Facilitating the exposure of the active crystal facets on the surfaces of composite catalysts is a representative route to promote catalytic activity. Based on a tailored galvanic replacement reaction, herein, a self-assembly route is reported to prepare Pt−WC/CNT with Pt (200) preferential orientation and well-dispersed structure, which are capable of substantially boosting electrocatalysis in hydrogen evolution reaction (HER). Formation mechanism reveals that the (200)-dominated Ptbased catalysts form in galvanic replacement reaction through selective anchored on WC, and the multistep galvanic replacement process plays a critical role to realize the Pt (200)-dominated growth in higher Pt loading catalyst. These unique structural features endow the Pt−WC/CNT with a high turnover frequency of 94.18 H 2 •s −1 at 100 mV overpotential, 7-fold higher than that of commercial Pt/C (13.55 H 2 •s −1 ), ranking it among the most active catalysts. In addition, this method, which combines with gas−solid reaction and galvanic replacement reaction, paves the way to scalable synthesis as Pt facets-controllable composite catalysts to challenge commercial Pt/C.
The facet‐controlled Pt‐WC nanoparticles on in situ synthesized carbon nanotubes (Pt‐WC/CNT) are prepared by the one‐step carburization in conjunction with simple displacement reaction. WC particles exhibit preferential (100) orientation due to the in situ growth of carbon nanotubes (CNTs), and the most predominant facet exhibited by the Pt immobilized on WC (100) is the (200) facet. Among the prepared catalysts, Pt‐WC/CNT‐2 shows the highest mass activity (2540.0 mA/mg Pt) for methanol oxidation reaction (MOR) with smaller onset overpotential (0.18 V) and lower activation free energy (32.87 kJ/mol) in acid media. Such enhanced catalytic activity originates from its larger ECSA (238.1 m2/g) and the synergistic effect of facet‐controlled Pt‐WC nanoparticles. And Pt‐WC/CNT catalyst has superior stability for MOR due to its structurally stable CNTs support, which provides a large area to contact with electrolyte, and facilitates the electron transfer.
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