Carbon monoxide powered fuel cell towards H2-onboard purification

Proton exchange membrane fuel cells (PEMFCs) suffer extreme CO poisoning even at PPM level (<10 ppm), owning to the preferential CO adsorption and the consequential blockage of the catalyst surface. Herein, however, we report that CO itself can become an easily convertible fuel in PEMFC using atomically dispersed Rh catalysts (Rh-N-C). With CO to CO2 conversion initiates at 0 V, pure CO powered fuel cell attains unprecedented power density at 236 mW cm-2, with maximum CO turnover frequency (64.65 s-1, 363 K) far exceeding any chemical or electrochemical catalysts reported. Moreover, this feature enables efficient CO selective removal from H2 gas stream through the PEMFC technique, with CO concentration reduced by one order of magnitude through running only one single cell, while simultaneously harvesting electricity. We attribute such catalytic behavior to the weak CO adsorption and the co-activation of H2O due to the interplay between two adjacent Rh sites.