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Heterogeneous photo-Fenton catalysts prepared by doping metal ions in g-C3N4 are promising alternatives to traditional homogeneous Fenton catalysts, but are restricted by poor mesoporous structure and agglomerate of metal species. Recently, the highly uniformly dispersed metal-N active sites in various photocatalysts have been proved to be the critical reason for their enhanced catalytic activity. In this study based on reasonable control of mesoporous structure and metal-N active sites, mesoporous Fe-g-C3N4 was synthesized using a simple one-step thermal shrinkage polymerization method using ferrous oxalate as iron source and pore-forming agent. The Fe and N elements in the triazine ring skeleton of Fe-g-C3N4 form a σ-π bond, thus the photogenerated electrons can be quickly transferred to Fe3+ to form Fe2+ under the interaction of chemical bonds, accelerating the Fenton reaction rate. Density functional theory calculations results demonstrate that the energy band structure and electron cloud density distribution of Fe-Nx active structure are better than that of routine FeOx crystal structure with metal species agglomeration. In addition, the excellent mesoporous structure of Fe-g-C3N4 creates conditions for the high exposure of Fe-Nx active sites in the photo-Fenton reaction under visible light. The as-developed Fe-g-C3N4 system shows high recyclability and excellent photo-Fenton performance for removal of typical intractable pollutants (The degradation rate of dye and tetracycline reaches 98.2% and 98.7% at 60 and 120 min, respectively). This work provides a facile and sustainable route to develop mesoporous highly-active heterogeneous Fenton-like catalysts and even further general the design of general catalyst with ideal metal-N active sites, thereby promoting a feasible and efficient wastewater remediation solution.

A highly-efficient Fe–g-C3N4 photo-Fenton catalyst was prepared using ferrate as a critical iron source and defect control additive. The complementary synergistic effects of Fe species and defect sites promote photoelectron transfer.

Potassium iodate (KIO3), an edible salt additive, was used as a critical waste-free modifier in the thermal polymerization of g-C3N4, leading to the harmonious K–I–O co-modification of g-C3N4 for a boosted charge separation and photocatalytic performance.

Lightweight 3D porous self-floating platforms with enriched light-water-air-material interactive interfaces are promising candidates to promote solar energy utilization, regarding the requirements of solar-inspired reactions such as photothermal spill oil recovery and photocatalytic hydrogen production. Herein, we report a facile and controllable method to prepare lightweight porous carbon sponges by using low-cost melamine-formaldehyde (MF) foams as an environmental-friendly template and raw material, which are a widely-used mass disposal building solid waste with high porosity. Scanning electron microscopy shows the natural 100 μm level porous network structure of the MF foams is retained after carbonization. Nitrogen adsorption-desorption isotherms and corresponding pore size distributions clearly indicate the carbon sponges have unique hierarchical mesoporous features, which are beneficial for remediation of spilt oil or composite photocatalysis. X-ray diffraction data and Raman spectra verify the partial graphitization of the mesoporous carbon sponges, and Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy confirm the presence of N- and O-containing functional groups. Joule-heating performance testing in a simulated oil spill case under sunlight shows that the carbon sponges are superior over the supported graphene containing a positive control in terms of heating and rheological regulation effects, and thus are useful in oil spill recovery. Further photocatalytic hydrogen evolution experiments using the graphitic carbon nitride (g-C3N4) semiconductor-coated carbon sponge suggest the successful assembly of an efficient carbon/g-C3N4 H2 production platform. Hence, this low-cost waste MF foam-derived carbon sponge platform with high mechanical applicability and durability is promising for use in various energy and environmental applications.

Defective functional-group-endowed polymer semiconductors, which have unique photoelectric properties and rapid carrier separation properties, are an emerging type of high-performance photocatalyst for various energy and environmental applications. However, traditional oxidation etching chemical methods struggle to introduce defects or produce special functional group structures gently and controllably, which limits the implementation and application of the defective functional group modification strategy. Here, with the surface carboxyl modification of graphitic carbon nitride (g-C

Hierarchical porous carbons (HPCs) with optimized porosity and enriched surface functional groups are a promising carbon material for supercapacitor development. However, it is a challenge to reali...

