A Phosphorus‐Doped Ag@Pd Catalyst for Enhanced CC Bond Cleavage during Ethanol Electrooxidation

Abstract

a direct alkaline ethanol fuel cell owns more advantages. [4-6] For example, the production of ethanol from biomass is nonpoisonous and convenient. Ethanol is safe to be stored. More importantly, ethanol can be directly oxidized into CO 2 in an alkaline medium. [7,8] This complete ethanol oxidation reaction (EOR) involves the transfer of 12 electrons (Equation (1)), leading to a much higher energy density (e.g., 6.34 kWh L −1 for ethanol). Unfortunately, this EOR is kinetically sluggish in that the stable CC bond in ethanol molecules has to be broken. Given this fact, ethanol is much easier to be oxidized into acetate rather than CO 2. This oxidation pathway delivers only 4 electrons (Equation (2)). Based on the numbers of carbon atoms in the products and electrons transferred per ethanol molecule, these EOR pathways are termed as C1-12e and C2-4e, respectively. [7-10] In terms of energy density of the EOR, the C2-4e pathway has a three times lower efficiency than that of the C1-12e one. To improve the energy efficiency of direct ethanol fuel cells, advanced electrocatalysts that favor the C1-12e EOR pathway are thus are highly pursued.

Modulating Electronic Structure of an Au‐Nanorod‐Core–PdPt‐Alloy‐Shell Catalyst for Efficient Alcohol Electro‐Oxidation

“…Consequently, the Au@PdPt core–shell catalyst has a better ability to adsorb CH 3 OH and OH. [ 33 ] In addition, the Au@PdPt core–shell catalyst has the lowest charge‐transfer resistance ( R ct = 2.3 KΩ), as calculated from the Nyquist plots of these catalysts (Figure 3e). It is thus beneficial for the charge transfer of the MOR.…”

“…Based on the areas of these CO‐stripping peaks, the calculated electrochemical active surface areas (ECSAs) of the catalysts of Au@PdPt, Pd nanoparticles, Pt nanoparticles, and the PdPt alloy (Table S1, Supporting Information) are 70.3, 22.4, 35.3, and 35.8 m 2 g –1 , respectively. [ 33 ] The Au@PdPt core–shell catalyst exhibits the biggest ECSA, namely more active sites. Hence, this Au@PdPt core–shell catalyst is expected to be a promising catalyst for the AORs.…”

“…[34][35][36][37][38][39][40][41] For example, an expanded strain increases the d-band center of the active shell, resulting in strengthened adsorption of ethanol and OH species, and eventually much facilitated ethanol electrooxidation. [33] Moreover, the exposed crystal plane on the shell is possible to be modified during an epitaxial growth process. For example, the exposed facets of an Ir shell have been derived from a Pd core in a Pd@Ir core-shell catalyst.…”

“…[ 25–30 ] Its structure and its catalytic activity of the shell are revealed to be highly dependent on the used core. [ 31–34 ] This is because the strain effect (expansion or compression) can be effectively controlled, up to the difference of intrinsic lattice parameters between the core and the shell. [ 34–41 ] For example, an expanded strain increases the d‐band center of the active shell, resulting in strengthened adsorption of ethanol and OH species, and eventually much facilitated ethanol electro‐oxidation.…”

“…[25][26][27][28][29][30] Its structure and its catalytic activity of the shell are revealed to be highly dependent on the used core. [31][32][33][34] This is because the strain effect (expansion or compression) can be Direct alcohol fuel cells (DAFCs) utilize alcohol electro-oxidation reactions (AORs) to provide electricity, where catalysts with optimal electronic structures are required to accelerate sluggish AORs. Herein, an electrocatalyst with an Au-nanorod core and a PdPt-alloy shell is designed.…”