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• 2D g-C 3 N 4 nanosheet was fabricated by the supramolecular assembly approach. • Assembled 2D g-C 3 N 4 photocatalyst demonstrates enhanced HER performance. • 2D nanostructure accelerates charge transport and solar-to-hydrogen efficiency. • Ultrafast spectroscopy reveals charge carrier dynamics in 2D g-C 3 N 4 nanosheets. Two-dimensional graphitic carbon nitride (2D g-C 3 N 4) nanostructures have been the focus of substantial research interest recently owing to their promising photoactive properties for use in solar-to-fuel conversion. However, the synthesis of 2D g-C 3 N 4 nanomaterials remains a significant challenge. Here we successfully synthesized 2D g-C 3 N 4 nanosheets via a supramolecular chemistry approach. 2D g-C 3 N 4 nanostructures not only enhance the visible light-harvesting property but also provide more catalytic sites for improved hydrogen evolution reaction (HER). More importantly, we describe experimental findings concerning the dynamics of charge and energy transfer by using ultrafast spectroscopy in combination with in-situ electron spin resonance (ESR) characterization. The mechanistic investigation reveals that the introduction of a benzene-substituted melamine motif can remarkably accelerate the electron-hole separation and suppress the recombination of photogenerated charge carriers. The carrier separation dynamics is expected to be tailored by engineering the surface and morphology of g-C 3 N 4 , which favors enhanced solar photocatalytic HER efficiency. [ABSTRACT FROM AUTHOR]

Rational design and controllable synthesis of efficient electrocatalysts for water oxidation is of significant importance for the development of promising energy conversion systems, in particular integrated photoelectrochemical water splitting devices. Cobalt oxide (Co 3 O 4) nanostructures with mixed valences (II,III) have been regarded as promising electrocatalysts for the oxygen evolution reaction (OER). They are able to promote catalytic support of OER but with only modest activity. Here, we demonstrate that the OER performance of cubic Co 3 O 4 electrocatalyst is obviously improved when they are anchored on delaminated two-dimensional (2D) Ti 3 C 2 MXene nanosheets. Upon activation the overpotential of the hybrid catalyst delivers 300 mV at a current density of 10 mA cm−2 in basic solutions, which is remarkably lower than those of Ti 3 C 2 MXene and Co 3 O 4 nanocubes. The strong interfacial electrostatic interactions between two components contribute to the exceptional catalytic performance and stability. The enhanced OER activity and facile synthesis make these Co 3 O 4 nanocubes-decorated ultrathin 2D Ti 3 C 2 MXene nanosheets useful for constructing efficient and stable electrodes for high-performance electrochemical water splitting. [ABSTRACT FROM AUTHOR]

The donor-acceptor (D-A) interactions between the triazine ring unit and adjacent substituents is one of the decisive factors that affect the performance of triazine-based conjugated polymer photocatalysts. Herein, we design and synthesize novel conjugated polymers by introducing electron-drawing 1,3,4-oxadiazole units into 1,3,5-triazine-based π-conjugated skeletons for photocatalytic hydrogen production. Compared with the bulk polymer, the modified photocatalysts show extended visible light harvesting and boosted charge separation. Notably, under the irradiation of full-spectrum solar light, as-synthesized polymer with bi-1,3,4-oxadiazole linkage (denoted as TCP-BOXD) shows a highly improved hydrogen-evolving rate up to 3000 μmol g−1 h−1. Furthermore, DFT calculation reveals that N atoms in the introduced 1,3,4-oxadiazole unit, coupled with those in the triazine ring, act as synergistic bi-active sites for superior photocatalytic hydrogen production. Our findings may help the rational design and controllable synthesis of novel triazine-based conjugated polymers for photocatalysis. [Display omitted] • Novel triazine-based conjugated polymer photocatalysts were synthesized. • π-conjugated polymers show extended visible light harvesting and boosted charge separation. • The modified polymer shows a highly improved hydrogen-evolving rate up to 3000 μmol g−1 h−1. • DFT calculations reveal that N atoms in the introduced unit act as a synergistic active site. [ABSTRACT FROM AUTHOR]

