Bromate catalytic reduction in continuous mode using metal catalysts supported on monoliths coated with carbon nanofibers

•Catalytic reduction using Pd on CNF monoliths is effective in the removal of bromates.•The CNF coated structured reactor is robust and stable catalyst in continuous tests.•Pd catalyst on CNF/monolith showed 3-fold higher intrinsic activity than Pd/CNF/SMF.•Pd catalyst is more active than Ru catalyst.•Nitrogen doped CNF does not enhance the performance compared to the un-doped CNF.

Nitrogen-doped and un-doped carbon nanofibers layers, denoted as N-CNFs and CNFs respectively, coating the walls of cordierite monoliths have been used as support for Pd and Ru catalyst. They have been tested in bromate reduction in batch and continuous operation employing different reactor configurations. The CNF/monolith catalysts were benchmarked with Pd catalyst on CNF coated on another structured support, namely sintered metal fibers. CNF/monolith is a robust, active and stable catalyst for bromate reduction. The catalyst shows stable performance when operating in monolithic reactor and the CNFs showed excellent attachment to the monolith. The comparison of intrinsic activity of catalysts in batch experiments (free of diffusional limitations) revealed that Pd supported on CNF/monolith exhibited higher intrinsic activity than Pd on CNF/SMFs. Pd metal showed significantly higher specific activity than Ru. The doping of CNF with nitrogen, although contribute to decrease reoxidation propensity of metal does not supplies higher activity in bromate reduction.

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