EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

With the increasing energy demand, the replacement of unsustainable fossil fuels with renewable sources of energy is desperately needed. Solar fuels, such as hydrogen (H2) are one of the most promising alternative energy sources. The ample supply of water and sunlight on earth makes hydrogen generation via the photo-catalytic water splitting reaction a viable source. Although the earth receives a huge amount of solar energy every hour, it is fluctuant (i.e. depending on the location and time) and rather low in density. Therefore, the development of a photocatalytic system that efficiently uses solar irradiation to produce hydrogen fuel is important.
Heterogeneous photo-catalysis, in which a semiconducting catalyst is dispersed in water, can generate hydrogen upon shining light with a greater energy than the semiconductor band gap. Despite the simplicity and scalability, this particulate system suffers from several drawbacks. The photocatalyst particles often tend to agglomerate thereby, decreasing the surface area and increasing the charge carrier diffusion length, leading to lower photocatalytic activity. Thin-films are a suitable strategy to overcome these challenges as it provides the advantages of easy catalyst recovery and incorporation into electrochemical systems. This opens up the possibility to better understand the system via electrochemical characterization techniques.
In this work, we design a protocol for the assembly of thin film photocatalyst, from materials such as TiO2, BiVO4, WO3 etc., covering a wide range of the electromagnetic spectrum. We then study them for the heterogeneous photocatalytic Hydrogen evolution reaction using non-noble metal co-catalysts such as a series of promising MoSx molecular clusters. We further investigate the reaction mechanism via several photo- and electro-chemical techniques to understand the synergistic effects between the catalytic components. This understanding would provide further insight into the photo-catalytic processes and help design suitable systems to overcome the energy crisis.