Nicotinamide mononucleotide (NMN) is an essential precursor of nicotinamide adenine dinucleotide (NAD+), which is an essential coenzyme for various physiological processes including energy metabolism, DNA repair, and cell growth. NMN promotes tumor growth since it may fuel cancer cells via enhancement of NAD+ and plays a role in the prevention of liver and pancreatic cancers in mice. In the current study, the role of NMN in oncogenesis of lung cancer was investigated. To investigate whether NMN can prevent lung cancer formation, C57 mice were intraperitoneally injected with NMN daily for two weeks followed by subcutaneous injection of mouse lung cancer cells (LLC). Three weeks later, the tumor incidence and tumor size and volume were measured. To verify whether NMN can inhibit tumor growth, a xenograft model was constructed in nude mice. After intraperitoneal injection with NMN for three weeks, the mice's weight and tumor volume were measured. Then tumor slides were stained with hematoxylin–eosin (H&E) and immunostaining of Ki-67. Carcinoembryonic antigen (CEA) and tumor-associated inflammatory factors IL-1β, IL-6, TNF-α, and CXCL-12 were detected using enzyme-linked immunosorbent assay. After NMN treatment, the tumor formation rates in the two C57 mouse groups were both 100%. The tumor volume has no statistical difference between the NaCl control group and NMN treatment group. Immunohistochemical study of Ki67 in tumor sections from the two groups indicated that NMN does not affect the proliferation of tumor cells. The tumor volume in nude mice has no statistical difference either between the NaCl control group and NMN treatment group. NMN does not affect the proliferation of tumor cells in mouse subcutaneous tumors. However, it was found that the mice's weight was significantly reduced in the NMN treatment group. Carcinoembryonic antigens (CEA), interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and stromal cell-derived factor 1 (CXCL-12) have no significant difference between the two groups. Our findings indicate that NMN does not prevent formation of lung cancer or restrain tumor growth in a mouse xenograft model, nor does it promote tumor growth. It was found that NMN can significantly reduce the weight of the nude mice.

With the merits of high energy density and environmental friendliness, the lithium–sulfur battery (LSB) has been perceived as a next-era energy storage device. However, issues such as the insulating nature of sulfur, polysulfide shuttling, huge volume change, and tardy polysulfide intermediate conversion cause rapid capacity decay, severe self-discharging, and drastic drop in coulombic efficiency, and impede the commercialization of LSBs. Many working steps of LSBs suffer from the problem of “dead sulfur”, which can no longer be cycled for various reasons. How to suppress “dead sulfur” and improve the reaction kinetics has been a major research interest in recent years. Among numerous studies that aim to solve these problems, the search for more efficient catalytic materials that facilitate polysulfide intermediate conversion and chemically anchor soluble lithium polysulfides has drawn increasing attention. This review focuses on the design and mechanistic interpretation of various advanced catalytic materials for the activation of “dead sulfur” in LSBs.

Potassium-ion batteries (KIBs) are gradually being considered as an alternative for lithium-ion batteries because of their non-negligible advantages such as abundance and low expenditure of K, as well as higher electrochemical potential than another alternative─sodium-ion batteries. Nevertheless, when the electrode materials are inserted and extracted with large-sized K+ ions, the tremendous volume change will cause the collapse of the microstructures of electrodes and make the charging/discharging process irreversible, thus disapproving their extended application. In response to this, we put forward a feasible strategy to realize the in situ assembly of layered MoSe2 nanosheets onto N, P codoped hollow carbon nanospheres (MoSe2/NP-HCNSs) through thermal annealing and heteroatom doping strategies, and the resulting nanoengineered material can function well as an anode for KIBs. This cleverly designed nanostructure of MoSe2/NP-HCNS can broaden the interlayer spacing of MoSe2 to boost the efficiency of the insertion/extraction of K ions and also can accommodate large volume change-caused mechanical strain, facilitate electrolyte penetration, and prevent the aggregation of MoSe2 nanosheets. This synthetic method generates abundant defects to increase the amounts of active sites, as well as conductivity. The hierarchical nanostructure can effectively increase the proportion of pseudo-capacitance and promote interfacial electronic transfer and K+ diffusion, thus imparting great electrochemical performance. The MoSe2/NP-HCNS anode exhibits a high reversible capacity of 239.9 mA h g-1 at 0.1 A g-1 after 200 cycles and an ultralong cycling life of 161.1 mA h g-1 at 1 A g-1 for a long period of 1000 cycles. This nanoengineering method opens up new insights into the development of promising anode materials for KIBs.

