Facile fabrication of Ag/PANI/g-C3N4 composite with enhanced electrochemical performance as supercapacitor electrode

Impact-resistant supercapacitor by hydrogel-infused lattice

The safety of energy storage devices is increasingly crucial due to the growing requirements for application under harsh conditions. Effective methods for enhancing robustness without compromising functionality are necessary. Here we present an impact-resistant, ready-to-use supercapacitor constructed from self-healable hydrogel electrolyte-infused lattice electrodes. Three-dimensional-printed carbon-coated silicon oxycarbide current collectors provide mechanical protection, with compressive stress, Young's modulus, and energy absorption up to 70.61 MPa, 2.75 GPa, and 92.15 kJ/m3, respectively. Commercially viable polyaniline and self-healable polyvinyl alcohol hydrogel are used as active coatings and electrolytes. I-wrapped package structured supercapacitor electrode exhibits a static specific capacitance of 585.51 mF/cm3 at 3 mA/cm3, with an energy density of 97.63 μWh/cm3 at a power density of 0.5 mW/cm3. It maintains operational integrity under extreme conditions, including post-impact with energy of 0.3 J/cm3, dynamic loading ranging from 0 to 18.83 MPa, and self-healing after electrolyte damage, demonstrating its promise for applications in extreme environments.

Bi(Ⅲ) and Ce(Ⅳ) functionalized carbon nitride photocatalyst for antibiotic degradation: Synthesis, toxicity, and mechanism investigations

Graphite-phase carbon nitride (g-C₃N₄) has shown great potential for antibiotic wastewater treatment due to its unique electronic structure and corresponding to visible light. In this study, a series of Bi/Ce/g-C₃N₄ photocatalysts with different doping amount were developed by direct calcination method for Rhodamine B and sulfamethoxazole photocatalytic degradation. The experiment result shows that the photocatalytic performance of Bi/Ce/g-C₃N₄ catalysts were better than that of single component samples. Under the optimal experimental conditions, the degradation rates of RhB (20 min) and SMX (120 min) by 3Bi/Ce/g-C₃N₄ reached 98.3% and 70.5%, respectively. The theoretical calculation results of DFT show that after Bi and Ce doping modification, the band-gap width of g-C₃N₄ is reduced to 1.215 eV and carrier migration rate is greatly improved. The enhanced photocatalytic activity was mainly attributed to the capture of electrons after doping modification, which inhibition of photogenerated carriers recombination and reduced the gap width. The cyclic treatment experiment of sulfamethoxazole showed that Bi/Ce/g-C₃N₄ catalysts had good stability. Ecosar evaluation and leaching toxicity test showed that Bi/Ce/g-C₃N₄ can be safely used for wastewater treatment. This study provides a perfect strategy for modifying g-C₃N₄ and a new way to improve the photocatalytic performance.

Nitrogen-rich accordion-like lignin porous carbon via confined self-assembly template and in-situ mild activation strategy for high-performance supercapacitors

Nitrogen-doped porous carbons have emerged as promising electrode materials for supercapacitors. However, the precise control of carbon geometry and the effective doping method remain challenging. Herein, a confined self-assembly template and in-situ mild activation strategy is proposed to prepare cubic lignin composite precursor, followed by co-pyrolysis with melamine at a high temperature for nitrogen-doped hierarchical porous carbons (N-HPLCs). The zinc oxalate template has the coupling effect of confinement and mild activation during carbonization, which not only prevents the restacking of the carbon matrix but also generates zinc cyanamide intermediate to avoid excessive loss of nitrogen species. The optimized N-HPLCs exhibit an accordion-like framework with interconnected porous sheets, ultrahigh edge-nitrogen doping level (up to 12.20 at.%), and a total nitrogen doping level of 14.09 at.%. Consequently, it shows a high gravimetric capacitance of 354 F/g at 0.2 A/g, an extraordinary surface-area-normalized capacitance of 82.1 ± 0.2 μF/cm², and good rate capability in supercapacitor applications. Moreover, the fabricated coin-type symmetric supercapacitor displays a high energy density of 12.9 Wh/kg at 161.9 W/kg and superior cycling stability with a 99.5% capacitance retention after 16,000 cycles at 2.0 A/g. This work offers a novel method for preparing nitrogen-enriched lignin-derived carbon for high-performance supercapacitors.

