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Spectroscopic studies of the mechanistic steps that occur on supported precious metal catalysts used in industrial and automotive applications are hampered by a dearth of suitable experimental methods. We used femtosecond laser excitation followed by nanosecond time-resolved in situ Fourier-transform infrared spectroscopy to initiate a catalytic reaction on alumina-supported silver catalysts, which are of interest in minimizing nitrogen oxide emissions from fuel-efficient lean-burn engines. We found that the key intermediate step in the reaction between carbon monoxide and nitric oxide is the flip of a cyanide group from a silver nanoparticle to the alumina support (with a lifetime of 2 microseconds), which indicates the central role played by the interface between the metal particle and the oxide support.

Jump to it! 2D IR pressure‐jump spectroscopy of adsorbed CO can be used to assess the accessibility and location of platinum nanoparticles supported on a zeolite and investigate the behavior of Pt atoms after thermal treatment (activation, catalytic reaction, sintering). Different Pt nanoparticle sintering mechanisms were observed in the mesopores and on the external surface of the ZSM‐5 support (see picture; HF=high and LF=low frequency).

Continuous metal-organic framework-type Co(3)(HCOO)(6) intergrown films with a one-dimensional zigzag channel system and pore aperture of 5.5 Å are prepared by secondary growth on preseeded macroporous glass-frit disks and silicon wafers. The adsorption behavior of CO(2) or CH(4) single gases on the Co(3)(HCOO)(6) membrane is investigated by in situ IR spectroscopy. It is shown that the isosteric heats of adsorption for CO(2) (17.7 kJ mol(-1)) and CH(4) (14.4 kJ mol(-1)) do not vary with increasing amount of adsorbed gases. The higher value of isosteric heat for CO(2) is an indication of the stronger interaction between the CO(2) and the Co(3)(HCOO)(6) membrane. The Co(3)(HCOO)(6) membrane is studied by binary gas permeation of CO(2) and CH(4) at different temperatures (0, 25, and 60 °C). The membrane has CO(2)/CH(4) selectivity with a separation factor higher than 10, which is due to the unique structure and molecular sieving effect. Upon increasing the temperature from 0 to 60 °C, the preferred permeance of CO(2) over CH(4) is increased from 1.70×10(-6) to 2.09×10(-6) mol m(-2) s(-1) Pa(-1), while the separation factor for CO(2)/CH(4) shows a corresponding decrease from 15.95 to 10.37. The effective pore size of the Co(3)(HCOO)(6) material combined with the pore shape do not allow the two molecules to pass simultaneously, and once the CO(2) molecules are diffused in the micropores, the CH(4) is blocked. The supported Co(3)(HCOO)(6) membrane retains high mechanical stability after a number of thermal cycles.

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