Potassium-ion batteries (KIBs) are gradually being considered as an alternative for lithium-ion batteries because of their non-negligible advantages such as abundance and low expenditure of K, as well as higher electrochemical potential than another alternative─sodium-ion batteries. Nevertheless, when the electrode materials are inserted and extracted with large-sized K

Powerful yet orderly nanostructure lithium-ion batteries (LIBs) are eagerly desired to satisfy the practical application of portable electronics and smart grids. However, the surface re-stacking and surface functionalization on the MXenes in the anode electrode severely restrict the accessibility to electrolyte ions, hindering the full utilization of their intrinsic properties. To address this challenge, we rationally design three-dimensional (3D) Sn@Ti3C2 materials and fabricate them in a unique layer-by-layer manner through self-assembly for boosting LIBs. In this design system for fast lithium-ion storage, the Ti3C2 MXene nanosheets serving as 3D scaffolds buffer the severe volume expansion and agglomeration of Sn nanoparticles (NPs) and enhance electrode conductivity at the interface. Furthermore, Sn NPs are embedded as interlayer spacers to prevent nanosheet re-stacking and provide outstanding electrochemical performance. The nanostructure can increase the lithium-ion diffusion coefficient and create additional active sites. As a result, the Sn@Ti3C2 anode exhibits a superior specific capacity up to 666 mA∙h∙g−1 at 0.5 A∙g−1 after 250 cycles. Compared with pure Sn NPs, the improved electrochemical performance of Sn@Ti3C2 can be ascribed to the high electronic conductivity of Ti3C2 MXene nanosheets. The 3D Sn@Ti3C2 materials prepared in a layer-by-layer manner through self-assembly display promising performances for LIBs.

High reactive oxygen species (ROS) generation efficiency and induction of targeted cell apoptosis are recognized as key objectives to achieve a highly efficient strategy for cancer therapy with minimum side effects of inflammatory reactions. However, it is still a challenge to realize higher therapeutic efficiency with a cell apoptosis model. Herein, we present strong upconversion luminescent biosafe cores derived from Linde Type A (LTA) zeolites and modification with targeted/therapeutic drugs for multimodal therapy, in which sonodynamic therapy (SDT) combined with photodynamic therapy (PDT) increases therapeutic efficiency especially in deep sites of tumor via producing cytoplasmic ROS and mitochondrial superoxide and photothermal therapy (PTT) enhances PDT effects via higher fluorescence resonance energy transfer (FRET) efficacy attributed to an increased temperature. Furthermore, the transcriptomic analysis reveals that cellular internalization of the nanosystem can lead to tumor ablation via cell apoptosis. We expect that the multimodal therapy based on LTA zeolite drug nanocarriers could be applied in the cancer therapeutics in the near future.

CdS@BN NRs core-shell photocatalysts for hydrogen evolution were synthesized by a solvothermal and chemical adsorption method. CdS NRs coated by 5 wt% boron nitride (BN) shell exhibited remarkably visible-light photocatalytic hydrogen evolution activity of up to 30.68 mmol g−1 h−1, nearly 6.79 times higher than that of pure CdS NRs, and the apparent quantum efficiency at 420 nm was 7.5%. Transmission electron microscopy showed the CdS NRs were coated with a thin (~5 nm) BN layer, which together with the hydrogen evolution results proved the photocatalytic ability of CdS NRs was significantly improved. The hydrogen evolution rate of CdS NRs coated by 5 wt% BN remained at 91.4% after four cycles, indicating the photocorrosion of CdS NRs was effectively alleviated. Moreover, the large and close coaxial interfacial contact between the CdS core and the BN shell was beneficial to the separation and transfer of photogenerated electron-hole pairs.

The co-modulation of the oxygen-containing and amino groups in the polymeric semiconductor graphitic carbon nitride (g-CN) has increasingly become a common concern toward advanced catalysis, energy and biomedicine applications. The intensive understanding of the existence state of oxygen-containing and amino groups in the polymeric structure of g-CN and the controllable methods of modulating these groups is highly desirable. Herein, a rational industrially applicable plasma strategy was designed and applied for controllable modulation of oxygen-containing and amino groups in g-CN within 10 min. X-ray diffractometry, Fourier transform infrared spectrometry, and X-ray photoelectron spectroscopy results indicated that the oxygen-containing and amino groups were controllably introduced after plasma treatment. Transmission electron microscopy, atomic force microscopy and N2 adsorption-desorption measurements verified the ultra-thin and two-dimensional in-plane mesoporous morphology of the optimized g-CN-O-NH2. As a result, the rational g–CN–O-NH2 performed well in Cr(VI) photoreduction, photocatalytic bacterial disinfection and inactivation of tumor cells. The remarkable extensively applicable photocatalytic activity can be ascribed to the fast charge carrier transfer benefiting from the enriched preferable internal edge sites and ideal joint effect of internal –NH2 and OH- groups, as confirmed by the significantly weakened PL fluorescence intensity and prolonged fluorescence lifetime of the excited states under visible light irradiation. This work provides an impressive industrially applicable strategy for the structure optimization and functional groups modulation of polymeric materials towards enhanced electronic and catalytic performances.

