Waste eggshell to valuable Co3O4/eggshell material as an efficient catalyst for catalytic decomposition of N2O under simulated real tail gases.

• Eggshell is an effective support to prepare Co 3 O 4 -based catalyst for N 2 O removal. • Co 3 O 4 /eggshell-DP exhibits much higher specific activity than Co 3 O 4. • Co 3 O 4 /eggshell-DP displays outstanding stability and anti-poisoning property. • Co 3 O 4 /eggshell-DP shows a close incorporation between CaCO 3 and Co 3 O 4. Co 3 O 4 shows excellent catalytic activity for N 2 O decomposition, in which it is urgently needed to develop novel efficient catalysts/supports with cheap and environmentally-friendly properties. Herein, Co 3 O 4 nanoparticles decorated eggshell catalysts (Co 3 O 4 /eggshell-GR, Co 3 O 4 /eggshell-IM, and Co 3 O 4 /eggshell-DP) were prepared using simple grinding, impregnation, and deposition-precipitation methods, where waste eggshells were used as an effective support and reaction-promoter. The results indicated that the preparation methods significantly influenced the catalytic activity of Co 3 O 4 /eggshell catalysts; the highest activity was obtained over the Co 3 O 4 /eggshell-DP. The activity of Co 3 O 4 /eggshell-DP was comparable to that of pure Co 3 O 4. More importantly, its specific activity was about 7.3 times that of Co 3 O 4 at 400 °C. The examined Co 3 O 4 /eggshell-DP also displayed outstanding stability and anti-poisoning property in NO, O 2 , and/or H 2 O-containing atmospheres. It was also verified that the excellent activity of Co 3 O 4 /eggshell-DP correlated with the unique structure of the eggshell and the close incorporation between CaCO 3 and Co 3 O 4. The Co 3 O 4 /eggshell-DP catalyst owned abundant Co 3 O 4 nanoparticles, more Co3+ species, and excellent redox performance, promoting the conversion of N 2 O at a lower temperature. The presence of abundant surface basic sites and a larger amount of oxygen vacancies also facilitated the catalytic efficiency of Co 3 O 4 /eggshell-DP. [Display omitted] [ABSTRACT FROM AUTHOR]