Facile Synthesis of Highly Active Three-Dimensional Urchin-like Pd@PtNi Nanostructures for Improved Methanol and Ethanol Electrochemical Oxidation

Abstract

Exploitation of highly active catalysts for alcohol electrooxidation is urgent for direct alcohol fuel cells (DAFCs). In this research, a facile and mild synthetic approach is utilized to control and tailor the morphology of the three-dimensional (3D) urchin-like Pd@PtNi nanostructures (NSs), and the formation mechanism of the as-prepared nanostructures is expounded in detail. The Pd@PtNi NSs exhibit outstanding electrochemical properties and remarkable durability toward both methanol and ethanol oxidation reaction (MOR and EOR) in alkaline solution. The electrochemically active surface area (ECSA) of the Pd@PtNi NSs is 59.5 m 2 g −1 , and their mass activities for MOR and EOR are 1614.3 and 1502.3 mA mg −1 , respectively, which are much higher than those of their ternary or binary alloy counterparts as well as commercial Pt black catalysts. Moreover, it still retains high current densities after catalyzing 10 000 s, while the current densities of other nanocatalysts reduce to nearly zero. The outstanding electrochemical activities and durability are owing to the specific 3D urchin-like nanostructures providing enormous active sites for catalytic reaction and the synergy effects between Pt, Pd, and Ni atoms. The 3D urchin-like Pd@PtNi NSs will enrich the electrocatalysts for DAFCs.

Facile Synthesis Of Composition‐Controllable PtPdAuTe Nanowires As Superior Electrocatalysts For Direct Methanol Fuel Cells

“…[21] In addition, the bifunctional mechanism, electronic and synergistic effects between different metals in Pt-based nanomaterials could enhance electrocatalytic performance and stability for methanoloxidation. [22,23] The methodsf or preparing nanomaterials mainlyi nclude chemicalr eduction method, [24] template approach, [25] solvothermal( hydrothermal)m ethod, [26] electrochemical deposition, [1] and electrospinning, [23] etc. Amongt hem, the template methodi saversatile strategy to preparen anocatalysts with variouss tructural morphologies.…”

Facile Synthesis of PdCu Echinus‐Like Nanocrystals as Robust Electrocatalysts for Methanol Oxidation Reaction

“…This kind of novel echinus-like nanoarchitectures not merely can provide abundant active sites but also accelerate the process of mass and electron exchange, in favor of boosting the activity for MOR. [36,42] The polycrystalline characteristico fe chinus-likeP dCu NCs was verified by selective area electron diffraction (SAED) pattern which was shown in the inset of Figure 1c.T he lattice spacingo f PdCu NCs was estimated to be 0.22 nm, whichi sa mong Pd (111)p lane (0.230 nm) and Cu (111)p lane (0.209 nm), demonstratingt he successful fabrication of PdCu alloy (Figure 1d). [43,44] In order to furtherp rove the formationo fP dCua lloy, HAADF-STEM and EDS were employed for analyzing the elemental distribution and composition.…”

“…Numerous straight and long branches with 70–80 nm in length can be found in the nanostructures (Figure c). This kind of novel echinus‐like nanoarchitectures not merely can provide abundant active sites but also accelerate the process of mass and electron exchange, in favor of boosting the activity for MOR . The polycrystalline characteristic of echinus‐like PdCu NCs was verified by selective area electron diffraction (SAED) pattern which was shown in the inset of Figure c. The lattice spacing of PdCu NCs was estimated to be 0.22 nm, which is among Pd (111) plane (0.230 nm) and Cu (111) plane (0.209 nm), demonstrating the successful fabrication of PdCu alloy (Figure d) …”

“…For investigating the durability of products, chronoamperometry tests were performed in 1.0 m KOH with 1.0 m CH 3 OH at an invariable potentialo fÀ0.2 Vf or 10 000 s. As depicted in Figure 5d,t he current densities of obtained electrocatalysts and Pd/C both declined sharply in the initiation stage, which were caused by the poisoning effect of the carbonaceous intermediates. [42,60] Notably,P dCu NCs manifest slowest current decay during the process of CA tests. After 10 000 s, the residual mass activity of PdCu NCs is much higher than that of other electrocatalysts, suggesting its outstanding electrocatalytic durability.F urthermore, the stabilityo fo btained electrocatalysts and Pd/C were investigated by continuous CV scanning for 500 cycles.A si llustrated in Figure 6a,P dCu NCs exhibit the highest current density throughout the entire tests.…”

“…For investigating the durability of products, chronoamperometry tests were performed in 1.0 m KOH with 1.0 m CH 3 OH at an invariable potential of −0.2 V for 10 000 s. As depicted in Figure d, the current densities of obtained electrocatalysts and Pd/C both declined sharply in the initiation stage, which were caused by the poisoning effect of the carbonaceous intermediates . Notably, PdCu NCs manifest slowest current decay during the process of CA tests.…”