Iron silicide is widely used in the steel and metallurgical industry, and it shows anti-corrosion performance in acidic solution. In this paper, we report an FeSi2–air battery in an acidic saline electrolyte for the first time. The usage of the FeSi2 anode in acidic electrolyte can overcome the limitations of the Fe anode in alkaline electrolyte, such as the formation of a passive layer on the surface of the anode, low solubility of Fe(OH)2, etc. In this paper, we are the first to assemble an FeSi2–air battery in acidic saline electrolyte, which showed a high specific capacity of 1.90 A h g−1 in 0.5 M H2SO4 saline electrolyte in the presence of F− ions, which was close to approximately 80% of the theoretical capacity. Control experiments were carried out to propose possible mechanisms of the discharge of the FeSi2 anode in acidic saline electrolyte. In the presence of F− ion in acidic saline electrolyte, a sustainable discharge process can last for a long period until the active material in the anode is used up. Furthermore, it shows an excellent utilization of both gravimetric capacity and volumetric capacity compared with other metal, metalloid and metal/metalloid–air batteries. Considering the less pollution of the environment, the FeSi2–air battery will be a competitive battery with high specific capacity and utilization for further applications.

The environmentally-harmful by-product – biomass tar – is the major obstacle during biomass gasification, which produces synthetic gas as a clean energy source from agricultural waste or other bio-wastes. The highly-dispersed Fe/Ni-based nano-catalysts are of great research interest because of their great catalytic performance for catalytic biomass tar cracking. Supported Fe/Ni alloy catalysts were recognized as promising tar-cracking catalysts with the ability of redox enhancement and carbon deposition prevention. However, the controllable synthesis of highly-dispersed Fe/Ni nano-catalysts with high activity and stability remains a huge challenge. In this work, highly-dispersed FeNi alloy catalysts embedded in graphitic carbon (BC-FeNi) were successfully synthesized by simple calcination of a bacterial precursor, which can be easily harvested by collecting non-pathogenic bacteria in a Fe/Ni ion enriched liquid medium. The bacteria served as a carbon source and helped to uniformly distribute the iron–nickel ions in the precursor for subsequent preparation of highly-dispersed FeNi catalysts. Transmission electron microscopy showed the BC-FeNi contained well-dispersed iron-nickel nanoparticles with sizes of 3–10 nm in a mesoporous graphitic carbon matrix, which were beneficial for the protection of metal nanoparticles against coking and thus were highly desirable for catalytic biomass tar cracking. The conversion rate of the biomass tar model compound – toluene by BC-FeNi nano-catalysts was 82.6% at 700 °C and 95.8% at 800 °C, which were significantly superior over the control sample supported by active carbon. Noticeably, the metal loading (1.01 wt%) in the bacteria-derived BC-FeNi catalysts was very lower compared to previous studies using other synthetic methods (usually >10 wt%). This unique nature grants that the bacterial method may enable the facile design and synthesis of other types of practical nano-materials.

CoSe2 is considered as a promising candidate among non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) due to its intrinsic metallicity and low Gibbs free energy for hydrogen adsorption. Recently, the hexagonal CoSe2 becoming increasingly popular owing to its chemically favorable basal plane, which provides more active sites, but remains limited by the poor stability. In this study, we design a small-molecule-amine-assisted hydrothermal method to in situ anchor the hexagonal CoSe2 nanosheets (NSs) on nitrogen-doped reduced graphene oxides (RGO) as an advanced electrode material for HER. Due to the existence of abundant functional groups and high specific surface area of RGO, the hexagonal CoSe2 NSs could be stably formed on RGO. As a result, only a small overpotential of 172 mV is needed for the optimized sample to drive a current density of 10 mA cm−2 in 0.5 M H2SO4 and the Tafel slope is 35.2 mV dec−1, which is comparable with the state-of-the-art Pt catalyst (32.3 mV dec−1). Therefore, the facile and low-cost method for synthesizing hexagonal TMDs with robust electrical and chemical coupling developed in this work is promising in promoting the large-scale application of non-precious electrocatalysts.

