Efficient removal of bromate from contaminated water using electrochemical ruthenium/MXene membrane via indirect...

Bromate contamination in global water bodies poses severe carcinogenic risks, necessitating efficient remediation technologies. While electrochemical reduction is promising, its practical application is often constrained by sluggish mass transfer and the low utilization efficiency of reactive atomic hydrogen (H*). Herein, we fabricated a Ru/MXene electrochemical membrane (RMEM) functioning as a flow-through cathode. Ru nanoclusters intercalated between MXene sheets suppress restacking, creating expanded pore channels with a 30.70% increase in pore diameter and 50.00% in porosity that maximize active site exposure. The flow-through architecture minimizes the diffusion distance between reactants and the catalytic surface, significantly intensifying convective mass transfer. Mechanistic investigations combined with DFT calculations revealed that H*-mediated indirect reduction is the dominant pathway. The Ru/MXene interface synergistically lowers the energy barrier for H* generation while suppressing H₂ evolution, thereby improving the utilization of H*. Under the optimal conditions (30 L m^-2 h^-1, 3.0 mA cm^-2), the RMEM achieved 99.37% bromate removal efficiency, outperforming conventional flow-by mode by 39.05%. During the continuous operation, removal remained stable at > 92% with competitive energy consumption of 3.24 ± 0.42 kWh/g BrO₃^-. The system maintained > 91% and > 86% efficiencies in the actual tap and surface water matrices. This study highlights the potential of electrochemical membranes for deep bromate remediation, offering a viable strategy for designing high-efficiency electroreduction technologies.