Template-Directed Fabrication of Highly Efficient Metal–Organic Framework Photocatalysts

Abstract

Photocatalysis is a powerful and versatile tool widely applied in the areas of synthesis chemistry. However, most of the photocatalysts currently used are homogeneous catalysts, which inevitably face issues such as product–catalyst separation and recyclability. Addressing this challenge, we utilized a homogeneous Ru photocatalyst as a structure-directing template to fabricate a series of isostructural photocatalyst-encapsulating metal–organic frameworks (photocatalyst@MOFs) with high porosity, robustness, and photocatalyst loading. The regular channels of MOF can disperse the encapsulated photocatalysts, promote the mass transfer of substrates and products, and provide an outstanding substrate confinement effect, thereby dramatically improving the catalytic activity and excellent recyclability toward valuable organic reactions. For instance, the MOF photocatalysts can catalyze the asymmetric Mannich reaction with ketones with high yields and excellent enantioselectivities (up to 99% ee), better than the reported photocatalyst. Significantly, this was the first case that heterogeneous MOF-based photocatalyst can catalyze the asymmetric Mannich reaction without cocatalysts under room temperature and visible light. This work not only explores an avenue to prepare heterogeneous photocatalysts but also broadens the application scope of MOF-based photocatalysts.

An ultramicroporous multi-walled metal–organic framework for efficient C2H2/CO2 separation under humid conditions

“…1a), which is close to that of previously reported double-walled MOFs. [31][32][33] Three crystallographic independent In 3+ ions connect HCOO − ions to form a 1D helical chain (Fig. 1b).…”

Metal–Organic Framework‐Integrated Composites for Bone Tissue Regeneration

“…This method offers a range of notable advantages, including precise control over the size, shape, and crystallographic orientation of MOF crystals, as well as the ability to engineer MOFs with specific functional groups, enabling tailoring at the molecular level. [ 37 ] For example, in a recent breakthrough, a hollow‐structured In 2 O 3 @ZrO 2 heterostructure with abundant In 2 O 3 /ZrO 2 heterointerfaces was successfully derived from a MOF precursor, MIL‐68@UiO‐66, through template‐directed synthesis. This material exhibited superior activity and stability, achieving a significant methanol selectivity of 84.6% at a conversion rate of 10.4% for CO 2 hydrogenation to methanol.…”

Mesoporous Mixed-Metal–Organic Framework Incorporating a [Ru(Phen)3]2+ Photosensitizer for Highly Efficient Aerobic Photocatalytic Oxidative Coupling of Amines

“…The development and full use of clean energy have been an essential research focus in recent decades. − Among many clean energy sources, sunlight is considered one of the best natural sources, and the organic transformation driven by visible light has successfully converted solar energy into chemical energy. − Under visible light irradiation with sufficiently high energy, a series of photoactivated chemical reactions could occur accompanied by the initiation of complex free radical mechanisms, so photocatalysis is widely viewed as a route to the green synthesis of some chemicals due to its environmental friendliness and high sustainability. − As the critical component of photocatalysis, a variety of materials have been explored and researched to induce electron–hole separation and promote photocatalytic organic transformation. However, the most efficient and practical visible-light-driven photocatalysts are still based mainly on the soluble complexes of noble metals with strong light absorption, such as Ru and Ir. − Several strategies for the utilization of the noble metal-based photocatalysts, including designing novel Ru/Ir complex-based molecular photosensitizers via the change of the ligand structure, loading small molecular photosensitizers onto different solid materials via electric adsorption, doping or deposition, and post-modifying metal ions on the skeleton of porous materials by coordination, have been developed. ,− Yet many unavoidable problems have to be faced on account of nonrecoverability, nonrecyclability, and scarcity for some expensive homogeneous photocatalysts, but poor interface contacts between phases, inefficient charge separation and transportation, uncontrollable load capacity, and deleterious semiconductor degradation side reactions for some heterogeneous photocatalysts. − Moreover, most reported photocatalysts can only be used for a specific reaction rather than the multireaction platform. − Therefore, it remains a huge challenge to develop efficient, recyclable, stable, and versatile photocatalysts nowadays.…”