A 3D flower-like mesoporous Ce doped ZnO composite composed of nanosheets was prepared by a facile, one-step wet chemical method at room temperature. It was found that the moderate Ce doping can improve the light absorption of ZnO. The photocatalytic activities of the samples were studied by the degradation of Rhodamine B (RhB) and phenol under stimulated sunlight. The 1% mole ratio of Ce doped ZnO composites (denoted as CZ1) showed higher photocatalytic performance than other samples, where 85.1% of RhB and 69.6% of phenol can be removed within 125 min and 120 min, respectively. The Ce4+ doped in the lattice of ZnO can act as the electron trapping sites, which effectively improve the electron-hole separation. In addition, it was also found the annealing temperature had effect on the morphology and structure of Ce doped ZnO. The photocatalytic performance can be further enhanced at proper annealing temperature (500 °C) due to the increase of ZnO crystallinity with maintained flower-like structure and the formation of CeO2-ZnO heterojunction at their tight interface promoting the separation of photogenerated electron-hole pairs.

Structural defects and surface functional groups defects engineering in the graphitic carbon nitride (g-C3N4) polymer semiconductor usually has great benefit in optimizing its electron structure and photocatalytic performance. In this study, one type of carboxyl group defects-grafting g-C3N4 was prepared through glucose oxidase treatment on the initial O sites in the g-C3N4, which played multi-functional roles in the generation of carboxyl groups and melon structure defect. FT-IR, XPS and 13C NMR analysis verified the presence of highly favorable carboxyl groups, which was beneficial to the fast separation and migration of photogenerated carriers. The singularity of enzyme mediated defects control of carbon nitride materials was greatly boosted on O-enriched g-C3N4 (OCN) further supporting the overall O sites ring-opening hypothesis. The glucose oxidase (GOD) treated reconstructed g-C3N4 photocatalysts showed narrowed band gaps and fast charge separation ability as verified by UV–vis DRS and electrochemical tests. As a result, the optimized photocatalyst (GOD-OCN-3d) showed a high Cr(VI) photocatalytic detoxification rate of 99 %, which was 6.6 times higher than that of raw g-C3N4 (15 %) in 120 min. These findings open the understanding on precise molecular defects modulation of g-C3N4 via an environmental-friendly enzyme treatment approach, as well as providing a new avenue for understanding the function of structural defects of photocatalysts on prompting charge separation.

Heterogeneous photo-Fenton catalysts prepared by doping metal ions in g-C

Inspite of their impressive high theoretical capacity as Lithium-ion batteries (LIBs) anodes, spinel transition-metal oxides (TMOs) suffer serious volume expansion, aggregation and the pulverization of crystal structures during lithiation/delithiation, and this process severely restrict their industrial application. Multi-dimensional morphological engineering of spinel TMO nanostructures is an effective way to solve this issue. In this work, using facile hydrothermal synthetic methods, spinel CuCo2O4 nanowires arrays are synthesized and supported on g-C3N4 nanosheets, thus forming a unique sandwich-like interconnected three-dimensional mesoporous structure containing high amount of void spaces. Addition of g-C3N4 nanosheets to CuCo2O4 nanowire arrays may shorten the Li+ diffusion distance and electron transfer pathway, and may also provide more active sites for Li+ diffusion into electrolyte and buffer for the volume expansion and aggregation of CuCo2O4. As a LIB anode material, CuCo2O4@g-C3N4 shows initial lithiation capacity of 840.6 mAh g−1, and capacity retention of 641.2 mAh g−1 after 60 cycles at the current density of 0.1 A g−1 and 499.2 mAh g−1 after 40 cycles at high current of 1 A g−1, which is significantly better than value of pure CuCo2O4 nanowires. This work affords a new way to tackle the problem of volume expansion of high capacity spinel TMO anode materials using g-C3N4 nanosheets as buffering agent.

Over the past decade, there has been significant research of Co3O4 catalysts for oxidation of carbon mono-oxide (CO) at low temperatures. However, development of water-resistant Co3O4 materials is still challenging. In this work, a novel oxygen vacancy-rich nitrogen-doped Co3O4 catalyst was developed using straightforward urea-assisted method. Nitrogen doping increases oxygen vacancies on the surface in Co3O4 as well as improves the activity of lattice oxygen. Comparing with pure Co3O4 and Co3O4 with less nitrogen doping, the as-synthesized nitrogen-doped Co3O4 exhibited significantly enhanced activity as well as water resistance in the catalytic oxidation of CO. To the best of our knowledge, this is the first example of CO oxidation on N-doped Co3O4, which provides a new strategy for developing highly active and water-resistant catalysts.