Nitrogen-doped carbons (NC) and carbon nitride (C 3 N 4) belong to the two fundamental pillars of functionalized carbon materials that have broad applications in different fields. The synthesis of NC and C 3 N 4 often starts from different precursors, and a general approach that can offer both architectures is still highly sought. Herein, a facile Triton X-100-assisted copolymerization-carbonization strategy is reported to fulfill this task. By moderating the weight ratios of Triton X-100 and several conventional precursors of C 3 N 4 (e.g., dicyandiamide, urea, and cyanamide), a series of both types of N-functionalized carbons with controllable N dopants is successfully afforded. The yielded solids transform from graphitic C 3 N 4 with low surface areas to porous NC when the weight ratio reaches the critical values. This phenomenon might be attributed to the intensified copolymerization between the intermediates of both starting precursors during the carbonization, resulting in increased oxygen content and decreased N:C ratio in the products. Both the bulk and activated carbon-supported materials are then designed and used as metal-free catalysts in the dehydrochlorination of ethylene dichloride, a key reaction in polyvinyl chloride manufacture. It is found that NC is significantly more active than C 3 N 4 , but the corresponding supported catalysts exhibit an opposing trend. The structure-activity correlations suggest both the number of different N defects and the surface areas might play key roles in determining the dehydrochlorination chemistry. Tailor synthesis of C 3 N 4 and N-doped carbons with controllable N defects was enabled by a newly developed approach through co-pyrolysis of Triton X-100 and conventional C 3 N 4 precursors. [Display omitted] [ABSTRACT FROM AUTHOR]

• Modified g-C 3 N 4 nanostructures was fabricated by a preorganization approach. • g-C 3 N 4 photocatalysts demonstrate improved degradation and hydrogen production. • Nanostructure engineering accelerates charge carrier dynamics. • Tunable band structure and high-performance solar photocatalysis are achieved. Pristine graphitic carbon nitride (g-C 3 N 4) suffers from poor photocatalytic activity due to its limited light adsorption, small specific surface area and feasible recombination of photogenerated charge carriers. One practical approach to solve the problem of low solar-to-hydrogen efficiency is nanostructuring the morphology of g-C 3 N 4 to enhance its light-harvesting property and boost the rate of charge-carrier transportation. Here, we present a strategy to optimize the textural properties and catalytic performance of g-C 3 N 4 via using oxamide (OA) as a chemical modifier in the precursor solution, which significantly make the light absorption edge shift from 440 to 650 nm. Moreover, the nanostructure of the resultant g-C 3 N 4 can be easily tuned with increasing the amount of oxamide. The morphological features of g-C 3 N 4 materials change from sheet-like structure to tubular structure, porous nanotube and eventually interconnected porous sheet. More interestingly, the unique g-C 3 N 4 nanostructure offers advantages of a broader solar absorption spectrum and accelerates charge carrier dynamics that are favorable for advancing photocatalytic performance. The findings provide insightful information that can be used to understand the structure-property relationship in g-C 3 N 4 nanostructures for improved solar-to-fuel conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Double-modified g-C 3 N 4 -Cl-5H demonstrated highest benzaldehyde production (1.74 mg h−1) under sunlight. • Superoxide radical acted as the most critical active species via the inhibitor assays and product composition analysis. • Attachment sites of doped Cl on g-C 3 N 4 were calculated by comparing the density of states with the actual band gap. • Ammonium chloride provided Cl elements while acting as a porous-directing agent for the material. Lignin has become the largest renewable aromatic resource, and photocatalytic breaking of lignin linkage bonds has emerged as a promising green oxidation technology initiated by solar energy at room temperature. Wherein, carbon nitride (g-C 3 N 4) photo-cracking of lignin has the advantage of stability and reusability (no photo-corrosion), but is inefficient compared to conventional metal sulfides. In this work, g-C 3 N 4 was dual-modified with Cl doping and high-temperature oxidation, to maximum retain the π-π conjugation that can absorb the benzene ring structure in lignin. The inhibitor experiments and product composition analysis indicated that superoxide radicals acted as the most crucial active species, which was 4 times higher than that of g-C 3 N 4. The attachment sites of doped Cl on carbon nitride were calculated by comparing the density of states with the actual band gap. The as-fabricated g-C 3 N 4 -Cl-A5 photocatalyst showed a longer carrier lifetime and higher oxygen adsorption capacity and demonstrated excellent benzaldehyde production (1.74 mg h−1) from the lignin model under sunlight. The work provides insights into the enhanced superoxide radicals generation via photocatalysis and guidance for the selective breaking of lignin β-O-4 bonds. [ABSTRACT FROM AUTHOR]

