Xiangyu Chen,Jiahua Ma,Xiaoshuai Sun,Chuanshan Zhao,Jiehua Li,Hui Li
This paper proposes a different strategy for deriving carbon materials from biomass, abandoning traditional strong corrosive activators and using a top−down approach with a mild green enzyme targeted to degrade the pectin matrix in the inner layer of pomelo peel cotton wool, inducing a large number of nanopores on its surface. Meanwhile, the additional hydrophilic groups produced via an enzymatic treatment can be used to effectively anchor the metallic iron atoms and prepare porous carbon with uniformly dispersed Fe−Nxstructures, in this case optimizing sample PPE−FeNPC−900’s specific surface area by up to 1435 m2g−1. PPE−FeNPC−900 is used as the electrode material in a 6 M KOH electrolyte; it manifests a decent specific capacitance of 400 F g−1. The assembled symmetrical supercapacitor exhibits a high energy density of 12.8 Wh kg−1at a 300 W kg−1power density and excellent cycle stability. As a catalyst, it also exhibits a half−wave potential of 0.850 V (vs. RHE) and a diffusion-limited current of 5.79 mA cm−2at 0.3 V (vs. RHE). It has a higher electron transfer number and a lower hydrogen peroxide yield compared to commercial Pt/C catalysts. The green, simple, and efficient strategy designed in this study converts abundant, low−cost waste biomass into high-value multifunctional carbon materials, which are critical for achieving multifunctional applications.Keywords:pomelo peel;enzymatic treatment;Fe−Nx;supercapacitors;ORR
Zhenrui Li,Zhihui Wang,Linxin Dai,Jianfeng Ma,Xing’e Liu
A lignin-based Fe/N co-doped carbonaceous catalyst was synthesized via freeze-drying followed by pyrolysis to activate peroxymonosulfate (PMS) for efficient degradation of bisphenol A (BPA). The Fe/N co-doped biochar exhibited a high specific surface area (364.84 m 2 /g), hierarchical porous structures, and abundant oxygen-containing functional groups (hydroxyl and carboxyl groups), which enhancing the dispersion of Fe 3 O 4 nanoparticle and exposure of catalytic site. The Fe 8 -N 10 -C/PMS system achieved 100 % BPA degradation within 20 min with a corresponding first-order reaction rate constant ( k obs ) of 0.4056 min −1 , which outperformed most reported catalysts in efficiency. Quenching and EPR analyses revealed that both free radicals ( • OH, SO 4 •− , and O 2 •− ) and non-radical ( 1 O 2 ) were rate-limiting steps, while graphitic N and Fe-N x structures facilitated direct electron transfer from BPA to PMS in electrochemical tests. XPS results confirmed that pyrrolic N, rather than pyridinic N, played a crucial role in forming the Fe-N x structure. Moreover, the catalyst showed excellent stability, regeneration capability, and adaptability under diverse conditions, highlighting the potential of the Fe-N-C/PMS system for practical wastewater treatment applications.
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