Chemisorption of CO2 by amine-based solid adsorbents is an effective approach to reduce the greenhouse effect. However, the scalable fabrication of excellent materials with superior CO2 adsorption capacity and outstanding cycle performance remains a big challenge. Here we demonstrate a unique architecture of macroscopic 3D porous graphene-like carbon nanosheets (3D-PGCNs) through a simple one-step carbonization of a mixture of melamine and natural soybean oil. The key feature of 3D-PGCNs is that the formed ultrathin graphene-like carbon nanosheets have crumpled morphology and 3D interconnected macropore structure, leading to a high pore volume (3.48 cm3 g−1) with capable of loading large amount of amine species. As a result, the 3D hybrid (3D-PEI-PGCNs) impregnated with 40 wt% polyethyleneimine (PEI) exhibits a high CO2 adsorption capacity of 117 mg g−1 at 75 °C with excellent cycling stability. This work provides a new strategy for the simple, cost-effective and scalable synthesis of efficient and stable CO2 capture sorbents.

Novel Pd/TiO2 nanotube arrays (Pd/TNTAs) were fabricated by introducing Pd nanoparticles onto TNTAs via a facile deposition–reduction method. Pd nanoparticles can uniformly distribute over the inner and outer surfaces of TiO2 nanotubes by controlling the Pd loading. The hybrid prepared by two deposition–reduction cycles (Pd/TNTAs-2) showed the best visible light absorption and the highest transient photocurrent density compared with the pure TNTAs and other Pd/TNTAs. The Pd/TNTAs-2 sample also showed the best photocatalytic activity and recyclability toward the degradation of Rhodamine B (RhB). As much as 99.7% of RhB could be removed over the Pd/TNTAs-2 film within 2 h under visible light irradiation, which is about three times higher than that over P25 films. The enhancement is attributed to the surface plasmon resonance of Pd nanoparticles and the effective interaction between Pd nanoparticles and TiO2 nanotubes, which improves the charge transfer and reduces the recombination rate of the photogenerated electron–hole pairs.

MSnO4 (M = Mn, Zn, Co, Mg, etc.) has been widely investigated as an anode material for lithium-ion batteries in recent years, but its practical applications are limited by serious capacity loss caused by severe volume expansion during Li+ insertion/extraction. So far, hollow structures, carbon coating, and encapsulation by reduced graphene oxide have been introduced to improve the electrochemical properties of MSnO4. In this study, Mn2SnO4 nanoparticles@reduced graphene oxide (Mn2SnO4@rGO) composites were prepared using simple steps and applied as anode materials for lithium-ion batteries. The rGO sheet encapsulated Mn2SnO4 nanoparticles show improved electrochemical properties. The first discharge capacity of Mn2SnO4@rGO reaches 1223.5 mAh g-1 and remains at 542.0 mAh g-1 after 100 cycles at a current density of 0.1 A g-1. The electrochemical properties were significantly improved compared to those of pure Mn2SnO4 nanoparticles.

Porous graphitic carbon nitride (g-C3N4) was successfully synthesized by a simple bacterial etching method. Compared with bulk g-C3N4, the specific surface area of the porous g-C3N4 increased from 14.48 to 75.22 m2/g, and its photocatalytic activity was significantly enhanced by a factor of 2.49 for photocatalytic H2 evolution. The enhancement of photocatalytic activity is attributed to the enlarged specific surface area, remarkably narrowed band gap (2.28 eV) and fast electron transportation benefit from the porous structure.

As a promising visible-light-responsive catalyst, graphitic carbon nitride (g-C 3 N 4 ) has been widely used in environmental and energy applications owing to its unique semiconducting optoelectronic properties. However, the photocatalytic performance of bulk g-C 3 N 4 synthesized using N-containing precursors via a conventional thermal polycondensation process is generally limited by low crystallinity caused by incomplete polymerization. In addition to forced polymerization under high-pressure conditions, removing the unpolymerized and inactive part of bulk g-C 3 N 4 through controllable etching is another practical way to optimize its crystallinity. Therefore, we developed an economical and general method to fabricate g-C 3 N 4 with high crystallinity and excellent photocatalytic properties, in which cheap sodium nitrite aqueous solution is utilized as a moderate etching agent. The compositions and physiochemical properties of the products were comprehensively investigated by X-ray diffraction, Fourier-transform infrared spectroscopy, ultraviolet visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, N 2 adsorption-desorption, and electrochemical impedance spectroscopy measurements. In addition, ToF-SIMS (time-of-flight secondary ion mass spectrometry), a new surface analysis technology, was also used to determine the surface and structural characteristics of all samples. The obtained g-C 3 N 4 shows ideal high-crystallinity features and excellent charge transfer ability, leading to significantly improved Cr(vi) reduction activity under visible light. Moreover, there is only a low content of nitrite residue (63.3 mg g -1 ) in the final g-C 3 N 4 product, indicating that the method employing NaNO 2 , which is widely used in the food industry, is safe and waste-free. Therefore, the new controllable NaNO 2 etching method is cleaner and more efficient than commonly-used corrosion approaches based on strong acids or strong oxidants, and thus affords a new strategy in the regulation and structural design of various catalysts.

