Search

[Display omitted] • Design of the prior PA-resistance electrocatalysts through theoretical calculation. • Discovery of different scaling relationship of the adsorption energy difference of O 2 and H x PO(3-x)- 4 on Pt 3 M(1 1 1) alloy surface. • Pt X Cu as the object for the research of internal mechanism of the potentially high PA resistance property. • Higher PA-resistance performance of Pt 2 Cu compared to the commercial PtC in half-cell and full-cell tests. In high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs), dissociative H 3 PO 4 in cathode will block the active sites of Pt-based electrocatalyst, which thus failure to catalyze the oxygen reduction reaction (ORR). Therefore, the electrocatalysts for the ORR in HT-PEMFCs with high resistance to H 3 PO 4 poisoning are significantly important. Due to the similar bonding structure between H x PO 4 3-x/O 2 and Pt (Pt-O), the design of catalysts which could selectively reduce the adsorption energy of the H 3 PO 4 is urgently needed. In this work, we screen proper H 3 PO 4 resistance electrocatalysts through theoretical calculation based on the adsorption energy difference between H x PO 4 3-x and O 2 as an evaluation criterion. Then, we prepared a series of Pt x Cu catalysts based on the theoretical calculation results and further studied the structure-performance relationship of phosphoric acid-resistant catalysts through combining physical property characterization and electrochemical tests including half-cell and single-cell. The mass activity of Pt 2 Cu/C is 0.51 A/mg Pt , exceeding the DOE's 2020 target of 0.44 A/mg Pt. After add 0.1 M H 3 PO 4 into the HClO 4 electrolyte, the half-wave potential (E 1/2) of Pt 2 Cu/C is only negatively shifted by 47 mV, much lower than 90 mV of TKK Pt/C. Furthermore, the HT-PEMFC with Pt 2 Cu/C in the cathode shows a peak power density of 383.4 mW/cm2, which surpasses that of TKK Pt/C for 231.0 mW/cm2. Our strategy of screening catalysts based on the adsorption energy difference study and further verified by experimental methods provides a promising strategy for the design of practical electrocatalyst in the cathode of HT-PEMFCs. [ABSTRACT FROM AUTHOR]

Atomically dispersed Fe-N-C catalyst is fabricated by a rational designed dual-MOFs strategy for efficient and low-cost DMFC application. • A dual-MOFs strategy is developed for the fabrication of atomically dispersed Fe-N-C catalyst. • The formation mechanism of the atomically dispersed Fe-N-C catalyst is well investigated. • The as-prepared catalyst demonstrates high ORR activity, excellent methanol tolerance and outstanding stability in acids. • The DMFC assembled with atomically dispersed Fe-N-C catalyst exhibits excellent performance. The rational design of highly efficient, low-cost and methanol-tolerant catalysts toward the oxygen reduction reaction (ORR) is urgently desired for the commercialization of direct methanol fuel cells (DMFCs). Herein, a novel Fe-N-C catalyst (ZIF/MIL-10-900) is derived from a mixture of ZIF-8 and MIL-101(Fe) and atomically dispersed FeN 4 structures are confirmed by Mössbauer spectra and X-ray absorption spectroscopy. Study on the pyrolysis procedure reveals that Fe atoms in FeN 4 are from MIL-101(Fe), while ZIF-8 acts as structural support and nitrogen sources. The as-prepared catalyst demonstrates a comparable ORR activity with the commercial Pt/C possessing a half-wave potential (E 1/2) of 0.78 V in acids, in combination with excellent methanol tolerance and stability. One of the highest peak power density of 83 mW cm−2 in DMFC (3 M CH 3 OH) by adopting ZIF/MIL-10-900 as cathode catalyst is obtained, which is 2.8-fold higher than that of the commercial Pt/C in the same operating condition. [ABSTRACT FROM AUTHOR]