Efficient and sustained photosynthetic hydrogen production by algae under high light intensity

Cleaner, lower carbon energy is needed for more sustainable development. Algal production of hydrogen directly from water and sunlight is a promising route toward such sustainable energy. However, algae can only produce hydrogen continuously in weak light. We developed a hybrid system using a designed thermosensitive material, poly(N-isopropylacrylamide)-co-poly(butyl acrylate) (PNIPAM-BA), and a photothermal material, graphene oxide (GO), to dynamically sense light intensity. This system regulates the entry of incident light to protect the activity of algal hydrogenase, which enables algae to efficiently produce hydrogen through photosynthesis across a range of light intensities (100-2000 μmol photons·m^-2·s^-1). Even under the standard maximum solar intensity of 2000 μmol photons·m^-2·s^-1, we achieved continuous hydrogen production over 25 days with an average hydrogen production rate of 17.53 μmol H₂ (mg chlorophyll)^-1 h^-1. Thus, this study addresses the challenge of continuous hydrogen production by algae under high light intensity, greatly advancing prospects for large-scale outdoor hydrogen production.