Ex‐Solved Ag Nanocatalysts on a Sr‐Free Parent Scaffold Authorize a Highly Efficient Route of Oxygen Reduction

Abstract

The electrocatalytic value of nanoparticles has attracted substantial attention in relation to energy conversion devices, including solid oxide fuel cells. Among various forms of analogs, ex‐solved metal nanoparticles originating from their parent oxides display strong particle‐substrate interactions and thus have the benefits of extended durability and of course enhanced catalytic activity. Inspired by recent advances, here, novel air‐electrode materials based on BaCoO3–δ perovskites decorated with socketed Ag nanoparticles are presented. Doping with niobium (Nb5+) and tantalum (Ta5+) can significantly promote the stability of the cubic perovskite phase. The developed oxides exhibit promising performance outcomes in the highly prized low‐to‐intermediate temperature regimes (450–650 °C). Moreover, the exclusion of Ag particles further activates the parent scaffold, thereby conveying record‐level area‐specific resistance (e.g., ≈0.02 Ω cm2 at 650 °C). Coupled with the unique nanoarchitecture, the newly designed cathode showcases in this study hold great promise for future air‐electrodes in fuel cells.

Self-assembled nano-composite perovskites as highly efficient and robust hybrid cathodes for solid oxide fuel cells

“…4b). 8,19,23,24,30 A subsequent ASR stability test also demonstrated a stable behavior, highlighting the feasibility of the developed material for practical operation (Fig. S15†).…”

“…Formulating nanoscale composite electrodes has important merits, as the better homogeneity of mixing can expand the effective cathodic reaction regions, leading to a superior activity. [18][19][20][21][22] Moreover, nano-structured materials endorse high porosities advantageous to the efficient gas transport. Hence, a method to obtain nano-composites is highly desirable, however oen these methods are time-consuming or accompany highly energyintensive processes, which are not practically applicable in large-scale.…”

Emergence and Future of Exsolved Materials

“…[151] Similar to the Ru materials discussed above, when applied for ORR, exsolved Ag nanoparticles are reported be "extraordinarily" stable and serve as both active reaction sites and prime electron-transfer pathways while providing strong anchoring, effectively mitigating the known instability of Ag. [69,71,152,153] Last, decoration of NH 3 sensor electrodes with Ag nanoparticles has been reported to enhance the response signal (electric potential difference) of the sensor accompanied by improved sensitivity, and detection limit as well as outstanding selectivity to NH 3 against NO 2 . The anti-interference capability of the sensor toward NO and NO 2 is effectively enhanced due to the improved adsorption and electrocatalytic activity of the materials.…”

Nanoparticle Ex-solution for Supported Catalysts: Materials Design, Mechanism and Future Perspectives

“…Typically, perovskites are prepared via a solid-state reaction or a solgel method. 142,143 During the synthesis process, high-temperature calcination (e.g., > 900 °C) is conducted to ensure cation blending and phase purity. Hence, the surface area of the perovskite support is usually less than 10 m 2 /g.…”