Li-Yuan Zhang,Meng-Ran Wang,Yan-Qing Lai,Xiao-Yan Li
N-doped microporous carbon as an exceptional metal-free catalyst from waste biomass ( banana peel as representative ) was obtained via fast catalysis carbonization , followed by N-doping modification. The method achieves a relatively high C conversion efficiency of ∼41.9%. The final carbon materials are doped by N (∼3 at.%) and possess high surface area (∼1097 m 2 g −1 ) and abundant micropores . Compared to commercial Pt/C materials, the as-prepared carbon catalyst exhibits a comparable electrocatalytic activity and much better stability. Furthermore, the metal-free catalyst loaded Zn-air battery possesses higher discharge voltage and power density as compared with that of commercial Pt/C. This novel technique can also be readily applied to produce metal-free carbon catalysts from other typical waste biomass (e.g., orange peel, leaves) as the carbon sources. The method can be developed as a potentially general and effective industrial route to transform waste biomass into high value-added microporous carbon with superior functionalities.
Ya Chu,Lin Gu,Xiuping Ju,Hongmei Du,Jinsheng Zhao,Konggang Qu
A composite catalyst was obtained by covalently linking G4-NH2dendrimers and 1,10-phenanthroline-5-carboxylic acid on the surface of carbon powder, and the composite was named as PMPhen/C. In order to improve the catalytic performance of the composite, copper ions (II) were introduced to PMPhen/C by complex to form the PMPhen-Cu/C catalyst. Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) were applied to investigate the surface microstructure and elemental compositions of the catalysts. The results from electrochemical analysis show that PMPhen/C reduced oxygen to hydrogen peroxide (H2O2) through a two-electron transfer process. PMPhen-Cu/C could reduce oxygen to water through a four-electron pathway. Except the slightly lower initial reduction potential, PMPhen-Cu/C has a comparable oxygen reduction ability (ORR) to that of the commercially available Pt/C catalyst, which makes it a potential candidate as the cathodic catalyst in some fuel cells running in neutral medium, such as a microbial fuel cell.Keywords:Polyamidoamine (PAMAM) G4-NH2dendrimers;phenanthroline;covalent link;ORR catalyst
Kun Liu,Yujing Ling,Xianglong Guan,Ke Hu,Angli Zhang,Kaiqi Liu,Haoyi Li,Guangnian Xu,Xu-Cheng Fu
The commercialization of magnesia-air batteries (Mg-air) necessitates the development of highly efficient, cost-effective, and durable electrocatalysts for oxygen reduction reaction (ORR), replacing expensive and unstable precious metal electrocatalysts. A hard template-assisted synthesis of FeCo nanoparticles immobilized on N-doped porous carbon (Fe-Co-C-N) for the ORR is reported. The half-wave potential of Fe-Co-C-N for ORR (E1/2=0.88 V vs. RHE) is elevated by 40 mV compared to that of 20 wt% Pt/C (E1/2=0.84 vs. RHE). The catalyst exhibits exceptional catalytic performance and remarkable stability. The discharge voltage of the Mg-air battery, utilizing Fe-Co-C-N as the cathode catalyst (1.29 V), surpasses that of the battery employing 20 wt% Pt/C as the cathode catalyst (1.28 V). The Mg-air battery with Fe-Co-C-N as the cathode catalyst exhibited excellent discharge stability and maintained a stable discharge for over 200 hours. The present study offers valuable insights into the structural design and regulatory mechanisms governing the performance of M-N-C catalysts in Mg-air batteries.
Jie Huang,Xuejun Liu,Ding Yuan,Xiaolan Chen,Minghui Wang,Meiyue Li,Lixue Zhang
Lignin upgrading to various functional products is promising to realize high-value utilization of low-cost and renewable biomass waste, but is still in its infancy. Herein, using industry waste lignosulfonate as the biomass-based carbon source and urea as the dopant, we constructed a heteroatom-doped porous carbon nanosheet structure by a simple NaCl template-assisted pyrolytic strategy. Through the synergistic effect of the NaCl template and urea, the optimized lignin-derived porous carbon catalyst with high content of active nitrogen species and large specific surface area can be obtained. As a result, the fabricated catalysts exhibited excellent electrocatalytic oxygen reduction activity, as well as good methanol tolerance and stability, comparable to that of commercial Pt/C. Moreover, rechargeable Zn-air batteries assembled with this electrocatalyst have a peak power density of up to 150 mW cm -2 and prominent long-term cycling stability. This study offers an inexpensive and efficient way for the massive production of highly active metal-free catalysts from the plentiful, inexpensive and environmentally friendly lignin, offering a good direction for biomass waste recycling and utilization.
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