Hydrogen generation photocatalyzed by low-cost graphite carbon nitride (g-C3N4) is a fascinating and effective route to solve energy crisis, but is mainly limited by the few reactive sites, low carrier separation efficiency and mediocre visible-light utilization. In this work, these limitations were tackled through a facile eco-friendly precursor pretreatment by tuning bulk g-C3N4 into porous structure. This pretreatment restricted agglomeration in the subsequent condensation and created more porous channels for charge carrier transfer and more surface active sites for reaction. The modified g-C3N4 has larger surface area, broader visible-light response, enhanced electron migration capacity and prolonged lifetime of photogenerated carriers. These well-amended g-C3N4 nanosheets possess an average hydrogen evolution rate 5.7 times that of bulk g-C3N4. This work affords a facile, eco-friendly and scalable strategy to design or synthesize other porous materials.

3D porous nanosheets composite comprised of graphitic carbon nitride (g-C3N4) and carbon was prepared by a simple pyrolysis and subsequent carbothermal activation method for the first time. The morphology and structural properties of obtained 3D porous g-C3N4/C nanosheets composite was systematically investigated. It was found that the morphology of the g-C3N4/C composite evolved from scroll-like structure to 3D porous nanosheets with ultrathin layer after 6 h activation, meanwhile, the specific surface area and pore volume were significantly increased. Such 3D porous nanosheets like these can function as effective catalysts for a range of gas-phase photocatalytic reactions such as photocatalytic reduction of CO2 with H2O vapor to produce value-added fuels. As a demonstration, outstanding photocatalytic activity was achieved on this 3D porous g-C3N4/C nanosheets composite, where ultra-high CO and CH4 yield of 229 and 112 μmol g−1-cat, respectively, were acquired under 7 h simulated solar irradiation, which were 25-fold better than that of bulk g-C3N4. The excellent photocatalytic performance should be attributed to the advantageous structural and compositional features.

Reactive oxygen species (ROS) production efficiency, tumor microenvironment hypoxia relief, and autophagy-induced cell death with minimal negative effects are considered the main objectives to achieve more efficient tumor treatment. However, realizing highly effective cancer treatment under hypoxia relief with a cell autophagy model based on suitable biomaterials is still a challenge. Herein, a biosafe upconversion nanomaterial based on Linde Type A (LTA) zeolites loaded with carbon nitride (C3N4) photocatalyst and chlorin e6 (Ce6) was developed as a rationally regulated photocatalytic system and multimodal tumor therapeutic platform. C3N4 contributes to stability, tumor hypoxia relief, high surface conductivity and high drug-loading. Remarkably, photodynamic therapy (PDT) and sonodynamic therapy (SDT) were proven capable of maximizing the ROS yield to obtain highly tumor therapeutic outcomes. Photothermal conversion efficiency was 46.72%. Furthermore, internalized nanomaterials can result in tumor inhibition through cell autophagy. The as-developed system shows a promising potential in the multimodal cancer therapeutics.

Aiming at developing a moderate and efficient sono-photodynamic therapy for breast cancer, tissue engineering scaffolds may provide an easy and efficient strategy to eliminate serious side effects in conventional surgery or chemotherapy, and thus, they are highly desired. However, the development of ideal sono-photodynamic therapeutic scaffolds is always hindered by the poor stability and incompatibility between the different biomaterial components. Herein, the Food and Drug Administration (FDA)-approved sono/photosensitizer Chlorin e6 (Ce6) was successfully and tightly incorporated into electrospun polycaprolactone/gelatin (PG) scaffolds via positively charged protonated g-C3N4 nanosheets (pCN). The PG fibers were precoated with graphene oxide (GO) to enable the assembly of pCN on the surface through electrostatic interactions. The Ce6@pCN-GO-PG composite scaffolds exhibited good cytocompatibility and excellent sono-photodynamic activity, leading to distinctly boosted reactive oxygen species (ROS) generation and a 95.8% inactivation rate of breast cancer cells through a synergistic sono-photodynamic process triggered by an 808 nm laser and 1 MHz ultrasound (US) excitation, within the clinical therapeutic dose. The as-developed scaffolds with unique ultrasound cavitation therapeutic effects can be used not only for complete eradication of tumor cells after surgery but also as a cell behavior observation platform of sono-photodynamic cancer therapy.

