改性硫化钼催化剂协同低温等离子体转化H_(2)S-CO_(2)酸气制合成气的研究

Combination of modified molybdenum sulfide catalyst and non-thermal plasma for syngas production from H_(2)S-CO_(2)acid gas

以低温等离子体和催化剂耦合法将H_(2)S和CO_(2)混合酸气一步转化为合成气,既完成了两者清洁化处理,又实现了资源化利用,是一条制备合成气的新路线。本研究采用铜、锌为助剂对硫化钼催化剂改性,显著提升了其催化H_(2)S-CO_(2)制合成气反应性能。结合多种分析表征手段对比两种助剂引入后对硫化钼催化剂结构、组成、形貌、化合价态等物化特征的影响。通过控制低温等离子体放电条件,深入探究了两种助剂对低温等离子体下催化转化H_(2)S和CO_(2)酸气制合成气的反应性能影响规律和关键因素。研究发现,引入铜、锌助剂后,硫化钼活性相粒径减小且分散度高,提供了更多活性位点。同时也增强了对H_(2)S和CO_(2)分子吸附强度,从而更利于H_(2)S和CO_(2)分子的吸附活化,揭示出低温等离子体与改性硫化钼催化剂协同反应的构效关联。有关理论研究丰富拓展了低温等离子体-催化协同理论,并为改性硫化钼材料的合成提供借鉴。

The petrochemical,natural gas,and coal chemical industries will produce a large number of hydrogen sulfide(H_(2)S)and carbon dioxide(CO_(2))mixed acid gas,causing serious damage to the environment and human health.At present,the most widely used treatment technology for H_(2)S-containing mixed acid gas is the Claus process.Nevertheless,the Claus process is unable to achieve the recovery of hydrogen sources and the reduction of CO_(2)emissions,resulting in a considerable quantity of CO_(2)being discharged directly into the atmosphere,which has a detrimental impact on the global climate.Carbon,hydrogen,sulfur and other elements play an important role in the field of energy.Therefore,it is of great importance to explore new methods for the utilization of H_(2)S and CO_(2)mixed acid gas to save energy,protect the environment and achieve green and low-carbon development.A non-thermal plasma-catalysis method is used to convert H_(2)S and CO_(2)acid gas into syngas in a single step.This method achieves both the clean treatment of waste gas and its resource utilization,making it a novel route for syngas preparation.The non-thermal plasma contains high-energy electrons that can transfer energy to H_(2)S and CO_(2)molecules in the form of inelastic collisions,thereby exciting them into free radicals,ions,excited molecules and atoms.Concurrently,the catalyst filled in the discharge gap can facilitate the chemical reactions of these active species.However,the stable molecular structure of H_(2)S and CO_(2)presents a significant challenge to the improvement of energy efficiency,particularly in the context of high conversions of reactive molecule.The development of efficient catalysts is crucial to improve the H_(2)S and CO_(2)conversion.The existing results demonstrate that electrons,photons and strong electric field generated by non-thermal plasma can be used to excite MoS_(2)catalyst to generate highly active electron-hole pairs.These in turn catalyze the conversion of H_(2)S and CO_(2).This study used copper and zinc as promoters to modify the molybdenum sulfide catalyst,and the catalytic performance for the conversion of H_(2)S-CO_(2)to syngas was effectively improved.A detailed comparison was made between the effects of the two promoters on the structure,composition,morphology,valence state,and other physicochemical characteristics of the molybdenum sulfide catalyst using various characterization methods.Furthermore,the influence factors of two types of promoters on the catalytic H_(2)S-CO_(2)conversion was investigated by controlling the discharge conditions.The introduction of copper and zinc promoters was found to result in a reduction in the particle size of the molybdenum sulfide active phase,accompanied by a high degree of dispersion,which in turn led to an increase in the number of active sites.Concurrently,the adsorption strength of H_(2)S and CO_(2)molecules was enhanced,which was conducive to the adsorption and activation of H_(2)S and CO_(2).It revealed the structure-activity relationship between the modified molybdenum sulfide catalyst and plasma synergistic reaction.In addition,the theoretical research has enriched and expanded the theory of non-thermal plasma-catalysis.It has also provided a reference for the synthesis of modified molybdenum sulfide materials.