Mn-Ce-M复合改性无硅残渣炭催化剂的NH3选择性还原NO性能研究

Study on the Selective Catalytic Reduction of NO by NH3 over Silicon-free Residue Carbon Catalysts Doped with Mn-Ce-M

生物质作为极具潜力的可再生能源,其热解制油技术备受关注,副产物残渣炭的高值化利用是当下重要的研究内容之一.脱硅处理不仅可实现硅的资源化利用,同时可以实现炭材料的结构改性.我们开展了残渣炭煮溶脱硅研究,并基于最佳脱硅方式,探究了不同金属M(M:Ho、Sb、La、Nd)对无硅残渣炭(FRB)催化剂脱硝性能的影响规律.结果表明:煅烧预处理结合煮溶脱硅可以脱除99%以上的SiO_(2),脱硅的同时理化性质显著改善,表现出较大的比表面积(1923 m^(2)/g)、丰富的介/微孔结构以及表面含氧官能团,并促进了催化剂的SCR反应活性(250℃时NO_(x)脱除率可达100%).此外,Ho改性无硅残渣炭脱硝催化剂具有最好的低温脱硝活性,在200~300℃范围内保持80%以上的脱硝效率.表征结果显示,MnCeHo/FRB催化剂具有较强的表面酸性和氧化还原性,活性组分在载体上均匀分散,且表面化学吸附氧较为丰富.此外,In-situ DRIFTs实验表明MnCe/FRB催化剂表面同时存在E-R和L-H机理,但E-R机理占主要地位.

As a potential renewable energy,the technology of producing oil via biomass pyrolysis has attracted widespread attention.The high-value utilization of by-product residue carbon is recognized as a significant research content at present.Desiliconization not only promotes the resource utilization of silicon,but also the structure of carbon materials is greatly improved.In this paper,the research on desiliconization of residue carbon by boilingdissolution was carried out.Based on the optimal desiliconization method,the effect of different metal M(M:Ho/La/Sb/Nd)on the denitration performance of silicon-free residue carbon(FRB)catalyst was explored.The results illustrated that more than 99%SiO_(2) can be removed by the combination of calcination pretreatment and boilingdissolution desiliconization,while the physicochemical properties of residue carbon were significantly improved after desiliconization.Residual carbon treated with the optimal method exhibited a large specific surface area(1923 m^(2)/g),rich mesoporous/microporous structures and more oxygen-containing functional groups on the surface,which promoted the SCR activity of the catalysts(the NOx removal rate of FRB was 100%at 250℃).In addition,Ho-modified silicon-free residue carbon denitrification catalyst(MnCeHo/FRB)displayed the best low-temperature activity,maintaining more than 80%NO_(x) removal rate in the temperature range of 200~300℃.The characterization results revealed the strong surface acidity and redox properties of the MnCeHo/FRB catalyst,as well as the uniformly dispersed active components and abundant surface chemisorbed oxygen.In situ DRIFTs experiments certified that both of E-R and L-H mechanisms existed on the surface of MnCe/FRB catalyst,while E-R mechanism was dominant.