In Situ Replacement Synthesis of Co@NCNT Encapsulated CoPt @Co P Heterojunction Boosting Methanol Oxidation and Hydrogen Evolution.

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 CoPt @Co P heterojunction (CoPt @Co P/Co@NCNT) is fabricated. Theoretical calculations confirm that electrons at the interfaces transfer from CoPt to Co P, where electron hole region on CoPt is beneficial to improving the MOR activity, whereas accumulation region on Co P favors to the optimization of H O and H* absorption energies for hydrogen evolution reaction (HER). Benefitting from its interfacial electronic reconfiguration, the CoPt @Co P/Co@NCNT heterojunction exhibits excellent electrocatalytic performances for MOR and HER, in which the mass activity (2981 mA mg ) 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 for HER. Moreover, the electrolyzer employing CoPt @Co P/Co@NCNT for anodic MOR and cathodic H production only requires a low voltage of 1.43 V at 10 mA cm with impressive long-life cycling stability, which is obviously better than that of commercial Pt/C//RuO . This study offers a novel strategy for other organics oxidation reaction coupled with HER catalyzed production of hydrogen.