Endogenous Nanoparticles Strain Perovskite Host Lattice Providing Oxygen Capacity and Driving Oxygen Exchange and CH4 Conversion to Syngas

Particles dispersed on
the surface of oxide supports have enabled a wealth of applications in electro-
photo- and heterogeneous catalysis. Dispersing nanoparticles within the bulk of
oxides is, however, synthetically much more challenging and therefore less
explored, but could open new dimensions to control material properties
analogous to substitutional doping of ions in crystal lattices. Here we
demonstrate such a concept allowing extensive, controlled growth of metallic
nanoparticles, at nanoscale proximity, within a perovskite oxide lattice as well
as on its surface. By employing operando techniques, we show that in the
emergent nanostructure, the endogenous nanoparticles and the perovskite lattice
become reciprocally strained and seamlessly connected, enabling enhanced oxygen
exchange. Additionally, even deeply
embedded nanoparticles can reversibly exchange oxygen with a methane stream,
driving its redox conversion to syngas with remarkable selectivity and long
term cyclability while surface particles are present. These results not only
exemplify the means to create extensive, self-strained nanoarchitectures with
enhanced oxygen transport and storage capabilities, but also demonstrate that
deeply submerged, redox-active nanoparticles could be entirely accessible to
reaction environments, driving redox transformations and thus offering
intriguing new alternatives to design materials underpinning several energy
conversion technologies.

氧化载体表面的分散颗粒，为电光及非均相催化领域带来了丰富的应用。然而，将纳米颗粒分散于氧化物本体中在合成上显得尤为艰巨，因而研究较少，但这一领域有望开辟出控制材料性能的新维度，类似于在晶体格子中通过离子掺杂进行替代掺杂。在本研究中，我们展示了一种概念，允许在钙钛矿氧化物晶格内部及其表面实现金属纳米颗粒的广泛、可控生长。通过原位技术，我们揭示了在形成的纳米结构中，内源纳米颗粒与钙钛矿晶格相互施加应变并无缝连接，从而增强了氧的交换能力。此外，即使深层嵌入的纳米颗粒也能与甲烷流可逆地交换氧，推动其氧化还原转化生成合成气，表现出显著的选择性和长期循环稳定性，而表面颗粒的存在则进一步强化了这一特性。这些成果不仅展示了创建具有增强氧传输和储存能力的广泛、自应变纳米结构的方法，而且证明了深层沉没的氧化还原活性纳米颗粒可以完全暴露于反应环境中，驱动氧化还原转化，从而为设计支撑多种能量转换技术的材料提供了引人入胜的新选择。