Erwin Reisner

Carbon dots (CDs) have emerged as scalable, metal-free photocatalysts, but their use as conjugate organo-photocatalysts for enantioselective chemistry remains unexplored. Here, we covalently anchor a chiral imidazolidinone organocatalyst to amorphous, citric acid-derived CDs, giving a colloidal conjugate that acts as both photosensitizer and enantiodetermining component. This chiral CD material promotes the asymmetric radical α-alkylation of aldehydes in up to 84% yield and 93% e.e. Its semihomogeneous nature enables catalyst recovery by precipitation and reuse over five cycles with only minor loss in yield and e.e. The well-dispersed conjugate is also compatible with continuous photoflow, where Bayesian optimization in only 10 experiments enabled a gram-scale reaction in 80% yield and 91% e.e. This work establishes chiral conjugate CDs as a practical, recoverable platform for sustainable asymmetric photocatalysis.

Linker isomerism represents a powerful, yet unexploited, strategy for programming framework topology and unlocking chemical complexity in high-connectivity reticular systems. Here, we demonstrate the reticular synthesis of two 12-connected nanographene-based zirconium metal–organic frameworks, MOF-1300 and MOF-1400, wherein network architecture is directed by the meta versus para carboxylate substitution patterns of a 12-connected linker, dodeca-carboxylate hexakis[3,5-bis(m/p-carboxyphenyl)-4,6-dimethoxyphenyl]hexabenzocoronene (m/p-HBC-LH12). The meta isomer directs the assembly of an 8-connected cubic Zr cluster to yield MOF-1300 with an unprecedented trinodal (3,6,8)-c rcb1 net, representing a new topology in reticular chemistry. Conversely, the para isomer enforces 12-connectivity at the Zr cluster with hexagonal prismatic geometry to yield MOF-1400 with a rare trinodal (3,6,12)-c kex net which has not previously been observed in Zr-MOFs. Beyond structure, both frameworks serve as solid reservoirs of photoactive nanographenes: under basic photoredox conditions, they release their molecular HBC linkers, which act as homogeneous organophotoredox catalysts for the hydrodefluorination of polyfluoroarenes under simulated solar light (AM 1.5G). This behavior highlights the potential of reticular materials as precatalysts for the delivery of molecular photocatalysts and provides a basis for exploring such materials in future photocatalytic applications.

Photosynthesis compartmentalizes reactions across the thylakoid membrane in vivo to upcycle CO ₂ into complex chemicals that are fundamental to life. Herein, we demonstrate a step toward achieving a synthetic equivalent to the chloroplast with a compartmentalized cascade reaction in vitro that enables light driven CO ₂ utilization for organic synthesis in one‐pot. This bioinspired compartmentalization enables the photocatalytic reduction of aqueous CO ₂ by water‐soluble catalysts and dyes to produce CO, which then moves into the more buoyant organic layer and is consumed in aminocarbonylation or carbonylative variants of Sonogashira and Suzuki couplings, including the synthesis of the pharmaceutical itopride. The reaction compartmentalization significantly increases the biomimicry of CO ₂ utilization by enabling the light‐driven generation and utilization of CO from CO ₂ for chemical synthesis in the same pot compared to previous two‐pot approaches. The fundamental platform and design criteria described herein can enable future reactions to utilize building blocks as abundant as CO ₂ to generate complex molecules through bioinspired pathways.

Photosynthesis compartmentalizes reactions across the thylakoid membrane in vivo to upcycle CO ₂ into complex chemicals that are fundamental to life. Herein, we demonstrate a step toward achieving a synthetic equivalent to the chloroplast with a compartmentalized cascade reaction in vitro that enables light driven CO ₂ utilization for organic synthesis in one‐pot. This bioinspired compartmentalization enables the photocatalytic reduction of aqueous CO ₂ by water‐soluble catalysts and dyes to produce CO, which then moves into the more buoyant organic layer and is consumed in aminocarbonylation or carbonylative variants of Sonogashira and Suzuki couplings, including the synthesis of the pharmaceutical itopride. The reaction compartmentalization significantly increases the biomimicry of CO ₂ utilization by enabling the light‐driven generation and utilization of CO from CO ₂ for chemical synthesis in the same pot compared to previous two‐pot approaches. The fundamental platform and design criteria described herein can enable future reactions to utilize building blocks as abundant as CO ₂ to generate complex molecules through bioinspired pathways.

