Nitrogen-doped lignin-derived electrode materials for supercapacitors were prepared using the domain-limited effect.

Supercapacitors, pivotal in mitigating the energy crisis stemming from dwindling fossil fuel reservoirs, necessitate meticulous consideration of electrode material preparation. While lignin-derived carbon materials sourced sustainably exhibit commendable potential as electrode materials, their intrinsic low capacitance limits widespread utilization. Herein, nitrogen atom doping of lignin (CNL) was accomplished employing a chemical modification technique employing cyanuric chloride as a dopant. The resultant nitrogen content measured at 2.85 %. Subsequent to CNL carbonation, the generated C3N4 was selectively confined to the internal surface of the CNLMS-800 through a domain-limited activation method, thereby rendering it suitable for deployment as a supercapacitor electrode material. CNLMS-800 manifests a substantial specific surface area of 1778.0 m2 g-1 and a concomitantly diminutive pore size of 2.6 nm. Noteworthy, the specific capacitance of CNLMS-800 attains 473.0 F g-1 at a current density of 0.5 A g-1 in a 6 M KOH electrolyte. The resultant energy density reaches 39.0 Wh kg-1 at a power density of 338.0 W kg-1. Crucially, even after 20,000 charge/discharge cycles at a current density of 10 A g-1, the capacitance retention attains an impressive 87.5 % in the KOH electrolyte. This innovative utilization of sustainable resources for electrode fabrication epitomizes a seminal advancement in the field of energy technology.

Controllable synthesis of Fe3C-reinforced petal-like lignin microspheres with boosted electrochemical performance and its application in high performance supercapacitors.

One more effective measure to solve the energy crisis caused by the shortage of fossil energy is to convert natural renewable resources into high-value chemical products for electrochemical energy storage. Lignin has broad application prospects in this field. In this paper, three kinds of lignin with different molecular weights were obtained by the ethanol/water grading of Kraft lignin (KL). Then, different surface morphology lignin microspheres were prepared by spray drying. Finally, petal-like microspheres were successfully prepared by mixing and grinding the above four kinds of surface morphology lignin microspheres with potassium ferrate and cyanogen chloride and carbonizing at 800 °C and were later used as electrode materials for supercapacitors. Compared with the other microspheres, LMS-F3@Fe3C has the highest specific surface area (1041.42 m2 g-1), the smallest pore size (2.36 nm) and the largest degree of graphitization (ID/IG = 1.06). At a current density of 1 A g-1, the maximum specific capacitance is 786.7 F g-1. At a power density of 1000 W kg-1, the high energy density of 83.3 Wh kg-1 is displayed. This work provides a novel approach to the modulation of surface morphology and structure of lignin microspheres.

Promising Rare-Earth-Doped, Electrospun, ZnO Nanofiber N-type Semiconductor for Betavoltaic Batteries.

Betavoltaic batteries, as a kind of ultimate battery, have attracted much attention. ZnO is a promising wide-bandgap semiconductor material that has great potential in solar cells, photodetectors, and photocatalysis. In this study, rare-earth (Ce, Sm, and Y)-doped ZnO nanofibers were synthesized using advanced electrospinning technology. The structure and properties of the synthesized materials were tested and analyzed. As betavoltaic battery energy conversion materials, the results show that rare-earth doping increases the UV absorbance and the specific surface area and slightly reduces the band gap. In terms of electrical performance, a deep UV (254 nm) and X-ray source (10 keV) were used to simulate a radioisotope ß-source to evaluate the basic electrical properties. Among them, the output current density of Y-doped ZnO nanofibers can reach 87 nA·cm-2, which is 78% higher than that of traditional ZnO nanofibers, by deep UV. Besides, the photocurrent response of Y-doped ZnO nanofibers is superior to that of Ce-doped and Sm-doped ZnO nanofibers by soft X-ray. This study provides a basis for rare-earth-doped ZnO nanofibers as energy conversion devices used in betavoltaic isotope batteries.

Preparation of the porous carbon-based solid acid from starch for efficient degradation of chitosan to D-glucosamine.

Effective degradation of chitosan to D-glucosamine is considered to make a great contribution for the development of the medical industry. To address this issue, a porous carbon-based solid acid catalyst (PCSA) functionalized with -OH, -COOH and -SO3H groups was successfully prepared. Typically, the physicochemical properties of PCSA were deeply determined by a series of characterization technique including FT-IR, TGA, RM, NH3-TPD, SEM and Element Analysis. Moreover, the catalytic performances of PCSA towards to D-glucosamine production from chitosan were evaluated. In particular, the effects of catalyst acid density, ratio of acidic groups, chitosan concentration, reaction temperature, reaction time and catalyst dosage on the yield of D-glucosamine were investigated in detail. Interestingly, the experimental results indicated that a yield of D-glucosamine as high as 90.5% was achieved, and no obvious deactivation occurred even after six consecutive cycles. In light of the advantages of superior activity/recyclability and low cost, the starch-derived solid acid developed in this work might possess the broad industrial application prospects.

Controllable synthesis of pomelo peel-based aerogel and its application in adsorption of oil/organic pollutants.

Oil/water separation is a field of high significance as it might efficiently resolve the contamination of industrial oily wastewater and other oil/water pollution. In this paper, an environmentally-friendly hydrophobic aerogel with high porosity and low density was successfully synthesized with renewable pomelo peels (PPs) as precursors. Typically, a series of sponge aerogels (HPSA-0, HPSA-1 and HPSA-2) were facilely prepared via high-speed dispersion, freeze-drying and silanization with methyltrimethoxysilane. Indeed, the physical properties of aerogel such as density and pore diameter could be tailored by different additives (filter paper fibre and polyvinyl alcohol). Hence, their physico-chemical properties including internal morphology and chemical structure were characterized in detail by Fourier transform infrared, Brunauer-Emmett-Teller, X-ray diffraction, scanning electron microscope, Thermal gravimetric analyzer (TG) etc. Moreover, the adsorption capacity was further determined and the results revealed that the PP-based aerogels presented excellent adsorption performance for a wide range of oil products and/or organic solvents (crude oil 49.8 g g-1, soya bean oil 62.3 g g-1, chloroform 71.3 g g-1 etc.). The corresponding cyclic tests showed the absorption capacity decreased slightly from 94.66% to 93.82% after 10 consecutive cycles, indicating a high recyclability.