The visible‐light‐driven hydrogen evolution reaction (HER) by covalent photosensitizer–catalyst dyads is one of the most elegant concepts in supramolecular homogeneous solar energy conversion. The intricacies of catalyst reactivity and photosensitizer–catalyst interactions require a detailed fundamental understanding of the system to rationalize the observed reactivities. Here, we report three dyads based on the covalent imine‐bond linkage of an iridium photosensitizer and an organo‐functionalized Anderson polyoxometalate anion [MMo6O18{(OCH2)3CNH2}2]3− (M=Mn3+, Fe3+, Co3+). Modification of the central metal ion M is used to modulate the HER activity. Detailed theoretical and experimental studies examine the role of the central metal ion M and provide critical understanding of the redox activity and light‐driven HER activity of the novel dyads. Thus, the study enables a knowledge‐based optimization of HER dyads by chemical modification of the reactive metal oxide components.
Solar hydrogen evolution from water is a necessary step to overcome the challenges of rising energy demand and associated environmental concerns. Low-cost photocatalytic architectures based on polymeric light absorbers coupled...
Reproducibility and comparability of photocatalytic experiments are still challenging, owing to the large number of experimental parameters and their comprehensive documentation. To overcome this limitation, a modular, adaptable, and extensible photoreactor platform is reported, which enables experiments under well‐characterized, reproducible conditions. Comparability is ensured by comprehensive photonic characterization with chemical actinometry, radiometry and open documentation of the incident photon fluxes in the reaction vessels for different setups as well as the homogeneity of irradiation in multi‐reactor setups. Comprehensive documentation minimizes the need for repeated photonic characterization when modifying the setups. Experimental reproducibility within and across experiments was evaluated with studies of photocatalytic systems for hydrogen evolution, emphasizing the validity of the concept.
An effective strategy to enhance the performance of inorganic semiconductors is moving towards organic‐inorganic hybrid materials. Here, we report the design of core–shell hybrid materials based on a TiO2 core functionalized with a polyampholytic (poly(dehydroalanine)‐graft‐(n‐propyl phosphonic acid acrylamide) shell (PDha‐g‐PAA@TiO2). The PDha‐g‐PAA shell facilitates the efficient immobilization of the photosensitizer Eosin Y (EY) and enables electronic interactions between EY and the TiO2 core. This resulted in high visible‐light‐driven H2 generation. The enhanced light‐driven catalytic activity is attributed to the unique core–shell design with the graft copolymer acting as bridge and facilitating electron and proton transfer, thereby also preventing the degradation of EY. Further catalytic enhancement of PDha‐g‐PAA@TiO2 was possible by introducing [Mo3S13]2− cluster anions as hydrogen‐evolution cocatalyst. This novel design approach is an example for a multi‐component system in which reactivity can in future be independently tuned by selection of the desired molecular or polymeric species.
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