Simultaneous Photocatalytic Production of H and Acetal from Ethanol with Quantum Efficiency over 73% by Protonated Poly(heptazine imide) under Visible Light.

In this work, protonated poly(heptazine imide) (H-PHI) was obtained by adding acid to the suspension of potassium PHI (K-PHI) in ethanol. It was established that the obtained H-PHI demonstrates very high photocatalytic activity in the reaction of hydrogen formation from ethanol in the presence of Pt nanoparticles under visible light irradiation in comparison with K-PHI. This enhancement can be attributed to improved efficiency of photogenerated charge transfer to the photocatalyst's surface, where redox processes occur.

Vinyl-Group-Anchored Covalent Organic Framework for Promoting the Photocatalytic Generation of Hydrogen Peroxide.

The artificial photosynthesis of HO from water and oxygen using semiconductor photocatalysts is attracting increasing levels of attention owing to its green, environmentally friendly, and energy-saving characteristics. Although covalent organic frameworks (COFs) are promising materials for promoting photocatalytic HO production owing to their structural and functional diversity, they typically suffer from low charge-generation and -transfer efficiencies as well as rapid charge recombination, which restricts their use as catalysts for photocatalytic HO production. Herein, we report a strategy for anchoring vinyl moieties to a COF skeleton to facilitate charge separation and migration, thereby promoting photocatalytic HO generation.

S-scheme heterojunction of crystalline carbon nitride nanosheets and ultrafine WO nanoparticles for photocatalytic CO reduction.

Highly crystalline carbon nitride polymers have shown great opportunities in overall water photosplitting; however, their mission in light-driven CO conversion remains to be explored. In this work, crystalline carbon nitride (CCN) nanosheets of poly triazine imide (PTI) embedded with melon domains are fabricated by KCl/LiCl-mediated polycondensation of dicyandiamide, the surface of which is subsequently deposited with ultrafine WO nanoparticles to construct the CCN/WO heterostructure with a S-scheme interface. Systematic characterizations have been conducted to reveal the compositions and structures of the S-scheme CCN/WO hybrid, featuring strengthened optical capture, enhanced CO adsorption and activation, attractive textural properties, as well as spatial separation and directed movement of light-triggered charge carriers.

Hydroxyl-Bonded Ru on Metallic TiN Surface Catalyzing CO Reduction with HO by Infrared Light.

Synchronized conversion of CO and HO into hydrocarbons and oxygen via infrared-ignited photocatalysis remains a challenge. Herein, the hydroxyl-coordinated single-site Ru is anchored precisely on the metallic TiN surface by a NaBH/NaOH reforming method to construct an infrared-responsive HO-Ru/TiN photocatalyst. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (ac-HAADF-STEM) and X-ray absorption spectroscopy (XAS) confirm the atomic distribution of the Ru species.

Bottom-up Synthesis of Single-Crystalline Poly (Triazine Imide) Nanosheets for Photocatalytic Overall Water Splitting.

Poly (triazine imide) (PTI/Li Cl ), one of the crystalline versions of polymeric carbon nitrides, holds great promise for photocatalytic overall water splitting. In principle, the photocatalytic activity of PTI/Li Cl is closely related to the morphology, which could be reasonably tailored by the modulation of the polycondensation process. Herein, we demonstrate that the hexagonal prisms of PTI/Li Cl could be converted to hexagonal nanosheets by adjusting the binary eutectic salts from LiCl/KCl or NaCl/LiCl to ternary LiCl/KCl/NaCl.

Rh/Cr O and CoO Cocatalysts for Efficient Photocatalytic Water Splitting by Poly (Triazine Imide) Crystals.

In situ photo-deposition of both Pt and CoO cocatalysts on the facets of poly (triazine imide) (PTI) crystals has been developed for photocatalytic overall water splitting. However, the undesired backward reaction (i.e.

Electronic Transmission Channels Promoting Charge Separation of Conjugated Polymers for Photocatalytic CO Reduction with Controllable Selectivity.

Conjugated polymers (CPs) represent a promising platform for photocatalytic CO fixation owing to their suitable band structures that meet the requirements of the reduction potential of CO to value-added fuels. However, the photocatalytic performance of CPs is rather restrained by the low charge transfer efficiency. Herein, we rationally designed three CPs with a more delocalized electronic transmission channel and planar molecular structure, which are regarded to evidently reduce the exciton binding energy (E ) and accelerate the internal charge transfer process.

