Artificial photosynthesis that converts solar energy and CO₂ into value-added chemicals such as CO represents a highly promising route for sustainable energy production. However, the inherent limitations of graphitic carbon nitride (g-C₃N₄), including the lack of efficient active sites and sluggish charge transfer, significantly hinder its photocatalytic CO₂ reduction performance. Herein, a novel strategy is proposed in which amino-functionalized carbon dots (pCDs) mediate the construction of Co-N coordination active centers on g-C₃N₄ nanosheets (Co-5pCDs-g-C₃N₄). Advanced characterizations reveal that Co ions are anchored on the surface of the pCDs through Co-N coordination with amino groups, while the structural incorporation of the pCDs effectively reduces the lateral dimensions of the g-C₃N₄ nanosheets. This structural design markedly enhances charge-carrier separation within Co-5pCDs-g-C₃N₄, promotes charge migration toward the Co-N active centers, and enables highly selective CO₂ to CO conversion. Notably, Co-5pCDs-g-C₃N₄ achieves a remarkable CO production rate of 616.1 μmol·g^–1·h^–1, 91 times higher than Co-g-C₃N₄ with a CO selectivity of 92%. Femtosecond transient absorption (fs-TA) spectroscopy provides crucial mechanistic insights into the improved performance. The incorporation of pCDs significantly prolongs the average lifetime of photogenerated charge carriers, whereas the introduction of Co further extends this lifetime by promoting charge separation and suppressing recombination. Owing to the dual functions of pCDs in modulating charge dynamics and tailoring the coordination environment, the resulting catalyst demonstrates markedly enhanced photocatalytic CO₂ reduction performance, underscoring its strong potential for advanced solar-driven catalytic applications.

Porphyrins suffer from visible light excitation, which seriously restricts photothermal therapy (PTT) to superficial lesions. Developing porphyrin derivatives with near-infrared (NIR) absorption via chemical synthesis requires complicated synthesis and purification. In this work, the electron acceptor N,N'-di(L-alanine) perylene diimide (PDI) was introduced to the electron donor tetraminophenyl porphyrin (TAPP) to prepare the charge-transfer TAPP/PDI nanoparticles (NPs) as an NIR activatable photothermal agent via a simple and efficient nanoprecipitation method. When the molar ratio of TAPP to PDI was 1:2, uniformly dispersed TAPP/PDI NPs were obtained with a new NIR absorption peak (758 nm), along with fluorescence emission quenching. These results indicated that the charge transfer from the donor to the acceptor occurred within the TAPP/PDI NPs. The co-assembly forces were proven to originate from π−π interactions and hydrogen bond interactions, according to experiment results and molecular dynamic simulation. Furthermore, the energy gap of TAPP/PDI dimer was significantly narrowed, however, the spin-orbit coupling (SOC) constant was too small for intersystem crossing, which in favor of the NIR light activated non-radiative transition of TAPP/PDI NPs. Consistent with theoretical calculations, TAPP/PDI NPs could effectively generate heat with photothermal conversion efficiency (PCE) of 36.5% under the illumination of 808 nm laser. Antibacterial experiments demonstrated that TAPP/PDI NPs could induce the death of both Gram-positive S. aureus bacteria and Gram-negative E. coli bacteria, and could eradicate S. aureus infection in mice after only one treatment. Therefore, supramolecular co-assembly affords a facile approach for fabricating NIR activated porphyrin-based photothermal agents (PTAs) for photothermal therapy and beyond.

The orientation is the key factor to determine the physicochemical properties of the metal-organic framework (MOF) films. New strategies for oriented MOF films are of fundamental importance in the advancement of science and technology. Here we report a unified approach to the synthesis of a large variety of porphyrin-based MOF films with different directions, chemistries and properties. This strategy is based on a general electrochemical regulation of coordination process of different metal cation (M₁ = Zn, Co, Ni, Ce) and tetra (4-carboxyphenyl) porphyrin (M₂TCPP, M₂ = H, Cu, Pt, Pd) on various conductive substrates. The cathode strategy relies on the reduction of M₂TCPP ligands and follows the electrochemical reaction mechanism to achieve effective control over crystallizing M₁-M₂TCPP MOF films oriented in the (110) direction. The highly oriented M₁-M₂TCPP MOF films are endowed with excellent crystalline, spatial network structure and hierarchical three-dimensional pore structure, which is conducive to charge transfer and material transmission and suitable for use as an electrochemical catalyst. The Zn-TCPP MOF films on conductive substrate could be used directly as an electrochemical sensor for electrocatalytic oxidation of NaNO₂, and showed wide linear range, low limit of detection (0.24 μM), high sensitivity (285.8 mA/(mM·cm²)) and good anti-interference performance. We believe our methodology provides a simple and convenient route to a variety of oriented porphyrin-based MOF films for nanodevices with novel structure and function in nanotechnology.

