A semiartificial photosynthesis approach that utilizes enzymes for solar fuel production relies on efficient photosensitizers that should match the enzyme activity and enable long-term stability. Polymer dots (Pdots) are biocompatible photosensitizers that are stable at pH 7 and have a readily modifiable surface morphology. Therefore, Pdots can be considered potential photosensitizers to drive such enzyme-based systems for solar fuel formation. This work introduces and unveils in detail the interaction within the biohybrid assembly composed of binary Pdots and the HydA1 [FeFe]-hydrogenase from Chlamydomonas reinhardtii. The direct attachment of hydrogenase on the surface of toroid-shaped Pdots was confirmed by agarose gel electrophoresis, cryogenic transmission electron microscopy (Cryo-TEM), and cryogenic electron tomography (Cryo-ET). Ultrafast transient spectroscopic techniques were used to characterize photoinduced excitation and dissociation into charges within Pdots. The study reveals that implementation of a donor−acceptor architecture for heterojunction Pdots leads to efficient subpicosecond charge separation and thus enhances hydrogen evolution (88 460 μmol H2 •g H2ase −1•h −1 ). Adsorption of [FeFe]-hydrogenase onto Pdots resulted in a stable biohybrid assembly, where hydrogen production persisted for days, reaching a TON of 37 500 ± 1290 in the presence of a redox mediator. This work represents an example of a homogeneous biohybrid system combining polymer nanoparticles and an enzyme. Detailed spectroscopic studies provide a mechanistic understanding of light harvesting, charge separation, and transport studied, which is essential for building semiartificial photosynthetic systems with efficiencies beyond natural and artificial systems.

Organic semiconductor−microbial photosynthetic biohybrid systems show great potential in light-driven biosynthesis. In such a system, an organic semiconductor is used to harvest solar energy and generate electrons, which can be further transported to microorganisms with a wide range of metabolic pathways for final biosynthesis. However, the lack of direct electron transport proteins in existing microorganisms hinders the hybrid system of photosynthesis. In this work, we have designed a photosynthetic biohybrid system based on transmembrane electron transport that can effectively deliver the electrons from organic semiconductor across the cell wall to the microbe. Biocompatible organic semiconductor polymer dots (Pdots) are used as photosensitizers to construct a ternary synergistic biochemical factory in collaboration with Ralstonia eutropha H16 (RH16) and electron shuttle neutral red (NR). Photogenerated electrons from Pdots promote the proportion of nicotinamide adenine dinucleotide phosphate (NADPH) through NR, driving the Calvin cycle of RH16 to convert CO 2 into poly-3-hydroxybutyrate (PHB), with a yield of 21.3 ± 3.78 mg/L, almost 3 times higher than that of original RH16. This work provides a concept of an integrated photoactive biological factory based on organic semiconductor polymer dots/ bacteria for valuable chemical production only using solar energy as the energy input.

A phenoxazine-based small organic donor POZ-M is designed and synthesized to prepare organic heterojunction nanoparticles (NPs) with a small acceptor ITIC for photocatalytic hydrogen production, giving a reaction rate up...

Metal nanoparticles have been widely exploited in catalysis, but their full impact on the environment and human health is still under debate. Here we describe the one-step fabrication of polymer microbead-supported metal and metal oxide nanoparticles and their application as recoverable nanocatalysts for reactions under batch and flow conditions. Au, Ag and Fe₃O₄ nanoparticles were prepared directly at the surface of benzylamine-coated spherical polymer beads in water by using low energy microwave radiation. The morphology and size of the nanoparticles, and therefore their catalytic properties, were tuned by modifying the bead surface using betalamic acid, an antioxidant from plant origin. The catalytic performance and recovery of these environmentally friendly nanocatalysts was demonstrated towards model redox chemical transformations. We anticipate the results reported herein can provide important insights into the controlled and facile synthesis of microparticle supported nanocatalysts under mild conditions.

(NH4)2[Co(H2O)6]2 [V10O28]·4H2O (I) and (NH4)2 [Co(H2O)5(β‐HAla)]2 [V10O28]·4H2O (II) are used for the preparation of mixed oxides as catalysts for water oxidation.