Boosting N 2 O Decomposition by Fabricating the Cs-O-Co Structure over Co 3 O 4 with Single-Layer Atoms of Cs.

Developing effective catalysts for N2 O decomposition at low temperatures is challenging. Herein, the Cs-O-Co structure, as the active species fabricated by single-layer atoms of Cs over pure Co3 O4 , originally exhibited great catalytic activity of N2 O decomposition in simulated vehicle exhaust and flue gas from nitric acid plants. A similar catalytic performance was also observed for Na, K, and Rb alkali metals over Co3 O4 catalysts for N2 O decomposition, illustrating the prevalence of alkali-metal-promotion over Co3 O4 in practical applications. The catalytic results indicated that the TOF of Co3 O4 catalysts loaded by 4 wt% Cs was nearly 2 orders of magnitude higher than that of pure Co3 O4 catalysts at 300 °C. Interestingly, the conversions of N2 O decomposition over Co3 O4 catalysts doped by the same Cs loadings were significantly inhibited. Characterization results indicated that the primary active Cs-O-Co structure was formed by highly orbital hybridization between the Cs 6s and the O 2p orbital over the supported Co3 O4 catalysts, where Cs could donate electrons to Co3+ and produce much more Co2+ . In contrast, the doped Co3 O4 catalysts were dominated by Cs2 O2 species; meanwhile, CsOH species was generated by adsorbed water vapor led to a significant decrease in catalytic activity. In situ DRIFTS, rigorous kinetics, and DFT results elaborated the reaction mechanism of N2 O decomposition, where the direct decomposition of adsorbed N2 O was the kinetically relevant step over supported catalysts in the absence of O2 . Meanwhile, the assistance of adsorbed N2 O decomposition by activated oxygen was observed as the kinetically relevant step in the presence of O2 . The results may pave a promising path toward developing alkali-metal-promotion catalysts for efficient N2 O decomposition.