Lee Jaekwang, Lee Heesoo
School of Materials Science and Engineering, Pusan National University, Busan 46241, Republic of Korea.
Nanomaterials (Basel). 2024 Dec 13;14(24):2004. doi: 10.3390/nano14242004.
The catalytic activity of Ni-Fe oxide embedded in CNTs was investigated in terms of valence states and active oxygen species. Ni-Fe oxides were prepared by the sol-gel combustion process, and Ni-Fe oxides embedded in CNT catalysts were synthesized by the catalytic chemical vapor deposition (CCVD) method. The lattice structure of the Ni-Fe oxide catalysts was analyzed, and the lattice distortion was increased with the addition of Fe. The specific surface areas and pore structures of the Ni-Fe oxides embedded in CNTs were determined through the BET method. The nano-sized Ni-Fe oxides embedded in CNTs were observed using morphology analysis. The crystallinity and defects of CNTs were analyzed by Raman spectroscopy, and the I/I ratio of NiFeO/CNT was the lowest at 0.36, representing the high graphitization and low structural defects of the CNT surface. The valence states of Fe and Ni were changed by the interaction between catalysts and CNTs. The redox property of the catalysts was evaluated by H-TPR analysis, and the H consumption of NiFeO/CNT was the highest at 2.764 mmol/g. The catalytic activity of Ni-Fe oxide embedded in CNT exhibited much higher activity than Ni-Fe oxide for the selective catalytic reduction of NOx with NH3 in the temperature range of 100 °C to 450 °C.
从价态和活性氧物种的角度研究了嵌入碳纳米管中的镍铁氧化物的催化活性。通过溶胶-凝胶燃烧法制备镍铁氧化物，并采用催化化学气相沉积（CCVD）法合成嵌入碳纳米管催化剂中的镍铁氧化物。分析了镍铁氧化物催化剂的晶格结构，发现随着铁的添加，晶格畸变增加。通过BET法测定了嵌入碳纳米管中的镍铁氧化物的比表面积和孔结构。利用形态分析观察了嵌入碳纳米管中的纳米级镍铁氧化物。通过拉曼光谱分析了碳纳米管的结晶度和缺陷，NiFeO/CNT的I/I比最低，为0.36，表明碳纳米管表面具有高石墨化程度和低结构缺陷。催化剂与碳纳米管之间的相互作用改变了铁和镍的价态。通过H-TPR分析评估了催化剂的氧化还原性能，NiFeO/CNT的H消耗量最高，为2.764 mmol/g。在100℃至450℃的温度范围内，嵌入碳纳米管中的镍铁氧化物对于用NH3选择性催化还原NOx的催化活性比镍铁氧化物高得多。
