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.

分散在氧化物载体表面的颗粒已在电催化、光催化和多相催化领域实现了广泛应用。然而，将纳米颗粒分散于氧化物本体中在合成上更具挑战性，因此研究较少，但这一策略或可开辟调控材料性质的新维度——类似于晶体晶格中离子的取代掺杂。本文展示了这样一种概念：可在钙钛矿氧化物（perovskite oxide）晶格内部及表面实现金属纳米颗粒的大规模可控生长，且颗粒间保持纳米级邻近度。通过采用原位操作技术（operando techniques），我们发现，在形成的纳米结构中，内源性纳米颗粒与钙钛矿晶格之间产生相互应变并无缝连接，从而增强了氧交换能力。此外，即使是深度嵌入的纳米颗粒，在表面颗粒存在的情况下，仍可与甲烷流可逆地交换氧，驱动甲烷氧化还原转化为合成气，且具有优异的选择性和长期循环稳定性。这些结果不仅例证了构建具有增强氧传输和存储能力的大规模自应变纳米结构的方法，还表明深度嵌入的氧化还原活性纳米颗粒可完全接触反应环境，驱动氧化还原转化，从而为设计支撑多种能源转换技术的材料提供了极具吸引力的新选择。