Turnover Frequency of Catalyst: Unveiling the Secrets of Supramolecular Photocatalysts

The quest to develop efficient and sustainable methods for reducing carbon dioxide (CO2) has led to significant breakthroughs in the field of supramolecular photocatalysis. In recent years, researchers have made tremendous progress in designing and synthesizing novel supramolecular structures that can selectively photocatalyze the reduction of CO2 to formic acid with high efficiency.

One such approach involves the use of supramolecules composed of a 2+ (N ∧N = a diimine ligand)–type complex as a photosensitizer and a Re(I) diimine complex as a catalyst. This unique architecture has been shown to enable the photocatalytic formation of formic acid through two sequential processes: the photochemical reduction of the photosensitizer unit by NADH model compounds and intramolecular electron transfer to the catalyst unit.

The advantages of this approach are evident in the results obtained with various supramolecules. For instance, a trinuclear complex featuring two photosensitizer units and one catalyst unit has been found to photocatalyze CO2 reduction at an unprecedented rate, yielding formic acid with a turnover frequency (TOF) of 11.6 min-1.

Interestingly, the ratio of the photosensitizer unit to the catalyst unit plays a crucial role in determining the yield of formic acid. By increasing the proportion of the photosensitizer unit, researchers have been able to enhance the reaction rate and selectivity, ultimately leading to higher yields of formic acid.

In addition to their efficiency, these supramolecules also exhibit exceptional durability, allowing them to operate effectively over a wide range of wavelengths of visible light and with various NADH model compounds as electron donors. The potential applications of these novel supramolecular photocatalysts are vast, from the development of sustainable energy sources to the mitigation of climate change.

In summary, the turnover frequency of catalysts in supramolecular photocatalysis has been shown to play a critical role in determining the efficiency and selectivity of CO2 reduction reactions. By optimizing the ratio of photosensitizer units to catalyst units, researchers have been able to design and synthesize novel supramolecules that can photocatalyze the reduction of CO2 with unprecedented rates and yields. As this field continues to evolve, we can expect to see even more innovative applications of these powerful photocatalysts in the years to come.

Turnover frequency of catalyst