Core-shell composites with strong phase-phase contact could provide an incentive for catalytic activity. A simple, yet efficient, HO-mediated method has been developed to synthesize a mesoscopic core-shell W@WC architecture with a dodecahedral microstructure, via a one-pot reaction. The HO plays an important role in the resistance of carbon diffusion, resulting in the formation of the W core and W-terminated WC shell. Density functional theory (DFT) calculations reveal that adding W as core reduced the oxygen adsorption energy and provided the W-terminated WC surface. The W@WC exhibits significant electrocatalytic activities toward hydrogen evolution and nitrobenzene electroreduction reactions, which are comparable to those found for commercial Pt/C, and substantially higher than those found for meso- and nano-WC materials. The experimental results were explained by DFT calculations based on the energy profiles in the hydrogen evolution reactions over WC, W@WC, and Pt model surfaces. The W@WC also shows a high thermal stability and thus may serve as a promising more economical alternative to Pt catalysts in these important energy conversion and environmental protection applications. The current approach can also be extended or adapted to various metals and carbides, allowing for the design and fabrication of a wide range of catalytic and other multifunctional composites.

The spray-dried spheres within a W/Pt multi-separation can be used to prepare discrete core-shell WC@C/Pt catalysts through a typical carburization production mechanism at 800 • C. In contrast with previous studies of the WC/Pt synthesis, the reaction observed here proceeds through an indirect annealing mechanism at 600 • C wherein species diffuse, thereby resulting in core-shell structure, and Pt nanoparticles were successfully dispersed in size/shape and randomly scattered across the in situ produced C spheres. Through direct carburization or at higher initial hydrochloroplatinic acid concentrations, however, complete reaction with core-shell spheres was not observed. Indirect carburization reduces the strain felt by the bonds featuring the larger WC particles and allows the motion of carbon around WC and Pt nanoparticles to be reserved, influencing the electrocatalytic performance and stability toward methanol oxidation.

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.