The development of atmospheric pressure N₂ reduction to NH₃ is attracting much attention in green chemistry, yet it is still a challenge to obtain satisfactory activity under mild conditions. Herein, an efficient near-infrared (NIR) photothermal catalysis reduction of N₂ constitutes an occurrence is reported. With or without V-substitute polyoxometalates (POMs) loaded on the surface of Fe-chelated polydopamine (Fe-PDA) photothermal support through the electrostatic interactions, NIR photothermal catalysts POMs@Fe-PDA are fabricated. The induction of “FeV” cofactor facilitates electron transfer between V(V)/V(IV)&Fe(III)/Fe(II) and N₂, thereby activating N₂ molecule. The synergy between the catalytic activity of V-POMs and the local NIR photothermal effect of Fe-PDA dramatically enhances N₂ reduction. Noticeably, PMo₁₀V₂@Fe-PDA exhibits a significantly enhanced NH₃ production rate of 181.1 μmol·L⁻¹ with a turnover frequency of 1006.1 mmol·M⁻¹·h⁻¹ under 808 nm NIR laser radiation, being the highest values reported at atmospheric pressure. We expect that this work could provide an alternative approach for photothermal catalysis N₂ reduction under mild conditions.

The combination of donor–acceptor (D–A) structures presents a viable strategy for fabricating covalent organic frameworks (COFs) with exceptional photocatalytic performances. Nevertheless, the selection of functional groups on donor or acceptor building blocks and their effect on the macroscopic properties of COFs are ambiguous. In this study, we tactfully synthesized a pair of Py-DBT-COFs from the same pyrene (Py) donor and 4,7-diphenylbenzo[c][1,2,5]thiadiazole (DBT) acceptor cores with distinct primitive functional groups. The primitive functional groups of building units determine the photocatalytic properties of corresponding Py-DBT-COFs. Specifically, Py-C-DBT-COF synthesized from Py-4CHO and DBT-2NH₂ showcases a splendid H₂ evolution rate as high as 21,377.7 μmol/(g·h) (with 5 wt.% Pt) originating from better charge transfer capacity, which is significantly superior to that of Py-N-DBT-COF constructed from Py-4NH₂ and DBT-2CHO. The distinct photocatalytic performances of the two COFs are demonstrated to originate from the different charge separation and transfer capabilities. This work supplies a new avenue for optimizing the photocatalytic performance of D–A COFs from the perspective of primitive functional group selections.

The continuous and sustainable photo-activity on micro- or nano-carriers has always been a key stepping stone in the industrialization of photo-catalysis, photo-synthesis, and photo-degradation. Herein, we report a new series of positively charged hollow microspheres carrying porphyrin moieties. Such hollow spheres are formed through crosslinking of well-ordered porous thin laminates, initiated by co-assembly of regular monomers and those decorated with porphyrin moieties. On the surface of an individual sphere, densely distributed positive sites attract anionic reactants. The superficial porphyrin decomposes the accumulated reactants under 1 Sun. After degradation and release of products, the photoactive sites are thereby renewed. We demonstrate that polymer network (1:10) exhibited superior sustainable photocatalytic performance with complete degradation of methyl orange (MO) in 40 min with no observable performance deterioration after six cycles. The established close loop of adsorption–reaction–release cycle makes possible many efficient and continuous photo-catalytic processes.

