Critical Properties for Stabilizing Pd Nanoparticles in Graphene Oxide Framework-Supported Catalysts: Insights from Multifaceted Characterization.

Graphene oxide frameworks (GOFs) have great potential as supports for metal nanoparticle (NP) catalysts due to their advantageous properties, such as engineerable pores. Since GOFs are prepared by bridging GO sheets with linker molecules, their properties depend on the GO raw material, and thus, designing guidelines for GOs is important but has not been established yet. The most significant obstacle is the diversity of the physicochemical properties of GOs, making it difficult to determine which properties are linked to their performance as catalyst supports. To address this issue, we synthesized GOFs from three GOs with different properties, loaded them with Pd NPs, and evaluated their catalytic performance in the Suzuki-Miyaura reaction. Using a multifaceted characterization approach, we found the following facts: The amount of linker molecules in the GOFs, and thus, the number of reactive functional groups in the GOs to anchor the linker molecules, are vital for the stabilization of Pd NPs. Therefore, to obtain highly dispersed and recyclable Pd NP catalysts, it is important to synthesize the raw GO materials at the site and convert them to GOFs as freshly as possible under mild conditions. Although GOFs have been demonstrated to be useful for various applications, the importance of the quality of the raw material, GO, has sometimes been overlooked. The approach presented in this study, which assesses the quality of GOs using a multifaceted method, is likely to be valuable for fundamental research and the enhancement of performance in all GOF materials.