5-Methylfurfural (MF) is a critical commodity chemical used as food additive and synthetic intermediate. Opening a sustainable route towards highly selective synthesis of MF from 5-hydroxymethylfurfural (HMF) is of great significance, but has demonstrated extremely challenging. Herein, we report an efficient process for the selective production of MF from HMF over an anatase-supported gold catalyst (Au/a-TiO 2). During the hydrogenolysis of HMF, the desired C O bond is maintained and MF can be obtained in a high yield of 83.1 %, exhibiting excellent stability both in batch and flow operation. A combination of experimental and theoretical analyses attribute the superior performance of Au/a-TiO 2 to the synergistic effect of limited H access, low adsorption of reactants, and avoiding condensation, driven by the high concentration of oxygen vacancies in the support. This study highlights a novel approach of tailoring the coverage of active species for the selective transformation of renewable compounds into high-value-added chemicals. [Display omitted] • Selective production of MF from HMF via direct hydrogenolysis of the hydroxyl group using the Au/a-TiO 2 catalyst. • The C=O functional group was preserved under reductive conditions and MF can be obtained in a high yield of 83.1%. • The Au/a-TiO 2 catalyst shows high activity, remarkable selectivity, and excellent stability both in batch and flow operation. • The synergistic effect of limited H access, low adsorption of reactants, high concentration of oxygen vacancies. • This study paves the way for the design of new bifunctional catalysts toward selective hydrogenolysis of biomass. [ABSTRACT FROM AUTHOR]

Photocatalytic lignin depolymerization emerges as a sustainable and cost-competitive strategy to produce low-molecular-weight aromatic chemicals from renewable resources. Significant efforts have been devoted to engineering C−C bond cleavage photocatalysts with diverse compositional and morphologic characteristics in the past decade. We herein present a facile photocatalytic strategy of promoting C−C bond cleavage in lignin models to achieve high-yield aromatic monomers over triazine-heptazine-based carbon nitride heterojunctions, exceeding the triazine- or heptazine-based counterparts. Mechanistic investigations reveal that the photo-excited electron and hole synergistically trigger the C−C bond cleavage. A combination of experimental results and theoretical calculations confirms that the improved photocatalytic performance is primarily attributed to the accelerated charge carriers separation and migration induced by the built-in electric field at the heterojunction interface, and the facilitated C β -radical generation. These findings highlight the effectiveness of interfacial engineering of intramolecular heterostructures towards the rational promotion of photocatalytic cleavage of C−C bond in lignin models. [Display omitted] • Carbon nitride heterojunctions are synthesized via NaCl/KCl-induced polymerization. • High selectivity of photocatalytic C−C bond cleavage in lignin models is achieved. • Excellent-yield for aromatic monomers is achieved over carbon nitride heterojunctions. • The photo-excited electron and hole synergistically trigger the C−C bond cleavage. • Carbon nitride heterojunctions accelerate electron-hole separation and migration. [ABSTRACT FROM AUTHOR]