Direct air capture (DAC) coupled to photocatalytic CO ₂ splitting offers a route to simultaneously mitigate atmospheric CO ₂ accumulation and produce sustainable fuels. However, integrations of DAC with photocatalytic CO ₂ conversion have thus far relied on ultraviolet-light-absorbing TiO ₂ and organic substrate oxidation, limiting solar energy utilisation and precluding a truly artificial photosynthetic reaction. Here, we introduce an integrated direct air carbon capture and utilisation (DACCU) system that couples under continuous flow nighttime atmospheric CO ₂ capture with daytime gas-phase photocatalytic CO ₂ splitting to CO and O ₂ using a solid silica−amine adsorbent and a γ-Al ₂ O ₃ -supported visible-light-absorbing Z-scheme photocatalyst system, respectively. Gas-phase operation benefits CO ₂ delivery and suppresses H2 evolution, achieving ~88% CO selectivity and ~100 h stability. Isotopic labelling confirmed that CO and O ₂ originates from CO ₂ and water, respectively. The DACCU prototype was operated outdoors over two consecutive day–night cycles, enabling continuous DAC at night with solar-thermal desorption and solar-driven conversion in the day. This work represents the first demonstration of producing solar fuels from only atmospheric CO ₂ and moisture at low temperature and pressure and therefore provides a critical advance for the practical deployment of photocatalytic CO ₂ splitting technologies.

Lignin is a large-scale, renewable carbon source that remains underutilized due to its complex polymeric structure. Photocatalytic conversion of lignin promises selective bond cleavage to yield functionalized products but is hindered by its strong light absorption. Herein, we report a biphasic photocatalytic system that avoids light competition and enables the generation of both CO and functionalized aromatics from Kraft lignin under visible light at ambient temperature and pressure. This system uses water-dispersed CdS quantum dots to photocatalyze the conversion of Kraft lignin’s aldehyde and hydroxyl groups to CO via a decarbonylation mechanism. The biphasic system enables this biomass-derived CO to be used in situ for aminocarbonylation. Concurrent cleavage of the β-O-4 bonds in Kraft lignin releases functionalized aromatic products with 81% yield. This work demonstrates the simultaneous light-driven production of sustainable aromatics and one-pot utilization of lignin for carbonylation of organics via cascade reactions.

A bifunctional Pd catalyst was developed for simultaneous H ₂ evolution and waste polyethylene terephthalate reforming. The practical deployment of the system was demonstrated with an outdoor 1 m ² prototype.

Photocatalytic reforming offers a route to valorize biomass and plastic waste into clean H ₂ under ambient conditions. However, the scalability of photocatalyst sheets is limited by high-temperature processing, binders and complex co-catalyst deposition. Here a [Co ₄ Zr ₂ O(O ⁿ Pr) ₁₀ (acac) ₄ ] single-source precursor is deposited onto Al-doped SrTiO ₃ and immobilized on glass substrates to fabricate photocatalyst sheets using multiple techniques, including high-throughput spray coating. The resulting sheets enable photoreforming of cellulose- and polyethylene terephthalate-derived feedstocks, producing H ₂ alongside value-added organics such as formate, acetate, glycolate and glycolaldehyde dimer. The system is demonstrated from the centimeter- to meter-squared scale, culminating in a 1-m ² outdoor reactor operating under natural sunlight. After 6 h, H ₂ yields reached 5.24 and 1.51 mmol m ⁻² for glucose and pretreated cellulose, respectively, with concurrent formation of oxygenates. Techno-economic analysis based on real-world data estimates an H ₂ cost of £0.93 mmol ⁻¹ . This work advances scalable photocatalytic reforming and provides a step towards practical deployment.