Salt-Melt Synthesis of Poly Heptazine Imides with Enhanced Optical Absorption for Photocatalytic Hydrogen Production.

Broadening the visible light absorption range and accelerating the separation and migration process of charge carriers are effective ways to improve photocatalytic quantum efficiencies. In this study, we show that poly heptazine imides with enhanced optical absorption and promoted charge carrier separation and migration could be obtained by means of a rational design of the band structures and crystallinity of polymeric carbon nitride. Copolymerization of urea with monomers such as 2-aminothiophene-3-carbonitrile would first generate amorphous melon with enhanced optical absorption, while further ionothermal treatment of melon in eutectic salts would increase the polymerization degree and create condensed poly heptazine imides as final products.

The Directional Crystallization Process of Poly (triazine imide) Single Crystals in Molten Salts.

Poly (triazine imide) photocatalysts prepared via molten salt methods emerge as promising polymer semiconductors with one-step excitation capacity of overall water splitting. Unveiling the molecular conjugation, nucleation, and crystallization processes of PTI crystals is crucial for their controllable structure design. Herein, microscopy characterization was conducted at the PTI crystallization front from meso to nano scales.

Surface Coating of Amorphous TiO Enables Efficient Vapor-fed Photocatalytic Overall Water Splitting with Substantial Apparent Quantum Yield.

Photocatalytic overall water splitting represents a promising strategy for sustainable hydrogen production. However, photocorrosion and dissolution of photocatalysts and cocatalysts are common concern for the solid-liquid phase reaction. Recently, the above issues could be addressed by Domen and coworkers, when the photocatalytic water splitting was conducted in the presence of water vapor, which dramatically restrain the undesired corrosion of the photocatalysts and cocatalysts.

Heptazine-Based Ordered-Distorted Copolymers with Enhanced Visible-Light Absorption for Photocatalytic Hydrogen Production.

Poly(heptazine imide) (PHI), one of the attractive allotropes of polymeric carbon nitride, has recently received extensive attention in photocatalysis due to its extended conjugation for fast separation and transfer of the charges. However, pristine PHI bears an intrinsic optical absorption band edge at 460 nm, which largely restrains the visible light utilization. Herein, the narrow-bandgap PHI (N-PHI) with an ordered-distorted interface was fabricated from polycondensation of the mixture of NaSCN, cyanuric chloride, and LiCl.

Improved Charge Separation in Poly(heptazine-triazine) Imides with Semi-coherent Interfaces for Photocatalytic Hydrogen Evolution.

The construction of heterojunctions is a promising manner to accelerate the separation and transfer of the charge carriers at the interface. Herein, a binary poly(heptazine-triazine) imides (PHI/PTI) with semi-coherent interfaces was fabricated via a facile two-step salt-melt synthetic process. The built-in electric fields at the semi-coherent interface endow prompt exciton splitting and charge carrier separation.

Surface Engineering of Conjugated Polybenzothiadiazoles and Integration with Cobalt Oxides for Photocatalytic Water Oxidation.

Conjugated polymers feature promising structure and properties for photocatalytic water splitting. Herein, a hydrolysis strategy was demonstrated to rationally modulate the surface hydrophilicity and band structures of conjugated poly-benzothiadiazoles. High hydrophilicity not only enhances the dispersions of polymeric solids in an aqueous solution but also reduces the absorption energy of water molecules.

Molecular Design of Covalent Triazine Frameworks with Anisotropic Charge Migration for Photocatalytic Hydrogen Production.

Covalent triazine frameworks (CTFs) represent promising polymeric photocatalysts for photocatalytic hydrogen production with visible light. However, the separation and transfer of charges in CTFs are isotropic because of the uniform distribution of donor-acceptor motifs in the skeleton. Herein, to achieve the anisotropic charge carrier separation and migration, thiophene (Th) or benzothiadiazole (BT) unit is selected as the dopant to modify the molecular structure of CTF-based photocatalysts.

Ionothermal Synthesis of Covalent Triazine Frameworks in a NaCl-KCl-ZnCl Eutectic Salt for the Hydrogen Evolution Reaction.

Covalent triazine-based frameworks (CTFs) are typically produced by the salt-melt polycondensation of aromatic nitriles in the presence of ZnCl . In this reaction, molten ZnCl salt acts as both a solvent and Lewis acid catalyst. However, when cyclotrimerization takes place at temperatures above 300 °C, undesired carbonization occurs.

CrowdMed-II: a blockchain-based framework for efficient consent management in health data sharing.

