Revisiting the Incorporation of Ti(IV) in UiO-type Metal–Organic Frameworks: Metal Exchange versus Grafting and Their Implications on Photocatalysis

Abstract

The inclusion of Ti(IV) in water-stable metal-organic frameworks has been proposed as a strategy for the generation of high surface area heterogeneous photocatalysts, with UiO-66 being a promising candidate. We find that the site of binding of Ti(IV) is at linker defect sites and not incorporated into the inorganic secondary building unit through metal exchange. We also demonstrate the choice of titanium source is critical in the generation of an active hydrogen evolution catalyst, and explain the observed activity using density functional theory calculations, which also enable rational design of future Ti(IV) coordination environments in MOF catalysts.

Synthesis of heterometallic metal–organic frameworks and their performance as electrocatalyst for CO2 reduction

“…16 Despite the details described above, this indicates that the dopant is incorporated into the SBU of the MOF, but we cannot disregard that part of the dopant might also be appended as a defect in the surface of the framework. 20 Accordingly, a reduction in the surface area and micropore volume might be expected, but a similar effect can also be attributed to the slight modications of the synthetic conditions (such as a change in the starting reagents). When considering the PXRD analysis, it must be pointed out that despite the fact that solventless synthesis has been demonstrated to be a suitable procedure to incorporate dopants into MOFs, 21 the method is quite sensitive to the handmilling and heating procedure and as a result, it can produce some batches with some minor crystalline impurities in the products (Fig.…”

Mixed‐Metal MOFs: Unique Opportunities in Metal–Organic Framework (MOF) Functionality and Design

“…Minireviews success of the nodal Zr-by-Tie xchange and it was proposed that the Ti IV species become attached to linker vacancies in the structure. [83] Further exhaustive characterization appears pertinent to clarify the conditions for ar eal post-synthetic nodal metal ion exchange. Interestingly,d uring the partial metal exchange in MOF crystals,acore-shell MM-MOF structure can be formed because that metal replacement proceeds from the crystal surface towards the core ( Figure 12).…”

Mixed‐Metal MOFs: Unique Opportunities in Metal–Organic Framework (MOF) Functionality and Design

“…Kurzaufsätze success of the nodal Zr-by-Tie xchange and it was proposed that the Ti IV species become attached to linker vacancies in the structure. [83] Further exhaustive characterization appears pertinent to clarify the conditions for ar eal post-synthetic nodal metal ion exchange. Interestingly,d uring the partial metal exchange in MOF crystals,acore-shell MM-MOF structure can be formed because that metal replacement proceeds from the crystal surface towards the core ( Figure 12).…”