Speaker
Description
Due to the ongoing global warming and the upcoming energy crises, the exploitation of alternative, renewable energy sources has become a major focus of materials chemistry. The ultimate solution for sustainable energy lies in the concept of solar fuels – commodity chemicals that can be generated from nothing but sunlight and abundant feedstock through heterogeneous photocatalysis. The reactions of water splitting and carbon dioxide photoreduction, however, involve complex multi-electron redox processes that require a rational design of the surface catalytic sites. When working with ill-defined inorganic surfaces, these sites are inevitably hard to study and understand on a truly fundamental level, which limits the development of active and selective photocatalysts.
Homogeneous photocatalysis has developed largely independently from its heterogeneous counterpart and has achieved greater success in the rational design of organometallic photocatalysts, largely due to principles derived from coordination chemistry. Nevertheless, molecular photocatalysts encounter distinct limitations, including inadequate redox stability and the requirement for an additional molecular photosensitizer to facilitate light absorption.
In this talk, I will demonstrate that a rational integration of both photocatalytic approaches can address their respective limitations and contribute to bridging the gap between the two communities. As prime examples of this combination, we employ a diverse set fully-inorganic molecular clusters as surface-immobilized co-catalysts for photocatalytic water splitting reactions.[1-3] First, I will discuss covalent attachment of an anionic thiometalate cluster ([Mo3S13]2-) to the photoactive TiO2 surface for photocatalytic hydrogen evolution.[4] Second, I will present two exemplary POMs anchored onto TiO2 via linker-mediated electrostatic binding for photocatalysis.[5] In-depth characterization will unravel details of cluster immobilization, structural integrity and molecular nature of the attachment. Finally, photocatalytic experiments coupled with mechanistic studies will shed light on their stability, active sites, and long term performance.
References:
[1] A. Cherevan et al., Advanced Science 2020, 7 (8), 1903511.
[2] S. Batool et al., Advanced Materials 2024, 36, 2305730
[3] ACS Nano 2026, 20, 1, 99–118
[4] S. Batool et al., ACS Catalysis 2022, 12, 6641–6650
[5] S. Nandan et al., ACS Materials Au 2022, 4, 505–515