Construction of Concave PdAg Nanoshells with Limited Thickness for Efficient Electroxidation of Ethanol

Quanlin Wu,Gongguo Zhang,Yanyun Ma,Na Zhao,Yiqun Zheng,Feng Liu,Maochang Liu

doi:10.3389/fmats.2021.761236

Quanlin Wu, Gongguo Zhang + Show 5 more

Open Access

https://doi.org/10.3389/fmats.2021.761236

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Abstract

Noble metal nanocrystals enclosed with curved surfaces are of great benefit for applications in electrocatalysis since the atomic steps and kinks on these facets have higher chemical activity. Herein, we report the fabrication of PdAg nanoshells with tunable thickness in the range of 5–13 nm and a unique concave cubic morphology, as well as the exploration of their applications for ethanol oxidation reaction (EOR) in alkaline media. The success of current work relies on the conformal deposition of PdAg on concave Au nanocubes, where the controlled reaction kinetics and proper chosen capping agent are both crucial for the growth mode. When loaded on carbon black and working as electrocatalysts, they exhibited superb electrochemical activity (e.g., 600.21 mA mg−1 in mass activity and 19.57 A m−2 in specific activity), together with improved EOR kinetics and long-term durability, as compared to Au@Pd nanoparticles and commercial Pd/C. The current work offers a feasible strategy to produce PdAg bimetallic nanocrystals with concave surface and validates their promising application as fuel cell catalysts, which could be extended to morphology engineering of other noble-metal nanocrystals for a broad range of applications.

Highlights

Ethanol oxidation reaction is one of the important classes of cathodic reaction for fuel cells that converts the chemical energy stored in liquid fuel to electricity(Mann et al, 2006; An and Zhao, 2011; Hong et al, 2019; Kim et al, 2019; Kim et al, 2020; Kabiraz et al, 2021)
The current work offers a feasible strategy to produce PdAg bimetallic nanocrystals with concave surface and validates their promising application as fuel cell catalysts, which could be extended to morphology engineering of other noble-metal nanocrystals for a broad range of applications
Typical synthesis started with the preparation of concave Au nanocubes in high purity according to the method described in our previous study (Zhang et al, 2020), followed by purification and the use as seeding material

Summary

Introduction

Ethanol oxidation reaction is one of the important classes of cathodic reaction for fuel cells that converts the chemical energy stored in liquid fuel to electricity(Mann et al, 2006; An and Zhao, 2011; Hong et al, 2019; Kim et al, 2019; Kim et al, 2020; Kabiraz et al, 2021). The electrochemical performance since it can tune the surface affinity towards key intermediates to achieve the maxima electrocatalytic activity along the volcano-type plot as a function of the heat of adsorption and enhanced anti-poisoning ability of the electrocatalyst (Zhang et al, 2016b) To this end, the electrochemical activity of many metal combinations, such as PdAu (Feng et al, 2013; Hong et al, 2014; Yang et al, 2017), PdPt (Dutta et al, 2016), PdAg (Lu and Chen, 2012; Peng et al, 2015; Bin et al, 2016; Fang et al, 2018; Lv et al, 2019; Yang et al, 2020a; You et al, 2020; Cui et al, 2021; Nguyen et al, 2021), PdCu (Wang et al, 2012; Hu et al, 2014; Liu et al, 2015; Jiang et al, 2016; Yang et al, 2019; Jana et al, 2021), PdPtCu (Wang et al, 2020), and phosphorousdoped Pd-based nanocrystals (Liu et al, 2019; Yang et al, 2020b; Lv et al, 2020; Yu et al, 2020), have been extensively measured, where the underlying mechanisms are investigated using theoretical deduction (i.e., d-band center theory) and in situ techniques (i.e., in situ FTIR)

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