Prolific intercalation of VO2 (D)/polypyrrole/g-C3N4 as an energy storing electrode with remarkable capacitance

VO2 (D)/polypyrrole/g-C3N4 composites are synthesized through in situ chemical oxidation polymerization, and used as an electrode material for excellent energy storage.

High-power-energy proton supercapacitor based on interface-adapted durable polyaniline and hexagonal tungsten oxide

Supercapacitors are high power energy storage devices, however, their application are remain limited by the low energy density. Developing high capacity electrode materials and constructing devices with high operating voltage are effective ways to solve this problem. Herein, performance of polyaniline (PANI) electrode materials is dramatically enhanced by engineering robust PANI/carbon interfaces, through assembling PANI nanorod array on rose petals derived carbon network (RPDCN). The structure of the PANI is optimized by adjusting the concentration of the aniline precursor. The unique structure enables the prepared PANI/RPDCN composite show a high capacitance of 636 F g^-1 at 0.5 A g^-1, based on the total weight of PANI and RPDCN substrate. The robust interface effectively prolonged the composite electrode stably cycled for over 2000 cycles at 2 A g^-1 with a capacity retention of 89%. When coupled with a hexagonal tungsten oxide (h-WO₃) anode, a high-power asymmetric proton supercapacitor with high energy densities (29.0 Wh kg^-1/0.61 kW kg^-1 and 21.4 Wh kg^-1/19.51 kW kg^-1) was assembled. This work provides an effective and eco-friendly route toward superior PANI electrodes and proposes a promising high-power energy storage system using proton as working ion.

High crystallinity and conjugation promote the polarization degree in O-doped g-C3N4 for removing organic pollutants

High crystallinity and extended conjugated system improve the polarization of O-doped g-C₃N₄, which efficiently promotes carrier separation.

Surface defective g-C3N4-xClx with unique spongy structure by polarization effect for enhanced photocatalytic removal of organic pollutants

Natural sponge is an ancient marine organism with a single lamellar structure, on which there are abundant porous channels to compose full-fledged spatial veins. Illumined by the natural spongy system, herein, the Cl doped surface defective graphite carbon nitride (g-C₃N_4-xCl_x) was constructed through microwave etching. In this process, microwave with HCl was employed to produce surface defects and peel bulk g-C₃N₄ to form natural spongy structured g-C₃N_4-xCl_x with three-dimensional networks. The spongy structure of the photocatalyst could provide abundant and unobstructed pathways for the transfer and separation of electron-hole pairs, and it was beneficial for photocatalytic reaction. The spongy defective g-C₃N_4-xCl_x achieved excellent degradation of diclofenac sodium (100%), bisphenol A (88.2%), phenol (85.7%) and methylene blue (97%) solution under simulated solar irradiation, respectively. The chlorine atoms were introduced into the g-C₃N₄ skeleton in microwave field with HCl, forming C-Cl bonds and surface polarization field, which could significantly accelerate the separation of photogenerated electrons and holes. As an efficient and universal approach, microwave etching can be generally used to create surface defects for most photocatalysts, which may have potential applications in environmental purification, energy conversion and photodynamic therapy.