[Display omitted] • A nearly total conversion and > 98% selectivity of C-C bond cleavage is achieved. • Sufficient superoxide radicals are necessary for highly selective C-C bond cleavage under visible light. • Efficient photocatalytic C-C bonds breaking towards lignin β -O-4 model compounds. • Ru single atoms outperform the nanoparticles for photocatalytic C-C bond cleavage. • C β -H extraction by photogenerated hole is the critical step of the transformation. The selective cleavage of the C C bonds in lignin is highly pursued to obtain aromatic monomers from renewable resources but remains challenging due to their high dissociation energies and steric hindrance between bulky aromatic groups. Herein, a mesoporous carbon nitride-supported ruthenium single-atom photocatalyst (Ru 1 /MCN) is reported for efficient oxidative C α -C β bonds scissoring towards lignin β -O-4 model compounds with high activity and selectivity under visible–light irradiation and room temperature. With this strategy, a nearly total conversion of > 99% and > 98% selectivity of C C bond cleavage can be achieved upon 2–phenoxy–1–phenylethanol. In-depth investigations verify that the C β -H extraction by photogenerated holes is the critical step of the transformation, which directly generates the C β radical intermediates and thus promotes the selective C α -C β bonds breaking by coupling with superoxide radicals induced by photogenerated electrons. This work explores the potential of single-atom catalysts for photocatalytic production of aromatics from renewable biomass feedstocks. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation is an eco-friendly technology for volatile organic compound (VOC) removal, but searching for a highly efficient photocatalyst system remains a challenge. Here, a novel photocatalyst, ZnO/Ti 3 C 2 T X composite, was developed by the electrostatic deposition strategy, wherein Ti 3 C 2 T X nanosheets serve as a support to provide abundant surface-active sites for loading ZnO spheres and adsorbing VOC molecules. Furthermore, successive catalytic centers are formed to enlarge the photocatalytic reaction interface, thereby minimizing the photogenerated electron transfer distances. Moreover, a Schottky heterojunction was successfully formed between the ZnO spheres and Ti 3 C 2 T X nanosheets, which further suppressed the recombination of photogenerated electron–hole pairs. As a result, the ZnO/Ti 3 C 2 T X composite exhibited enhanced photocatalytic activity, universality and stability in VOCs degradation. The photodegradation efficiencies of formaldehyde, methyl alcohol and acetone were as high as 91 %, 84 % and 80 % by ZnO/Ti 3 C 2 T X composite, respectively. The pseudo-first-order kinetic constant of formaldehyde decomposition on ZnO/Ti 3 C 2 T X was 2.69 times greater than that on pristine ZnO. This work presents a novel photocatalyst system of ZnO/Ti 3 C 2 T X composite and provides an insight for the development of highly efficient photocatalysts for the degradation of VOCs. [Display omitted] • ZnO/Ti 3 C 2 T X composite with Schottky heterojunction was successfully synthesized. • Successive catalytic centers minimized the photogenerated e− transfer distances. • Enhanced adsorption performance and photocatalytic activity were achieved. • ZnO/Ti 3 C 2 T X exhibited universality and stability in VOCs photodegradation. [ABSTRACT FROM AUTHOR]

Effectively harnessing renewable and inexhaustible solar radiation for energy conversion has attracted significant research interest in the past decade. Solar thermal conversion, as a ubiquitous phenomenon, can be implemented to evaporate water and concurrently boost photocatalytic performance for addressing freshwater scarcity and energy crisis. Most recently, solar water evaporation accompanied by photocatalytic degradation, sterilization, and hydrogen production has been proposed as a promising avenue to endow new vitality into the field of clean water and energy production. Driven by the advances of rationally designed solar-powered functional materials, a large variety of photothermal-coupled photocatalysis technologies have been exploited. In this context, it is imperative to summarize the recent progress and discuss the challenges in this multidisciplinary field. Herein, we overview photothermal materials based on various fundamental principles and highlight emerging applications in the areas of solar water evaporation, water purification, and solar-driven energy production. Furthermore, the challenges and perspectives toward both fundamental research and practical applications are also proposed. It is envisioned that this review can provide insightful suggestions to further advance the development of integrated solar thermal driven water evaporation and photocatalytic systems to fulfill concurrent energy conversion and environmental applications. [Display omitted] • The main design principles of concurrent photothermal and catalytic materials are summarized. • The photothermal energy boost physical and chemical reactions for improved water treatment. • The synergy of photothermal effect and photocatalysis can take full advantage of solar energy. • Sustainable water treatment with low-energy consumption shows great potentials in practical applications. [ABSTRACT FROM AUTHOR]

