Xu Liu,Yuheng Zhao,Jun Ma,Yimo Zhang,Hui Zhang,Zhongqing Liu,Yuefeng Liu
The catalytic oxidation of H 2 S into element sulfur using nanocarbon materials is an effective means to solve environmental pollution and realize resource utilization of sulfur. Defect engineering and heteroatom doping are effective strategies for tuning the electronic structure of carbon materials to enhance their catalytic performance. Therefore, rationally exploiting the synergistic effects between defects and heteroatom sites, and elucidating the underlying catalytic mechanisms are essential for the development of high-performance carbon-based catalysts. In this study, we design and synthesize a series of N-doped carbon catalysts containing structural defects, which exhibit significantly enhanced desulfurization performance. Experimental results demonstrate that the NDC-700 catalyst exhibits excellent catalytic activity (95.0% H 2 S conversion and 94.4% S selectivity at 190 °C) and stability (>80 h) while maintaining high performance with high O 2 partial pressures and in the presence of impurity gases such as steam, CO 2 , and CO under mild conditions in continuous mode (≤ 200 °C). XPS analysis, kinetic studies, and oxygen activation experiments reveal that the catalytic performance improves with increasing defect density, despite a decrease in pyridinic N content. DFT calculations further indicate that defect structures substantially alter the local charge distribution around pyridinic N sites, promoting the adsorption and activation of H 2 S and O 2 , ultimately improving catalytic performance. This study elucidates the synergistic interaction between defects and N sites, and further confirms the critical role of defects in enhancing the catalytic function of N-doped carbon materials.
Gel polymer electrolyte (GPE) based on polymer matrix of lignocellulose and gelatinized potato starch is prepared, and elemental sulfur is introduced as an additive for the first time. The polymer matrix has shown excellent performances including liquid electrolyte uptake, tensile strength and thermal stability. The ionic conductivity and electrochemical stability window of the corresponding GPE are improved with the introduction of the elemental sulfur. Furthermore, the addition of elemental sulfur can be reduced into short-chain Li 2 S and Li 2 S 2 on the surface of lithium anode to further elevate the capacity of battery. Meanwhile, the short-chain Li 2 S and Li 2 S 2 in the solid electrolyte interphase (SEI) film on the surface of lithium metal can improve SEI’s mechanical properties and the interface compatibility between GPE and lithium metal. The multi-component synergistic effect of GPE provides the battery with superior cycle stability and excellent electrochemical performances. Bio-based GPE will exhibit a promising and alternative way for the practical application of lithium–sulfur batteries.
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