Controlled Growth of a Photocatalytic Metal–Organic Framework on Conductive Plates by Mixing Direct Synthesis and Postsynthetic Modification Strategies

Abstract

In this work, we develop a two-step process for the controlled growth of a thin layer of a functionalized and photosensitive metal–organic framework (MOF), namely Ru–Ti–UiO-67, on the surface of a plate coated with indium tin oxide (ITO), a transparent conductive oxide (TCO). In the first step, the in situ controlled growth of a layer of UiO-67-based MOF doped with a photosensitizer (ruthenium complex), herein referred to as Ru–UiO-67, is carried out on the surface of the ITO-coated plate, leading to Ru–UiO-67/ITO. The obtained MOF layer is relatively thin, allowing increased interactions between the MOF material and the TCO surface, and consists of crystals in the near-nanometer particle size. In the second step, a postsynthetic modification (PSM) process is applied to Ru–UiO-67/ITO to integrate Ti catalytic sites into the MOF framework, leading to Ru–Ti–UiO-67/ITO (containing both the photosensitizer and catalyst) while maintaining the MOF’s structure and morphology in addition to its strong interaction with the substrate. Importantly, on the synthetic level, this work demonstrates the possibility to form a homogeneous surface anchored with MOF on a transparent conductive surface, whereby the obtained MOF layer is strongly bound to the substrate and postsynthetic chemical modifications are enabled without any loss of material. Furthermore, the obtained material is proven to exhibit an efficient visible-light-driven photodegradation activity in aqueous solution.