Despite their impressive plasmonic photocatalytic activity, nanosized silver and silver halides always suffer from serious agglomeration and photocorrosion, thus are severely restricted in the practical wastewater restoration applications. The design and realization of plasmonic heterojunction nanostructures is an effective way to solve this stability problem, yet the ideal plasmonic catalyst dispersion and immobilization remains a great challenge. In this work, a highly immobilized Ag@AgCl/g-C3N4 plasmonic photocatalyst was developed through a rational in-situ implanting approach, in which the Ag can be homodispersely distributed and strongly coupled with prefixed Cl sites on g-C3N4 nanosheets (CNNS). The X-ray diffraction (XRD) pattern, X-ray photoelectron spectroscopy (XPS) spectra and element mapping images clearly proved the homodispersely distribution of nanosized Ag@AgCl on the CNNS. The optimal Ag@AgCl-3/CNNS plasmonic photocatalyst with a narrow band gap of 2.45 eV and large specific surface area of 52.9 m2/g performs well in model pharmaceutical wastewater bleaching reactions under visible light. More importantly, the Ag@AgCl-3/CNNS show good stability compared with the conventional inhomogeneously coupled AgCl/g-C3N4 control as verified by their ultralow silver leakage rate in water (0.00152 mg/g·d, accounts 6.9% that of the control) and a much lower corrosion current density (Icorr = 1.63 vs. 3.45 μA), recorded by Tafel slopes. The synergetic effect of surface plasmon resonance effect of nanosized Ag@AgCl with strong visible light harvesting ability and strong coupling between Ag@AgCl and exfoliated porous g-C3N4 nanosheets can support the fast separation of photogenerated electron–hole pairs, thus significantly improving the photocatalytic efficiency in the bleaching of antibiotic pollutants and bacteria. This work affords the great potential of the rational in-situ implanting design for high-performance and stable plasmonic photocatalysts.

Powerful yet orderly nanostructure lithium-ion batteries (LIBs) are eagerly desired to satisfy the practical application of portable electronics and smart grids. However, the surface re-stacking and surface functionalization on the MXenes in the anode electrode severely restrict the accessibility to electrolyte ions, hindering the full utilization of their intrinsic properties. To address this challenge, we rationally design three-dimensional (3D) Sn@Ti

Efficient utilization of near-infrared (NIR) energy is a high-priority in the field of energy and nanomedicine, yet the design and assembly of metal-free NIR-driven photocatalysts with biologic safety and good stability is still challenging. Herein, we report the design and synthesis of high-quality metal-free NIR-driven photocatalysts by judiciously combining the US Food and Drug Administration (FDA)-approved clinically useable Chlorin e6 (Ce6) as NIR photosensitizer and the protonated two-dimensional (2D) graphitic carbon nitride (g-C3N4) for the first time. Under the irradiation of visible light (>420 nm) and NIR light (>780 nm), the Ce6@pCN prepared here showed remarkable 10-fold and 174-fold high H2 evolution performance compared with bulk g-C3N4 (1275.6 vs. 127.1 μmol h−1 g−1; 312.6 vs. 1.8 μmol h−1 g−1) and excellent stability. Owing to the high efficiency, stability and nontoxicity, this protonated 2D g-C3N4 sensitized with Ce6 is promising for a wide-range of applications in energy, environmental and biological fields.

Polymer graphitic carbon nitride (g-C3N4) materials have attracted growing interest owing to their impressive applicability in photocatalysis and optoelectronic devices. However, further applications of g-C3N4 materials are greatly restricted by their chemical inertness and insolubility in most solvents. Regarding the rising prospect of g-C3N4 nanosheets in the biomedical field, high solubility and biocompatibility are required for the further development of g-C3N4 materials. In this study, a simple one-step thermal polymerization method was designed to prepare fast-soluble mesoporous g-C3N4 nanosheets by using NH4HSO4 as the critical adjuvant. The products, especially the optimal g-C3N4 NSs-4, showed impressive solubility, biocompatibility and partial biodegradability. The enriched surface hydrophilic groups (–NH2 and –OH) may contribute to improving the solubility of g-C3N4 nanosheets, while the partial biodegradability can be ascribed to the presence of the disulfide bond in the g-C3N4 framework. In this system, the NH4HSO4 adjuvant acted not only as O and S sources, but also as a bubbling agent that endows the g-C3N4 a porous structure with greatly enlarged specific surface area and high separation efficiency of photogenerated electron-hole pairs. These integrative positive factors also greatly contributed to the photocatalytic activity of the g-C3N4 nanosheets. This facile, economic and general fabrication strategy for mesoporous, fast-soluble and biocompatible g-C3N4 with superior visible-light photocatalytic activity is promising in environmental, energy and biomedical fields.