Co
3O
4/γ-Al
2O
3 catalysts with variable Co
3O
4 loadings (5–20 wt%) and deposition of 15% Co
3O
4 on La
2O
3/γ-Al
2O
3 were prepared by wet impregnation method. La
2O
3-γ-Al
2O
3 support with variable composition of La
2O
3 (2–6 wt%) were prepared by co-precipitation method. All the catalysts were tested for oxidative dehydrogenation of ethylbenzene with CO
2 as soft oxidant. Among the Co
3O
4/γ-Al
2O
3 catalysts, 15% Co
3O
4/γ-Al
2O
3 has shown good performance and hence this catalyst has been chosen to investigate the effect of La
2O
3 species. CO
2 pulse chemisorption data indicate more amount of CO
2 uptake over 15% Co
3O
4/4%La
2O
3/γ-Al
2O
3 catalyst which clearly indicates that this catalyst exhibits good performance in ethylbenzene dehydrogenation with CO
2 as soft oxidant because of reverse water gas shift reaction. Temperature programmed reduction studies indicate that the Co
3O
4 catalysts follow two step reduction mechanism from Co
3O
4 to CoO and then to Co and La
2O
3 promotional effect is visible through facile reduction of Co
3O
4 species. La
2O
3 doping has a vital influence in getting enhanced ethylbenzene conversion, styrene yield and alleviates catalyst deactivation compared to that of unpromoted Co
3O
4/γ-Al
2O
3 catalyst. TGA studies indicate the presence low amount coke deposition during time-on-stream over 15% Co
3O
4/4%La
2O
3/γ-Al
2O
3 catalyst compared to 15% Co
3O
4/γ-Al
2O
3 catalyst.
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