Simultaneously realizing enhancement of sensitivity for freshness monitoring and multinomial properties of carrageenan/konjac glucomannan/blueberry anthocyanin-based intelligent film by diatomite.

Here, highly sensitive blueberry anthocyanin (BBA)-induced intelligent indicating films were fabricated by incorporating a novel composite ingredient, diatomite (DA), into a matrix of konjac glucomannan (KGM), carrageenan (CAR) and BBA. We systematically investigated the effects of introducing DA and BBA on the structure, physical properties, colorimetric response, and practical application of the KGM/CAR film. Our findings revealed that the DA particles and BBA were well-distributed in the KGM/CAR matrix through hydrogen bonding interactions. This distribution significantly improved tensile strength, surface hydrophobicity, thermal stability, and barrier properties of the KGM/CAR film. Notably, the KGM/CAR-based intelligent film loaded with 6 % DA exhibited the most optimal properties. Furthermore, DA exhibited a hierarchical porous structure, enabling the KGM/CAR film to detect volatile amines with heightened sensitivity. When applied to monitor shrimp spoilage in transparent plastic packaging, the color of the composite film underwent remarkable changes from bright pink to bluish violet. These color changes correlated well with the total volatile basic nitrogen (TVB-N) and pH changes in the shrimp, as determined by standard laboratory procedures. Our work presents a promising approach to the development of high-performance and intelligent food packaging materials. These materials hold great potential for practical applications in the field of food packaging.

Optimized mesopores enable enhanced capacitance of electrochemical capacitors using ultrahigh surface area carbon derived from waste feathers.

Porous carbons with high specific surface area are critical engineering materials for current electrochemical capacitors (ECs) technology. Controlling the pore size distribution of porous carbons remains a significant challenge as it is a key aspect in many applications. Herein, we synthesized porous carbon as the electrode material of ECs by means of a two-step synthesis procedure using abandoned feathers as carbon precursor and potassium hydroxide as activating agent. The optimal sample (AFHPC-800-1:3) exhibited an ultra-high specific surface area (SBET) of 3474 m2/g and a huge total pore volume (VT) of 1.82 m3 g-1 as well as abundant small mesopores ranging from 2 to 5 nm in size. The ECs based on the AFHPC-800-1:3 electrode exhibited an ultra-high specific capacitance (Csp) of up to 709F g-1 at 0.5 A g-1. More interestingly, a capacitance of 212F g-1 was retained even at 100 A g-1, demonstrating excellent high-rate capacitive performance. Furthermore, the symmetrical capacitor yielded an excellent energy density of 35.1 Wh kg-1 when the specific power density was 625 W kg-1, substantiating the potential of the small mesopores in promoting the overall capacitance and energy density of electrode materials.

Hierarchical hollow-tubular porous carbon microtubes prepared via a mild method for supercapacitor electrode materials with high volumetric capacitance.

In this paper, hollow-tubular porous carbons were synthesized from abundant biomass Cycas fluff (CF) through simple carbonization followed by an NaHCO3 mild activation process. After activation, the tubular structure of the CF was retained, and a hierarchical structure of micropores, mesopores and macropores was formed. When the optimal mass ratio of NaHCO3/CF is 2, the obtained porous carbon CF-HPC-2 sample has a large specific surface area (SSA) of 516.70 m2 g-1 in Brunauer-Emmett-Teller (BET) tests and a total pore volume of 0.33 cm3 g-1. The C, O, N and S contents of CF-HPC-2 were tested as 91.77 at%, 4.09 at%, 3.54 at%, and 0.6 at%, respectively, by elemental analysis. Remarkably, CF-HPC-2 exhibits a high volume capacitance (349.1 F cm-3 at 1 A g-1) as well as a higher rate capability than other biomass carbon materials (289.1 F cm-3 at 10 A g-1). Additionally, the energy density of the CF-HPC-2 based symmetric supercapacitor in 2 M Na2SO4 electrolyte at 20 kW kg-1 is 27.72 W h kg-1. The particular hollow tubular morphology and activated porous structure determine the excellent electrochemical performance of the material. Hence, this synthetic method provides a new way of storing energy for porous carbon as high volumetric capacitance supercapacitor materials.

One-step production of N-O-P-S co-doped porous carbon from bean worms for supercapacitors with high performance.

In recent years, multi-heteroatom-doped hierarchical porous carbons (HPCs) derived from natural potential precursors and synthesized in a simple, efficient and environmentally friendly manner have received extensive attention in many critical technology applications. Herein, bean worms (BWs), a pest in bean fields, were innovatively employed as a precursor via a one-step method to prepare N-O-P-S co-doped porous carbon materials. The pore structure and surface elemental composition of carbon can be modified by adjusting KOH dosage, exhibiting a high surface area (S BET) of 1967.1 m2 g-1 together with many surface functional groups. The BW-based electrodes for supercapacitors were shown to have a good capacitance of up to 371.8 F g-1 in 6 M KOH electrolyte at 0.1 A g-1, and good rate properties with 190 F g-1 at a high current density of 10 A g-1. Furthermore, a symmetric supercapacitor based on the optimal carbon material (BWPC1/3) was also assembled with a wide voltage window of 2.0 V, demonstrating satisfactory energy density (27.5 W h kg-1 at 200 W kg-1) and electrochemical cycling stability (97.1% retention at 10 A g-1 over 10 000 charge/discharge cycles). The facile strategy proposed in this work provides an attractive way to achieve high-efficiency and scalable production of biomass-derived HPCs for energy storage.