Alloyed Palladium–Lead Nanosheet Assemblies for Electrocatalytic Ethanol Oxidation

Abstract

Synthesizing alloyed bimetallic electrocatalysts with a three-dimensional (3D) structure assembly have arouse great interests in electrocatalysis. We synthesized a class of alloyed Pd3Pb/Pd nanosheet assemblies (NSAs) composed of a two-dimensional (2D) sheet structure with adjustable compositions via an oil bath approach at a low temperature. Both the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images reveal the successful formation of the nanosheet structure, where the morphology of Pd3Pb/Pd NSAs can be regulated by adjusting the atomic mole ratio of Pb and Pb metal precursors. The power X-ray diffraction (XRD) pattern shows that Pd3Pb/Pd NSA catalysts are homogeneously alloyed. Electrochemical analysis and the density functional theory (DFT) method demonstrate that the electrocatalytic activity of the alloyed Pd3Pb/Pd NSAs can be improved by the doping of the Pb element. As a result of the addition of element Pb and change of the electron structure, the electrocatalytic activity toward ethanol oxidation of alloyed Pd3Pb/Pd-15 NSA can reach up to 2886 mA mg–1, which is approximately 2.8 times that of the pure Pd NSA counterpart (1020 mA mg–1). The Pd3Pb/Pd NSAs are favorable in a high catalytic temperature, high KOH concentration, and high ethanol concentration.

Improvement of electrocatalytic alcohol oxidation by tuning the phase structure of atomically ordered intermetallic Pd-Sn nanowire networks

“…In Fig. 5f, the MAs of various Pd-Sn OICs are much higher than that of Pd-Fm m 3 , and PdSn-Pnmb OIC exhibits the highest value, further indicating the outstanding stability can be attributed to the stable crystal structure of OICs [53].…”

Controllable Lattice Expansion of Monodisperse Face-Centered Cubic Pd–Ag Nanoparticles for C1 and C2 Alcohol Oxidation: The Role of Core–Sheath Lattice Mismatch

“…(i) Powder Xray diffraction (PXRD) is an obvious method for assessing lattice strain. 20,21 Clearly, the positive or negative shifting of the diffraction peaks indicates the lattice contraction or expansion, respectively. 5,22 (ii) Aberration-corrected highresolution transmission electron microscopy (HRTEM) can compare the interlaying spacing of the metals.…”

“…The Pd 5 Ag 1 NPs have a Pd mass-normalized current density of 2402 mA mg Pd −1 toward EOR, 4.4 times higher than that of the commercial Pd/C counterpart, as shown in Figure 4a,b Actually, the reaction is predominated by the latter due to the extremely high energy of breaking the C−C bonds, where the EOR reacts on the α-C atoms but not β-C atoms. 21 The ethanol molecules would adsorb on the interface of PdAg NPs and would react with OH* to form acetic acid (possible mechanism: 47 The long-term durability of PdAg NP electrocatalysts was assessed by the chronoamperometry (CA) methods. In Figure 4c, each of the PdAg NPs catalysts shows a different degree of decrease, and Pd 5 Ag 1 NPs alone exhibit the highest MA values among those NPs with varied silver fractions.…”

“…There are several ways to characterize strain. (i) Powder X-ray diffraction (PXRD) is an obvious method for assessing lattice strain. , Clearly, the positive or negative shifting of the diffraction peaks indicates the lattice contraction or expansion, respectively. , (ii) Aberration-corrected high-resolution transmission electron microscopy (HRTEM) can compare the interlaying spacing of the metals . Cui et al reported the direct and continuous strain control of catalysts, where the lattice compression or expansion phenomena can be assessed by the decreased or increased spacing of Pt .…”

Unveiling the Synergistic Effects of Monodisperse Sea Urchin-like PdPb Alloy Nanodendrites as Stable Electrocatalysts for Ethylene Glycol and Glycerol Oxidation Reactions

“…15 This would change the electron structures of the Pd-based catalysts, followed by the adjustment of the absorptions of the OH* and C 2 intermediates, and it, therefore, leads to an enhancement of the electrocatalytic activity. 15,27 Also, many studies have reported the synthesis of Pd nanocatalysts with various morphologies with great electrocatalytic activities, such as nanoparticles, nanorods, nanosheets, nanotubes, nanocubes, and nanowires. 30 However, recent research has presented that toxic intermediates in the EOR process are well tolerated by reducing the binding strength of Pd−CO or by promoting the reaction more thoroughly.…”