Doping‐Modulated Strain Enhancing the Phosphate Tolerance on PtFe Alloys for High‐Temperature Proton Exchange Membrane Fuel Cells

Abstract

In high‐temperature proton exchange membrane fuel cells (HT‐PEMFCs), the poisoning of Pt by phosphoric species severely affects the kinetics of the oxygen reduction reaction, which restricts their commercialized application. Herein, for the first time, the phosphate tolerance of PtFe ordered intermetallic alloys is enhanced by a doping‐modulated strain strategy via employing a low amount of Cu as a dopant to boost HT‐PEMFCs. This Cu doping facilitates the formation of compressive strain in PtFe crystals, consequently altering the electronic structure of electrocatalysts and then benefiting for weakening the adsorption energy between phosphoric acid and Pt surfaces. In addition, the high temperature phosphate adsorption tests also reveal that the dopant of Cu in Pt based electrocatalysts can improve the tolerance of phosphoric acid. The HT‐PEMFCs assembled by those cathodic electrocatalysts with the low‐Pt loading of 0.5 mgPt cm−2 achieve a preeminent peak power of 793.5 and 432.6 mW cm−2 under the condition of H2–O2 and H2–air atmosphere, respectively, or nearly 1.53 and 1.34 times higher as compared with commercial Pt/C electrocatalysts. Moreover, those electrocatalysts also exhibit robust stability under harsh condition in H2–O2 atmosphere with negligible activity loss for at least 100 h, exceeding most of other reported ORR electrocatalysts.

Oxygen vacancies engineering in electrocatalysts nitrogen reduction reaction

“…Heterogeneous ion doping is based on the difference in the electronegativities of intrinsic atoms, and is used to introduce defects into crystal structures and adjust the physicochemical properties of materials ( Li W et al, 2020 ; Li et al, 2022a ). For pure oxygen-containing compounds, both metallic and nonmetallic doping can create an imbalanced charge atmosphere that tends to break the long-term periodicity of the lattice oxygen in the oxide; thus, OVs are formed to maintain thermodynamic stability.…”

Recent advances in the design of single-atom electrocatalysts by defect engineering

“…In addition to adjusting the coordination structure of single metal atoms, heteroatom doping can also regulate the electronic structure of single metal atom-based active sites. Li and co-workers synthesized Cu or Fe single atom anchored on an S, N-codoped carbon basal plane by a defect trapping strategy ( Figure 1B ) ( Li et al, 2021a ). Both Raman spectra and electron paramagnetic resonance (EPR) spectroscopy displayed that S-doping created numerous defects in NSC compared to that in NC.…”

“…At present, increasing attention is being devoted to electrochemical energy conversion and storage (e.g., fuel cells, water-splitting devices, storage batteries, artificial carbon, and nitrogen fixation) due to their high energy densities and environmental benefits ( Wang et al, 2019 ; Ai et al, 2021 ; Chen et al, 2021 ). The operation of all of these technologies requires appropriate advanced electrocatalysts to reduce the energy barriers and accelerate the kinetics of chemical reactions, such as the hydrogen oxidation reaction (HOR), oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), oxygen evolution reaction (OER), nitrogen reduction reaction (NRR), carbon dioxide reduction reaction (CO 2 RR), biomass oxidation reaction, and so on ( Jiang et al, 2020 ; Zhou et al, 2020 ; Li et al, 2021a ; Wang et al, 2022b ; Wang et al, 2022c ; Zhu et al, 2022 ). Accordingly, the state-of-the-art catalysts mainly depend on platinum group metals (PGMs, Pt, and Au), PGM-based oxides (IrO 2 and RuO 2 ), and PGM-based alloys (PtRu and PtPd) ( Li et al, 2022 ; Yan et al, 2022 ; Zhao et al, 2022 ).…”

Ordered intermetallic compounds combining precious metals and transition metals for electrocatalysis

“…More and more people are beginning to pay attention to the influence of changes in the content of intermetallic compounds on the activity and stability of materials during the ORR reaction. ( Zhu et al, 2018a ; Zhu et al, 2018b ; Li et al, 2022 ).…”