Abstract：
This study investigated the redox exsolution of Ni nanoparticles from a nanoporous La0.52Sr0.28Ti0.94Ni0.06O3 perovskite. The characteristics of exsolved Ni nanoparticles including their size, population, and surface concentration were deeply analyzed by environmental scanning electron microscopy (ESEM), transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDX) mapping, and hydrogen temperature-programmed reduction (H2-TPR). Ni exsolution was triggered in hydrogen as early as 400 °C, with the highest catalytic activity for low-temperature CO oxidation achieved after a reduction step at 500 °C, despite only a 10% fraction of Ni exsolved. The activity and stability of exsolved nanoparticles were compared with their impregnated counterparts on a perovskite material with a similar chemical composition (La0.65Sr0.35TiO3) and a comparable specific surface area and Ni loading. After an aging step at 800 °C, the catalytic activity of exsolved Ni nanoparticles at 300 °C was found to be 10 times higher than that of impregnated ones, emphasizing the thermal stability of Ni nanoparticles prepared by redox exsolution.
摘要：
这项研究研究了纳米多孔La0.52Sr0.28Ti0.94Ni0.06O3钙钛矿中Ni纳米颗粒的氧化还原溶液。溶解镍纳米颗粒的特性，包括它们的尺寸，人口,通过环境扫描电子显微镜（ESEM）对表面浓度进行了深入分析，透射电子显微镜-能量色散X射线光谱(TEM-EDX)作图,和氢气程序升温还原（H2-TPR）。镍溶液早在400°C时就在氢气中触发，在500°C的还原步骤后，对低温CO氧化具有最高的催化活性，尽管只有10%的镍溶解。在具有相似化学组成（La0.65Sr0.35TiO3）以及可比的比表面积和Ni负载量的钙钛矿材料上，将溶解的纳米颗粒的活性和稳定性与其浸渍的对应物进行了比较。在800°C下进行老化步骤后，发现溶解的Ni纳米颗粒在300°C下的催化活性比浸渍的纳米颗粒高10倍，强调氧化还原溶液制备的Ni纳米颗粒的热稳定性。