Bifunctional Z-Scheme Ag/AgVO3/g-C3N4 photocatalysts for expired ciprofloxacin degradation and hydrogen production from natural rainwater without using scavengers

To maximize the employment of sustainable solar energy in treating the recalcitrant pollutant and hydrogen energy production, the development of a highly efficient photocatalyst is desirable. Herein, a Z-scheme Ag/AgVO₃/g-C₃N₄ photocatalyst was synthesized via a wet-impregnation method. The amount of Ag/AgVO₃ deposited onto g-C₃N₄ has a significant effect on the photocharge carrier separation and migration of the as-developed Z-scheme photocatalyst. It was found that 0.5 wt % Ag/AgVO₃/g-C₃N₄ photocatalyst exhibited a profound photocatalytic degradation performance with 82.6% ciprofloxacin removal and 3.57 mmol/h of hydrogen produced from natural rainwater under visible-light irradiation. Additionally, the apparent quantum efficiency (AQE) of this sample was 9.95% at 420 nm which is four times higher than the pure sample. The remarkable photocatalytic performance was attributed to the enhanced crystallographic structure, evidently from the XRD and XPS analysis. Moreover, the intimate contact between Ag/AgVO₃ and g-C₃N₄ nanoparticles allows the smooth photocharge carrier separation and migrations, resulting in superior photocatalytic performance in comparison to the pure samples. Interestingly, the profound photocatalytic activity demonstrated here was achieved without the addition of any sacrificial reagents. This work demonstrates the feasibility of utilizing visible-light-driven photocatalysts in treating the recalcitrant antibiotic pollutants and producing hydrogen from natural rainwater.

Sensitive detection of carcinoembryonic antigen (CEA) by a sandwich-type electrochemical immunosensor using MOF-Ce@HA/Ag-HRP-Ab2 as a nanoprobe

Sandwich-type electrochemical immunosensor was one of the main methods for detecting carcinoembryonic antigen (CEA). In this work, using Ce-MoF as the skeleton precursor, hyaluronic acid (HA) was coated on the surface of Ce-metal organic framework (Ce-MoF), which loaded with silver nanoparticles (Ag NPs) and horseradish peroxidase (HRP) to catalyze H₂O₂ and double amplified the current signal. Thus, a sensitive sandwich-type electrochemical immunosensor (Ce-MoF@ HA/Ag-HRP) was designed to detect carcinoembryonic antigen (CEA). The designed immunosensor used Au NPs to enhance the ability of attach more the first antibody (Ab₁). This was due to Au NPs had good electrical conductivity and biocompatibility to accelerate electron transfer on the surface of the electrode. HA was riched in -COOH, -OH and had excellent biocompatibility, which can carry more Ag NPs to catalyze H₂O₂. Finally, the prepared sandwich-type electrochemical immunosensor had excellent biocompatibility and great catalytic performance. The immunosensor can be tested within 30 min and the logarithm of the current signal and CEA concentration showed a broad linear response range of 1 pg ml^-1-80 ng ml^-1, and the detection limit of CEA was 0.2 pg ml^-1. More importantly, the proposed immunosensor had good reproducibility, selectivity, stability and without matrix effect. This confirmed that the proposed immunosensor had broad prospects in early clinical trials.

Immobilized BiCl3@Bi@g-C3N4 on one-dimensional multi-channel carbon fibers as heterogeneous catalyst for efficient CO2 cycloaddition reaction

A novel heterogeneous catalyst (BBCNC), where the Bi, BiCl₃ and g-C₃N₄ were deposited on one-dimensional multi-channel carbon fibers (CNFs), was developed and characterized.

Electrochemical Fingerprint of Arsenic (III) by Using Hybrid Nanocomposite-Based Platforms

Arsenic, one of the most abundant mineral and also one to the most toxic compounds. Due to its high toxicity sensitive analytical methods are highly important, taking into account that the admitted level is in the range of µg L^-1. A novel and easy to use platform for As(III) detection from water samples is proposed, based on gold and platinum bi metallic nanoparticles and a conductive polymer (polyaniline). The electrochemical detection was achieved after optimization of cathodic pre-concentration and stripping parameters by square wave anodic stripping voltammetry at modified screen-printed carbon-based electrochemical cells, proving its applicability for disposable and cost-effective in situ analysis of arsenic.