Pore Modification and Phosphorus Doping Effect on Phosphoric Acid-Activated Fe-N-C for Alkaline Oxygen Reduction Reaction.

Jong Gyeong Kim,Sunghoon Han,Chanho Pak

doi:10.3390/nano11061519

Abstract

The price and scarcity of platinum has driven up the demand for non-precious metal catalysts such as Fe-N-C. In this study, the effects of phosphoric acid (PA) activation and phosphorus doping were investigated using Fe-N-C catalysts prepared using SBA-15 as a sacrificial template. The physical and structural changes caused by the addition of PA were analyzed by nitrogen adsorption/desorption and X-ray diffraction. Analysis of the electronic states of Fe, N, and P were conducted by X-ray photoelectron spectroscopy. The amount and size of micropores varied depending on the PA content, with changes in pore structure observed using 0.066 g of PA. The electronic states of Fe and N did not change significantly after treatment with PA, and P was mainly found in states bonded to oxygen or carbon. When 0.135 g of PA was introduced per 1 g of silica, a catalytic activity which was increased slightly by 10 mV at −3 mA/cm2 was observed. A change in Fe-N-C stability was also observed through the introduction of PA.

Highlights

The greenhouse effect and climate crisis have driven a transition in energy technology from fossil fuels to renewable energy [1,2,3]
Prior to the synthesis of Fe-N-C, the physical properties of SBA-15 used as a sacrificial template were characterized
Based on the scanning electron microscopy (SEM) image, the silica particles had an ovoid shape with a width and length of approximately 700 nm, and individual particles were separated without agglomeration (Figure 1a)

Summary

Introduction

The greenhouse effect and climate crisis have driven a transition in energy technology from fossil fuels to renewable energy [1,2,3]. Fuel cells, which are energy conversion devices with high efficiency and low emissions, have attracted immense interest in recent decades [4,5]. The sourcing of hydrogen, insufficient hydrogen storage technology, durability problems, and cost issues with noble metal catalysts, such as platinum, have hindered the commercialization of fuel cells [6,7]. The limitations have motivated several studies on lowering the cost of catalysts, which account for 41% of the manufacturing cost of fuel cells, at 500,000 systems per year [8,9]. Development of Pt-based alloys, low-loadings of platinum, modifications of the support, and alternative metal catalysts have been considered [10,11,12,13,14]

Methods

Results

Conclusion