGO/QGO exhibited high current efficiency (CE) and low energy consumption and was assessed to be superior in comparison with different commercial BPMs. The reported BPM showed improved water splitting performance, significant reduction in resistance, and high permselectivity (low co-ion leakage) for over 10 experimental cycles. Relatively stable performance of BPM-PGO/QGO made it industrially viable for water splitting.