• A composite photocatalyst of Ag 3 PO 4 particles decorated on modified crispy g-C 3 N 4 flake was fabricated. • Photocatalytic oxygen evolution over Z-scheme heterojunction is roughly 7-fold higher than that in Ag 3 PO 4. • Highly efficient oxygen-evolving performance is mainly attributed to accelerated interfacial charge transfer. • Surface modification and nitrogen atmosphere favor well-organized g-C 3 N 4 nanostructures and enhanced photocatalytic activity. Searching for highly efficient photocatalysts for water oxidation is the footstone for the development of overall water splitting systems and has been actively pursued. The construction of artificial Z-scheme heterojunction photocatalysts has been conclusively proven to be effective in boosting charge transport property and in improving the OER performance. Herein, Ag 3 PO 4 particles anchored on modified crispy g-C 3 N 4 flakes have been successfully fabricated. KOH-assisted surface modification of g-C 3 N 4 flakes and intimate interfacial contact favor the accelerated charge transfer and highly improved OER efficiency. Ultrafast spectroscopy results reveal that modified g-C 3 N 4 with crispy nanostructures possesses more trap-induced long-lived photogenerated holes, which are extremely helpful to combine with photo-generated electrons from the conduction band (CB) position of Ag 3 PO 4 via the specific Z-scheme configuration, leaving more holes in the valence band (VB) of Ag 3 PO 4 for the enhanced OER. Superb oxygen-evolving performance highlight the great promise of Z-scheme Ag 3 PO 4 -based heterojunctions in solar-driven photocatalytic water splitting. [ABSTRACT FROM AUTHOR]

• 1D CdS/2D Ti3C2 MXene Schottky heterojunction was successfully fabricated. • In situ constructed Schottky photocatalyst exhibits enhanced HER performance. • Ultrathin 2D MXene enhances light absorption and accelerates charge transport. • The specific Schottky interface is responsible for the improved HER activity. Benefiting from excellent metallic conductivity, full-spectrum solar energy absorption and rich active sites on the surface, atomically thin two-dimensional transition metal carbide (2D MXene) shows great promise in improving solar-to-hydrogen efficiency and has drawn intense interest in the field of photocatalysis. However, controllable construction of ultrathin 2D MXene-based heterojunction photocatalysts still remains a significant challenge. Herein, one-dimensional (1D) CdS nanorod/2D MXene nanosheet heterojunctions with well-defined nanostructures and strong interfacial coupling are fabricated by in situ assembling solvothermally-generated CdS nanorods on ultrathin Ti 3 C 2 MXene nanosheets. Due to their specific interface characteristics, 1D/2D Schottky heterojunction is capable of providing accelerated charge separation and a lower Schottky barrier for solar-driven hydrogen evolution from water splitting. As expected, the Schottky-based photocatalyst is 7-fold more active in the illuminated hydrogen evolution reaction (HER) than pristine CdS nanorods, implying the synergistic effects between n-type semiconductor CdS and highly conductive 2D Ti 3 C 2 MXene nanosheets. [ABSTRACT FROM AUTHOR]

The first-line treatment of cerebral venous sinus thrombosis (CVST) is systemic anticoagulation. However, patients with severe or a clinically worsening condition might benefit from mechanical thrombectomy (MT) combined with intraoperative thrombolysis (IOT) or MT with continuous thrombolytic infusion (CTI). The present study compared the efficacy and safety of these 2 endovascular therapeutic methods by performing a systematic review of the literature. The present systematic review was conducted to identify all cases of CVST treated with MT+IOT or MT+CTI/MT+IOT+CTI reported in PubMed and Ovid. The recanalization rates, outcomes, operation-related complications, sequelae, and postoperative hemorrhage rates were evaluated. A total of 28 studies, including 82 patients, met the inclusion criteria. Alone, MT+IOT was performed in 42 patients (51%), and MT+CTI/MT+IOT+CTI was performed in 40 patients (49%). Overall, outcomes data were available for 69 patients, of whom 57 (82%) had had a good outcome and 12 (18%) had had a poor outcome or had died. Recanalization data were available for 68 patients. Of these patients, 28 (41%) had had complete recanalization, 40 (59%) had had partial, and no patient had had no recanalization. Operation-related complications occurred in 5 patients (6%), and 3 patients (4%) developed postoperative intracerebral hemorrhage. However, no significant differences were found in the recanalization rate or prognosis between the MT+IOT and MT+CTI/MT+IOT+CTI groups. The results from our review suggest that MT with local thrombolysis is relatively safe, with no significant differences in efficacy and safety between MT+IOT alone and MT+CTI/MT+IOT+CTI. However, randomized controlled studies are required to provide a definitive answer on its use for CVST. [ABSTRACT FROM AUTHOR]