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[Display omitted] • Birnessite-type short rod-like MnO 2 (MnO 2 -SR) was prepared under ambient conditions. • MnO 2 -SR exhibits the highest activity with 90% of propane oxidized at 225 °C. • Oxygen vacancies and high valent Mn4+ species promote activating of O 2 and propane. • Dissociation of propane molecules is the decisive step in propane oxidation. Developing economical and robust noble metal-free materials for obstinate light alkane low-temperature decomposition is of great significance. Here, birnessite-type short rod-like MnO 2 was firstly prepared by facile mixing KMnO 4 and ascorbic acid under ambient conditions and employed in propane catalytic decomposition. Experimental results revealed that abundant oxygen vacancies and high valent Mn4+ species, superior reducibility, and high surface oxygen mobility guarantee the remarkable low-temperature activity of MnO 2 -SR, over which 90% of propane can be oxidized (T 90) at temperature as low as 225 °C, achieving a temperature reduction over 70 °C compared with that of δ-MnO 2 (T 90 = 300 °C) and α-MnO 2 (T 90 = 355 °C). In situ diffuse reflectance infrared Fourier transform spectroscopy revealed that the dissociation and activation of propane molecules is the decisive step in propane oxidation. Gaseous propane is slowly oxidized by adsorbed oxygen directly to the final mineralization products at low temperature region (<200 °C); at high temperature region (>200 °C) however, propane molecules are firstly dissociated and activated before oxidized to carbonate intermediate products over active oxygen, and then eventually oxidized to carbon dioxide and water. [ABSTRACT FROM AUTHOR]

[Display omitted] • Defects were introduced in MIL-125 to narrow the forbidden band width. • Improved the surface acidity of material for efficient degradation of mixed VOCs. • Revealed the catalytic mechanism using in situ DRIFTS spectroscopy and GC–MS. In this paper, the effect of three monocarboxylic acids on MIL-125 synthesis was systematically investigated and the results were discussed in detail. X-ray diffractometry (XRD) and nitrogen adsorption–desorption curves indicated that small molecule acids (acetic acid, propionic acid and butyric acid) affected the morphology of MIL-125 and induced lamellar pores and structural defects in the crystals. Thermogravimetric measurements confirmed the presence of acid-regulated defective metal–organic frameworks (MOFs). Electrochemical tests and density function theory calculations indicated that acid modulation could change the forbidden bandwidth of the material. The acid modification strategy effectively promoted the transfer of photogenerated electrons and enhanced the adsorption and activation of O 2 and H 2 O molecules, generating reactive radicals. The modified MOFs also showed excellent performance in the removal of mixed toluene and chlorobenzene. The degradation pathways of the mixture were analyzed by in situ infrared (IR) and gas chromatography-mass spectrometry (GC–MS). The mixture was converted to chlorophenolic intermediates in the presence of reactive oxygen species, further decomposed to form ethers and ethanol, and finally formed small molecules such as carbon dioxide and water. A feasible method was provided for the preparation of photocatalysts for the treatment of mixed VOCs. [ABSTRACT FROM AUTHOR]