The healthcare industry faces serious problems with health data. Firstly, health data is fragmented and its quality needs to be improved. Data fragmentation means that it is difficult to integrate the patient data stored by multiple health service providers.

Fully Condensed Poly (Triazine Imide) Crystals: Extended π-Conjugation and Structural Defects for Overall Water Splitting.

Conventional polymerization for the synthesis of carbon nitride usually generates amorphous heptazine-based melon with an abundance of undesired structural defects, which function as charge carrier recombination centers to decrease the photocatalytic efficiency. Herein, a fully condensed poly (triazine imide) crystal with extended π-conjugation and deficient structure defects was obtained by conducting the polycondensation in a mild molten salt of LiCl/NaCl. The melting point of the binary LiCl/NaCl system is around 550 °C, which substantially restrain the depolymerization of triazine units and extend the π-conjugation.

Automatic approach for constructing a knowledge graph of knee osteoarthritis in Chinese.

In this study, a medical knowledge graph is constructed from the electronic medical record text of knee osteoarthritis patients to support intelligent medical applications such as knowledge retrieval and decision support, and to promote the sharing of medical resources. After constructing the domain ontology of knee osteoarthritis and manually labeling, we trained a machine learning model to automatically perform entity recognition and entity relation extraction, and then used a graph database to construct the knowledge graph of knee osteoarthritis. The experiment proves that the knowledge graph is comprehensive and reliable, and the knowledge graph construction method proposed in this study is effective.

Visible-Light Flow Reactor Packed with Porous Carbon Nitride for Aerobic Substrate Oxidations.

A triphasic photocatalytic reactor employing a mesoporous carbon nitride photocatalyst and aerobic O was assembled to operate under continuous flow conditions. This reactor design allows for facile downstream processing and reusability in multiple flow cycles. The selective aerobic oxidation of alcohols and amines was chosen to demonstrate the applicability and performance advantage of this flow approach compared to that of conventional batch photochemistry.

Molecular Junctions on Polymeric Carbon Nitrides with Enhanced Photocatalytic Performance.

Molecular catalysts (MC), namely homogeneous catalysts, have demonstrated great promise for efficient solar-to-chemical energy conversion in the hybrid system. However, the poor interfacial interaction between MC and photosensitizers (PS) impedes the efficient and fast interfacial electron transfer. To promote interfacial communication between PS and MC, a proof-of-concept method was developed for the combination of polymeric carbon nitride (PCN) PS with bipyridine cobalt [Co(bpy) ] MC by covalent bonds, creating molecular junctions to promote interfacial electron transfer as confirmed by transient photoluminescence lifetime and electrochemical measurements.

Oxysulfide Semiconductors for Photocatalytic Overall Water Splitting with Visible Light.

Photocatalytic overall water splitting by sulfide-based materials is a great challenge because of the poor resilience of such materials against hole oxidation. In a recent study, Domen and co-workers developed an innovative strategy to stabilize sulfide-based photocatalysts by hybridizing S 3p with O 2p orbitals to produce oxysulfides in which S is stable. Further surface engineering of the oxysulfides with dual co-catalysts promoted charge separation and interface transfer, thus reducing the charge build-up that inhibits photocorrosion.

Electron Deficient Monomers that Optimize Nucleation and Enhance the Photocatalytic Redox Activity of Carbon Nitrides.

Polymeric carbon nitride (PCN) is usually synthesized from nitrogen-rich monomers such as cyanamide, melamine, and urea, but is rather disordered in many cases. Now, a new allotrope of carbon nitride with internal heterostructures was obtained by co-condensation of very electron poor monomers (for example, 5-amino-tetrazole and nucleobases) in the presence of mild molten salts (for example, NaCl/KCl) to mediate the polymerization kinetics and thus modulate the local structure, charge carrier properties, and most importantly the HOMO and LUMO levels. Results reveal that the as-prepared NaK-PHI-A material shows excellent photo-redox activities because of a nanometric hetero-structure which enhances visible light absorption and promotes charge separation in the different domains.

Reducing the Exciton Binding Energy of Donor-Acceptor-Based Conjugated Polymers to Promote Charge-Induced Reactions.

Exciton binding energy has been regarded as a crucial parameter for mediating charge separation in polymeric photocatalysts. Minimizing the exciton binding energy of the polymers can increase the yield of charge-carrier generation and thus improve the photocatalytic activities, but the realization of this approach remains a great challenge. Herein, a series of linear donor-acceptor conjugated polymers has been developed to minimize the exciton binding energy by modulating the charge-transfer pathway.