Designing efficient and stable oxygen evolution reaction (OER) catalysts is crucial for advancing water electrolysis technologies toward sustainable hydrogen production. Ruthenium pyrochlore oxide (A2Ru2O7−δ) has attracted much attention due to its high OER catalytic activity and low cost. However, their catalytic activity and stability require further improvement to achieve commercial viability. In this study, a series of Pt-deposited Yttrium ruthenate (Y2Ru2O7−δ, YRO) bifunctional catalysts Pt(x%)-Y2Ru2O7 were prepared by hydrothermal and heat treatment methods. In an acidic environment, the OER activity and stability were significantly improved compared with YRO, and hydrogen evolution reaction (HER) performance gradually improved. Among them, Pt(25%)-YRO showed excellent OER (η10 = 260 mV, 43.1 mV dec−1) and HER (η10 = 120 mV, 51.2 mV dec−1) performance. In addition, Pt(25%)-YRO demonstrated excellent catalytic stability, with both the OER and the overall water splitting reaction maintaining stable operation at 10 mA cm−2 for over 50 h. This provides a new approach for developing high-activity, high-stability, dual-function water electrolytic catalysts for use in harsh acidic environments.
Qingren Zhang,Tongtong Liu,Hengyu Guo,Yanan Chen,Yajing Di,Zhengping Zhang,Feng Wang
Pyrochlore ruthenates are highlighted as candidates to replace iridium oxide as oxygen evolution reaction (OER) electrocatalyst, but their designable geometric configurations and composition modulations are hampered by the high-temperature (≈1100 °C) and long-time calcination (more than 12 h), which further decreases the technical and economic feasibility. In this work, an energy- and time-saving approach is proposed to prepare pyrochlore yttrium ruthenate at a much lower calcination temperature (600 °C) and shorter calcination time (6 h) just by inducing A-site substitutions of lead ions (YPRO). The local microstrain derived from Pb provides the surficial compression and extra driving force to overcome the strain energy of phase-transition resistances and the obtained low-temperature YPRO exhibits enriched pores, deficient geometries, shortened Ru─O bond, and enlarged Ru─O─Ru bond angle, which further modify the electronic structure, involving of the rearranged band alignment and the eliminated bandgap. The regulated morphologic, geometric, and electronic structures in YPRO synergically boost the electrocatalytic OER performance (4.8-fold and 30.0-fold enhancements compared with pyrochlore yttrium ruthenate and commercial iridium dioxide (IrO 2 ), respectively) in universal pH conditions. This substitution-induced strain engineering on phase transition should also be effective for other high-temperature materials and trigger their diverse intriguing properties.
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