Self-assembly of biomimetic light-harvesting complexes capable of hydrogen evolution

Abstract

Biomimetics provides us a new perspective to understand complex biological process and strategy to fabricate functional materials. However, a great challenge still remains to design and fabricate biomimetic materials using a facile but effective method. Here, we develop a biomimetic light harvesting architecture based on one-step co-assembly of amphiphilic amino acid and porphyrin. Amphiphilic amino acid can self-assemble into nanofibers via π-stacking and hydrogen binding interactions. Negatively charged porphyrin adsorbs on the surface of the assembled nanofibers through electrostatic force, and the nanofibers further organize into porous urchin-like microspheres induced presumably by hydrophobic interaction. The assembled amphiphilic amino acid nanofibers work as a template to tune the organization of porphyrin with an architecture principle analogous to natural light harvesting complex. The co-assembled microspheres exhibit enhanced light capture due to the light reflection in the porous structure. Reaction center (platinum nanoparticles) can be effectively coupled with the light harvesting microspheres via photoreduction. After visible light illumination, hydrogen evolution occurs on the hybrid microspheres.