硝酸胶溶剂对CuO/HZSM-5成型催化剂性能的影响

催化剂CuO/HZSM-5在氧化亚氮(N₂O)催化分解领域有着重要地位,完成对催化剂成型条件的探索是其工业实际应用的重要步骤。在CuO/HZSM-5成型过程中,胶溶剂的用量对成型催化剂的机械强度,催化活性以及其他物化性质有重要的影响。通过机械强度测定、活性评价、X射线衍射分析(XRD)、孔结构分析、氨气程序升温吸附脱附分析(NH₃-TPD)、氢气程序升温还原分析(H₂-TPR)等手段对催化剂性能进行分析。机械强度测定与NH₃-TPD分析结果显示,胶溶剂用量对成型催化剂机械强度和酸量影响较大,胶溶剂用量为体积分数2%时,机械强度最高为135.8 N·cm^-1,而催化剂酸量在胶溶剂用量为体积分数7%时最高。XRD与孔结构分析结果显示胶溶剂用量由0增长至体积分数7%,催化剂的孔容积改变幅度较小,但比表面积由277 cm²·g^-1增至293 cm²·g^-1,HZSM-5的特征峰变化较小。活性评价与H₂-TPR分析结果显示,胶溶剂用量为0的催化剂与添加胶溶剂后的成型催化剂,N₂O完全分解的温度提高幅度最大为20 ℃,活性下降,且H₂-TPR中还原峰提高幅度最大为27 ℃,可还原性变差。而胶溶剂用量由体积分数2%提高至7%,成型催化剂CuO/HZSM-5的催化活性以及可还原性差异较小。

Effect of nitric acid on properties of CuO/HZSM-5 extrudate catalysts

CuO/HZSM-5 plays an important role in the catalytic decomposition of nitrous oxide (N₂O).During the shaping process of CuO/HZSM-5,the amount of adhesive solvent had an important influence on the mechanical strength,catalytic activity and other physicochemical properties of the forming catalyst.In this study,the performance of the catalyst was analyzed by mechanical strength determination,activity evaluation,X-ray diffraction analysis (XRD),pore structure analysis,ammonia gas temperature programmed adsorption desorption analysis (NH₃-TPD) and hydrogen gas temperature programmed reduction analysis (H₂-TPR).The mechanical strength measurement and NH₃-TPD analysis results showed that the dosage of adhesive solvent had a great influence on the mechanical strength and acid content of the molding catalysts.The highest mechanical strength was 135.8 N·cm^-1 when the dosage of adhesive solvent was 2%.The catalyst acid content was the highest when the solvent content was 7%.XRD and pore structure analysis results showed that the solvent content of the adhesive increased from 0 to 7%,the pore volume of the catalyst changed slightly,but the specific surface area increased from 277 cm²·g^-1 to 293 cm²·g^-1,and the characteristic peaks of HZSM-5 also had a small influence.The results of activity evaluation and H₂-TPR analysis showed that for the catalyst with a solvent content of 0 and the forming catalyst with the addition of the solvent,the temperature of N₂O complete decomposition increased by up to 20 ℃,and the activity decreased.In addition,the reduction peak in H₂-TPR increased by up to 27 ℃,and the reductibility became worse.However,the dosage of colloidal solvent increased from 2% to 7%,and the catalytic activity and reducibility of CuO/HZSM-5 were less different.