Wei Peng

Bio: Wei Peng is an academic researcher from Donghua University. The author has contributed to research in topics: Cobalt fluoride & Bimetallic strip. The author has an hindex of 1, co-authored 1 publications receiving 12 citations.

Facile Synthesis of Bimetallic Fluoride Heterojunctions on Defect-Enriched Porous Carbon Nanofibers for Efficient ORR Catalysts.

Abstract: The development of efficient and stable catalysts for the oxygen reduction reaction (ORR) at low cost is crucial for realizing the large-scale application of metal-air batteries. Herein, we report an efficient ORR catalyst of bimetallic copper and cobalt fluoride heterojunctions, which are uniformly dispersed in nitrogen-fluorine-oxygen triply doped porous carbon nanofibers (PCNFs) that contain hierarchical macro-meso-micro pores. The composite catalyst materials are fabricated with a facile and green method of electrospinning with water as the solvent. By using poly(tetrafluoroethylene) as the pore inducer to anchor electropositive copper and cobalt salts in the electrospun hybrid nanofibers, bimetallic fluoride heterojunctions can be directly formed in PCNFs after calcination. The hierachical porous structures provide an effective way to transport matter, while the bimetallic fluorides expose abundant electroactive sites, both of which result in stable ORR activities with a high half-wave potential of 0.84 V. The study proposes a feasible strategy for the fabrication of nonprecious catalysts.

Recent advances in the design of a high performance metal–nitrogen–carbon catalyst for the oxygen reduction reaction

Abstract: Developing highly active, stable, and cost-effective cathode oxygen reduction reaction (ORR) catalysts is of great practical significance to promote the widespread applicability of fuel cells (FCs). Recent studies have witnessed remarkable progress in exploring the synthesis of high-performance ORR catalysts. Platinum group metal (PGM)-free catalysts with metal–nitrogen–carbon (M–N–C) sites are considered to be promising candidates for ORR catalysts due to their low cost and good applicability to multiple ORR steps. Here, we provide a focused discussion on the design strategies of high-efficiency M–N–C catalyst synthesis from the aspects of increasing active site density, improving intrinsic activity, facilitating mass transfer and avoiding the linear scaling relationship (LSR). The synthesis of M–N–C single-atom catalysts opens up a new way to increase active site density. The selection of an appropriate central metal and coordination atom as well as the adjustment of the local coordination environment are very crucial to enhance catalyst intrinsic activity. The reasonable design of a porous structure is an important prerequisite to promote mass transfer and build the largest three-phase interface. The development of new active sites makes it possible to avoid the LSR and prepare catalysts with ultra-low overpotential. Furthermore, the main mechanisms causing the rapid degradation of M–N–C catalyst activity, such as active site demetallization, H2O2 hazards and flooding problems, are discussed, and effective mitigation strategies are proposed to improve the M–N–C catalyst stability. Ultimately, the designs of high performance M–N–C catalysts for the ORR are summarized and prospected.

Tuning d‐Band Center of Pt by PtCo‐PtSn Heterostructure for Enhanced Oxygen Reduction Reaction Performance

Abstract: The development of efficient and stable Pt-based catalysts is significant but challenging for fuel cells. Herein, Sn and Co elements are introduced into Pt to form PtCo-PtSn/C heterostructure for enhancing the oxygen reduction reaction (ORR). Electrochemical results indicate that it has remarkable ORR intrinsic activity with a high mass activity (1,158 mA mg-1 Pt) at 0.9 V in HClO4 solution, which is 2.18-, 6.81-, and 9.98-fold higher than that of PtCo/C, PtSn/C, and Pt/C. More importantly, the catalytic activity attenuation for PtCo-PtSn/C is only 27.4% after 30 000 potential cycles, showing high stability. Furthermore, theoretical calculations reveal that the enhancement is attributed to charge transfer and the unique structure of PtCo-PtSn/C heterostructure, which regulate the d-band center of Pt and prevent non-noble metals from further dissolution. This work thus opens a way to design and prepare highly efficient Pt-based alloy catalysts for proton exchange membrane fuel cells.