Juan Zhou

Proton ceramic fuel cells (PCFCs) have emerged as promising next-generation energy conversion devices operating at intermediate temperatures (400-750 °C). The insufficient catalytic activity of oxygen electrodes at intermediate temperatures largely restricts their practical application. It is therefore urgent to develop high-performance oxygen electrodes with excellent ORR catalytic activity and long-term operational durability. In this work, a series of Sr2-xCaxFe1.5Mo0.5O6-δ (SCaxFM, x = 0, 0.2, 0.3, 0.4) double perovskite nanofibers were synthesized via electrospinning and comprehensively evaluated as PCFC oxygen electrodes. Anode-supported single cells with SCa30FM oxygen electrode deliver a peak power density of 652.17 cm-2 at 750 °C, representing an 84% improvement over undoped SFM (353.59 mW cm-2), with exceptional operational stability over 100 hours at 400 mA cm-2 and 650 °C. This work demonstrates that SCa30FM nanofibers represent a highly promising cobalt-free oxygen electrode material for intermediate-temperature PCFCs.

Proton-conducting solid oxide fuel cells (PCFCs) represent a promising class of energy conversion technologies operating at intermediate to low temperatures. However, the development of efficient oxygen reduction reaction (ORR) catalysts remains a critical challenge for achieving practical performance in PCFCs. In this study, a series of K-doped Sr₂Fe_1.5Mo_0.5O_6-δ (SFM) perovskites with triple-conducting characteristics, synthesized through electrospinning into a nanofiber architecture, are presented as high-performance oxygen electrode materials. The SK30FM electrode demonstrates exceptional electrochemical performance, exhibiting a low polarization resistance of 0.062 Ω cm² under wet air (3% H₂O) at 750 °C, and delivering a peak power density of 645 mW cm^-2 with decent short-term stability during fuel cell operation. These results highlight the significant potential of SFM-based perovskites as advanced oxygen electrodes for PCFCs, while also underscoring the advantages of electrospinning in fabricating nanostructured functional materials.

Anion exchange membrane fuel cells (AEMFCs) represent a promising class of clean energy devices, with their performance being critically dependent on the efficiency of the cathode oxygen reduction reaction (ORR) catalyst. Manganese-cobalt spinel (Mn_1.5Co_1.5O₄, MCS) has been demonstrated to be a highly active ORR catalyst. Herein, we report a strategy of incorporating Cu (MCCS) and Fe (MCFS) into MCS to form ternary spinel oxides for tuning ORR activity. Among them, MCS exhibits the best ORR performance, with a half-wave potential (E_1/2) of 0.736 V vs. RHE in 0.1 M KOH and a peak power density (PPD) of 248.3 mW·cm⁻² for the fuel cell test. In contrast, MCCS and MCFS show divergent behaviors in a rotating disk-ring electrode (RRDE) and fuel cell tests. X-ray diffraction (XRD) analyses and X-ray photoelectron spectroscopy (XPS) analyses reveal that the introduction of Cu²⁺ and Fe³⁺ induces a phase transformation in the spinel structure, leading to a reduction in oxygen vacancies and an increase in the valence state of Mn, thereby degrading catalytic activity. However, the incorporation of these elements also modulates the hydration capability of the catalysts, which is critical for the ion and charge transfer in the fuel cell environment and has been validated in the distribution of relaxation time (DRT) analysis of the fuel cell test. This study provides a valuable strategy for designing and synthesizing low-cost, highly efficient, and stable ternary spinel electrocatalysts for AEMFC applications, and bridges the gap between RRDE evaluation and fuel cell testing through DRT analysis.

Ultrathin core–shell Au@RuNi nanowires have been synthesized via the epitaxial growth of uniform fcc -structured RuNi alloy layer on the surface of ultrathin Au NWs, demonstrating remarkable alkaline HER performance and outstanding stability.

The rational structural and compositional design of Pt-based electrocatalysts is effective in synergizing the physicochemical and electrochemical properties of Pt for developing high-performance hydrogen evolution reaction (HER) electrocatalysts. In this study, we present the synthesis of one-dimensional (1D) Au@PtPd@Pt nanowires using a template-induced method. The nanowires are composed of ultrathin PtPd alloy layers coated on the surface of Au nanowires (NWs) and ultrafine island-like Pt nanoparticles grown on the surface of a PtPd alloy shell. The resulting Au@PtPd@Pt nanowires exhibit exceptional electrocatalytic activity and excellent long-term electrochemical stability toward the alkaline HER, which is attributed to the synergistic effect of the anisotropic ultrathin 1D nanowires with a prominent core–shell–satellite structure and the trimetallic elemental compositions. The nanowires demonstrate a low overpotential of 23 mV at 10 mA cm⁻², outperforming commercial Pt/C, and bimetallic counterparts. Additionally, the integrated Au@PtPd@Pt//RuO₂ electrolyzer achieves a lower operating potential of 1.52 V to achieve 10 mA cm⁻², surpassing the performance of the commercial Pt/C//RuO₂ configuration. This highlights its great potential for practical water electrolysis. This work showcases an effective design approach that comprehensively and rationally considers both the designed nanostructure and multiple compositions to achieve high-performance electrocatalysts for various electrochemical reactions.