Confining rhodium nanocrystals into polyaniline nanorod-embedded MXene nanoarchitectures enables efficient methanol electrooxidation.

Although metallic rhodium (Rh) is regarded as a promising platinum (Pt)-alternative electrode used in direct methanol fuel cell technology, its electrocatalytic ability still needs to be substantially improved before large-scale commercial applications. Herein, we report a bottom-up design strategy to confine ultrafine Rh nanoparticles into polyaniline (PANI) nanorod-embedded Ti3C2Tx MXene nanoarchitectures through a convenient co-assembly process. The incorporation of PANI nanorods effectively separates the neighbouring MXene nanolayers and provides plentiful N species for the immobilization of Rh nanoparticles, while the presence of MXene is able to optimize the intrinsic Rh electronic structure and guarantee a high charge-transfer efficiency. As a result, the newly-developed ternary electrocatalyst expresses superior methanol oxidation properties with a large electrochemical active surface area of 92.0 m2 g-1, high mass/specific activities of up to 1430.0 mA mg-1/1.55 mA cm-2, strong carbon monoxide resistance, and dependable long-term stability, far surpassing those of reference Rh/MXene, Rh/PANI, Rh/reduced graphene oxide, Rh/carbon nanotube, Rh/carbon black, and the widely used Pt/carbon black and Pd/carbon black catalysts.