Research

Exfoliated MoS2 nanosheets loaded on bipolar exchange membranes interfaces as advanced catalysts for water dissociation

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Abstract

Over the last few decades, ion exchange membranes have evolved from a laboratory tool to industrial products with significant technical and commercial impacts. Electrodialysis with bipolar membranes (EDBM) is a technology that can produce acids and bases from the corresponding salt solutions. Bipolar membranes are key factors for splitting water at the interface of a cation and anion exchange layer in an electric field. The ideal bipolar membrane should have a low energy consumption, a high current efficiency and long-term stability. In order to investigate the catalytic effect of a monolayer of MoS2, the bipolar membranes were prepared by introducing monolayer MoS2 to the interface of bipolar membranes. The resulting bipolar membrane was found to have lower potential drop, which clearly demonstrates the applicability of the MoS2 layer to act as catalyst. Enhanced acid production confirmed this prediction. Furthermore, a bipolar membrane prepared at 90°C had a low swelling ratio of about 7.5% while maintaining a high water uptake of 71.6%. From the calculation of current efficiency and energy consumption, the bipolar membrane with a monolayer of MoS2 has a higher current efficiency (45%) and a lower energy consumption (3.6 kW/h·kg) compared to a current efficiency of 24% and an energy consumption of 6.3 kW/h·kg for a bipolar membrane without MoS2. This study proves the catalytic function of MoS2, which lays a foundation for further research on catalytic bipolar exchange membranes.