Synergistic effect of nitrogen-doped carbon-nanotube-supported Cu-Fe catalyst for the synthesis of higher alcohols from syngas

Heteroatom doping is an attractive approach for improving the properties of carbon materials for various applications. In this study, a series of nitrogen-doped (N-doped) carbon-nanotube-supported Cu-Fe (xCu(n)-Fe-m/yNCNT) catalysts were prepared for CO hydrogenation to higher alcohols. The structural and textural properties of N-doped catalysts were characterized by X-ray diffraction, transmission electron microscopy, hydrogen temperature- programmed reduction, and CO2 temperature-programmed desorption. The results revealed that doping N into CNT supports improved the Cu-Fe dispersion, strengthened the interaction of Cu and Fe species with N-CNT, and introduced many surface-basicity sites. Thus, an improved CO conversion and excellent selectivity to higher alcohols [S(C2+-OH)] were obtained. Furthermore, the selectivity to alcohols [S(ROH)] and S (C2+-OH)/S(MeOH) over the optimized 15Cu(1)-Fe-1/1.3N-CNT catalyst reached 27.2% and 2.2, while the corresponding values were 20.2% and 0.4, respectively, over the catalyst without N doping under identical reaction conditions. The present results on N-CNT supported Cu-Fe catalyst will provide further understanding on the catalyst design for the transformation of syngas to higher alcohols.