In Situ Replacement Synthesis of Co@NCNT Encapsulated CoPt₃ @Co₂ P Heterojunction Boosting Methanol Oxidation and...

Simultaneous boosting electrochemical methanol oxidation reaction (MOR) for direct methanol fuel cells and production of hydrogen is meaningful but challenging. Herein, a sea urchin-shaped cobalt-embedded N-doped carbon nanotubes (Co@NCNT) encapsulated CoPt₃ @Co₂ P heterojunction (CoPt₃ @Co₂ P/Co@NCNT) is fabricated. Theoretical calculations confirm that electrons at the interfaces transfer from CoPt₃ to Co₂ P, where electron hole region on CoPt₃ is beneficial to improving the MOR activity, whereas accumulation region on Co₂ P favors to the optimization of H₂ O and H* absorption energies for hydrogen evolution reaction (HER). Benefitting from its interfacial electronic reconfiguration, the CoPt₃ @Co₂ P/Co@NCNT heterojunction exhibits excellent electrocatalytic performances for MOR and HER, in which the mass activity (2981 mA mg_Pt ^-1 ) for MOR is 14.2 times than that of Pt/C (20%), and the smallest overpotentials only requires 19 mV to deliver a current density of 10 mA cm^-2 for HER. Moreover, the electrolyzer employing CoPt₃ @Co₂ P/Co@NCNT for anodic MOR and cathodic H₂ production only requires a low voltage of 1.43 V at 10 mA cm^-2 with impressive long-life cycling stability, which is obviously better than that of commercial Pt/C//RuO₂ . This study offers a novel strategy for other organics oxidation reaction coupled with HER catalyzed production of hydrogen.