Chemodynamic therapy (CDT) offers a promising alternative to conventional cancer treatment. However, the limited acidity and H₂O₂ concentration in tumor microenvironment (TME) severely impair the anticancer effects of CDT. In this study, we report a microemulsion-assisted coassembly method to prepare iron(III) tetraphenylporphyrin (FeTPP) and magnetic (Fe₃O₄) nanocomposite material (FeTPP@Fe₃O₄), using photoactive FeTPP and Fe₃O₄ nanocrystals as building blocks. The self-assembling nature of FeTPP results in disordered aggregation and fluorescence quenching, leading to a high light-to-heat conversion efficiency. Continuously, the photo-thermal effect enhances the catalytic decomposition of hydrogen peroxide (H₂O₂) in the Fenton reaction on Fe₃O₄ nanocrystals to generate highly toxic hydroxyl radicals (·OH) to destroy cancer cells. This cascade reaction produces a synergistic therapeutic effect between CDT and photothermal therapy (PTT), which significantly amplifies the therapeutic effect and enhances the treatment outcome of cancer patients. The highly efficient tumor catalytic therapy in vivo results confirmed that this nanomedicine treatment is an excellent biocompatible catalytic nanomedicine therapy achieved through a photo-enhanced Fenton reaction activity approach.

Molecular self-assembly is a natured-inspired strategy to integrate individual functional molecules into supramolecular nanostructured materials through noncovalent bond interactions for solar to fuel conversion. However, the design and engineering of the morphology, size, and orderly stacking of supramolecular nanostructures remain a great challenge. In this study, regular porphyrin nanocrystals with different orderly stacked structures are synthesized through noncovalent self-assembly of Pt(II) meso-tetra (4-carboxyphenyl) porphine (PtTCPP), using surfactants with different electronegativity. The synergy of noncovalent bond interactions between porphyrin molecules, and between porphyrin molecules and surfactants resulted in different molecular packing patterns. Due to the spatial ordering of PtTCPP molecules, the different nanocrystals exhibit both collective optical properties and morphology-dependent activities in photocatalytic hydrogen production. The measurements of the photodeposition of dual cocatalysts showed that the photogenerated electrons and holes selectively aggregated at different active sites, revealing separation pathways and directional transfer of photogenerated electrons and holes in the assemblies. This study provides a new strategy to exert rational control over porphyrin self-assembly nanocrystals for highly efficient water splitting.

The use of functional nanoparticles as peroxidase-like (POD-like) catalyst has recently become a focus of research in cancer therapy. Phthalocyanine is a macrocyclic conjugated metal ligand, which is expected to achieve a high POD-like catalytic activity, generating free radicals and inhibiting the proliferation of cancer cells. In this paper, we synthesized phthalocyanine nanocrystals with different structures through noncovalent self-assembly confined within micro-emulsion droplets, and manganese phthalocyanine (MnPc) possessing a metal–N–C active center was used as the building block. These nano-assemblies exhibit shape-dependent POD-like catalytic activities, because the emulsifier and MnPc co-mixed assembly reduced the close packing between MnPc molecules and exposed more active sites. The assembly had a water-dispersed nanostructure, which is conducive to accumulation at tumor sites through the enhanced permeability and retention effect (EPR). Because of a highly efficient microenvironmental response, the assembly showed higher catalytic activity only emerged under the acidic tumor-like microenvironment, but caused less damage to normal tissues in biomedical applications. In vivo and in vitro catalytic therapy tests showed excellent anti-tumor effects. This work explored a new way for the application of metal–organic macromolecules such as MnPc as nanozymes for catalytic tumor therapy.

Nanoparticle photosensitizers possess technical advantages for photocatalytic reactions due to enhanced light harvesting and efficient charge transport. Here we report synthesis of semiconductor nanoparticles through covalent coupling and assembly of metalloporphyrin with condensed carbon nitride. The resultant nanoparticles consist of light harvesting component from the condensed carbon nitride and photocatalytic sites from the metalloporphyrins. This synergetic particle system effectively initiates efficient charge separation and transport and exhibits excellent photocatalytic activity for CO₂ reduction. The CO production rate can reach up to 57 μmol/(g·h) with a selectivity of 79% over competing H₂ evolution. Controlled experiments demonstrate that the combination of light harvesting with photocatalytic activity via covalent assembly is crucial for the high photocatalytic activity. Due to effective charge separation and transfer, the resultant nanoparticle photocatalysts show exceptional photo stability against photo-corrosion under light irradiation, enabling for long-term utilization. This research opens a new way for the development of stable, effective nanoparticle photocatalysts using naturally abundant porphyrin pigments.