Fabricating Core-Shell WC@C/Pt Structures and its Enhanced Performance for Methanol Electrooxidation

Abstract

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.

Synergistic and Durable Pt-WC Catalyst for Methanol Electro-Oxidation in Ionic Liquid Aqueous Solution

“…Hence, all the current densities were normalized by the mass of loaded Pt. The forward peak current density of MOR on 10% Pt-WC/C (Figure S4a) was up to 594.3 mA mg –1 , about 2.0, 2.7, and 3.3 times higher than those on JM 20% Pt/C (298.2 mA mg –1 ), 5% Pt-WC/C (221.0 mA mg –1 ), and 15% Pt-WC/C (182.0 mA mg –1 ) catalysts, respectively, which was also more competitive than those of recent state-of-the-art WC-based nanostructures such as Pt/WC/GC catalyst, Pt@WC/OMC, and WC@C/Pt . The apparent activation energies ( E ap ) can be obtained from the slopes of Arrhenius plots (Figure S5) at both applied potentials.…”

“…The forward peak current density of MOR on 10% Pt-WC/C (Figure S4a) was up to 594.3 mA mg −1 , about 2.0, 2.7, and 3.3 times higher than those on JM 20% Pt/C (298.2 mA mg −1 ), 5% Pt-WC/C (221.0 mA mg −1 ), and 15% Pt-WC/C (182.0 mA mg −1 ) catalysts, respectively, which was also more competitive than those of recent state-of-the-art WC-based nanostructures such as Pt/WC/GC catalyst, 10 Pt@WC/ OMC, 11 and WC@C/Pt. 12 The apparent activation energies (E ap ) can be obtained from the slopes of Arrhenius plots (Figure S5) at both applied potentials. The E ap value is found as 28.5 kJ mol −1 at 0.5 V and 34.0 kJ mol −1 at 0.6 V for 10% Pt-WC/C electro-catalysts, which is lower than those of 20% JM Pt/C (65.4 and 48.3 kJ mol −1 ).…”