Molybdenum sulfides with bismuth halide perovskites for better photocatalysis

Clean hydrogen from photocatalysis

Hydrogen is regarded as a promising energy carrier for the future world. Solar-driven photocatalysis provides a cleaner and more sustainable approach for hydrogen production, which would not produce any carbon footprint theoretically. This reaction of hydrogen production needs photocatalysts (mainly semiconductors). To make full use of solar irradiation, photocatalysts are desirable to capture visible light and even near infrared light, which accounts for 95% of the solar spectrum. However, most of photocatalysts can only absorb UV light (5%) and thus significantly limit their photocatalytic activity.

Bismuth halide perovskites as new photocatalysts

Bismuth halide perovskites have gained new interest in photocatalysis due to the better stability and reduced toxicity compared to their lead-based analogues. They can utilize the whole solar spectrum after precise bandgap tunability and show good photocatalytic activities, including hydrogen production. However, their activity is still inferior to the lead-based counterparts and there is much room to improve their activity.

Molybdenum sulfides as co-catalysts for better activity

It’s proved that Pt or its composites are the most active co-catalysts for hydrogen production, while its application raises concerns due to their high cost and low abundance. Molybdenum sulfides is recognized as one of the most promising alternatives of noble Pt. Here we find that molybdenum sulfides are efficient co-catalysts of bismuth halide perovskites and can significantly enhance the photocatalytic activity for hydrogen evolution. Together with our cooperators, we have found the underlying mechanism behind the enhancement of photocatalytic activity and the positive role of molybdenum sulfides. This research contributes to the rational design of halide perovskite photocatalysts for hydrogen generation. It’s pleasure to note that clean hydrogen and the associated hydrogen economy have been implemented in Finnish academic society recently while they need more attention in Finnish communities to improve the competence in the field of green energy and sustainable future.

He Zhao received a 12,000 euro part-year grant from the Finnish Foundation for Technology Promotion in the spring of 2023. He is a doctoral researcher at University of Oulu in the Environmental Engineering doctoral program.