In Situ Exfoliation and Pt Deposition of Antimonene for Formic Acid Oxidation via a Predominant Dehydrogenation Pathway.

Yiqiong Zhang,Shuangyin Wang,Yafei Li,Zhijuan Liu,Yuqin Zou,Chung-Li Dong,Yucheng Huang,Man Qiao,Li Tao

doi:10.34133/2020/5487237

Abstract

Direct formic acid fuel cell (DFAFC) has been considered as a promising energy conversion device for stationary and mobile applications. Advanced platinum (Pt) electrocatalysts for formic acid oxidation reaction (FAOR) are critical for DFAFC. However, the oxidation of formic acid on Pt catalysts often occurs via a dual pathway mechanism, which hinders the catalytic activity owing to the CO poisoning. Herein, we directly exfoliate bulk antimony to 2D antimonene (Sb) and in situ load Pt nanoparticles onto antimonene sheets with the assistance of ethylenediamine. According to the Bader charge analysis, the charge transfer from antimonene to Pt occurs, confirming the electronic interaction between Pt and Sb. Interestingly, antimonene, as a cocatalyst, alters the oxidation pathway for FAOR over Pt catalyst and makes FAOR follow the more efficient dehydrogenation pathway. The density functional theory (DFT) calculation demonstrates that antimonene can activate Pt to be a lower oxidative state and facilitate the oxidation of HCOOH into CO2 via a direct pathway, resulting in a weakened intermediate binding strength and better CO tolerance for FAOR. The specific activity of FAOR on Pt/Sb is 4.5 times, and the mass activity is 2.6 times higher than the conventional Pt/C.

Highlights

Direct formic acid fuel cells (DFAFCs) have been considered as ideal electrochemical energy conversion devices [1, 2]
Pt-based catalysts have been widely used for formic acid oxidation reaction (FAOR) [3]
The bulk Sb was firstly treated by ball milling to obtain microcrystals (Figure S1)

Summary

Introduction

Direct formic acid fuel cells (DFAFCs) have been considered as ideal electrochemical energy conversion devices [1, 2]. The oxidation of formic acid on Pt catalysts often occurs through a dual pathway mechanism (i.e., dehydrogenation and dehydration pathway), which hinders the catalytic activity because of the poisoning of CO intermediates from the dehydration pathway [4, 5]. The 2D antimonene acts as the Pt support and cocatalyst for FAOR over Pt. The exfoliated Sb nanosheets have an ultrathin structure and can well anchor the in situ deposited Pt nanoparticles. According to the Bader charge analysis, there is a 0.24 jej charge transfer from antimonene to Pt, confirming the electronic interaction between Pt and Sb. the Sb cocatalyst can alter the oxidation pathway of formic acid over Pt catalyst and make FAOR prefer the more efficient dehydrogenation pathway. The specific activity of FAOR on Pt/Sb is 4.5 times and the mass activity is 2.6 times higher than Pt/C

Results and Discussion

Conclusions

Materials and Methods

Conflicts of Interest