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Ethyl acetate, a typical oxygen-containing volatile organic compounds (OVOCs) pollutant with a pungent odor and low toxicity, is still a great challenge to catalyze degradation at room temperature. Here, nitrogen-doped activated carbon loading Ni monolithic catalysts prepared by the one-pot impregnation method at an annealing temperature of 900°C (Ni/NAC-900) achieves the 95 % removal of ethyl acetate and 67.15 % CO 2 selectivity within 58.5 h at 25°C. The result of XRD proves the monolithic catalysts contains Ni single atoms and Ni NPs, of which the Ni single atoms accounts for 92 % of the total Ni elements. The XAFs characterization results shows that the active site structure of Ni single atoms is NiN 4 C 2 coordination structure. Hydroxyl radicals (·OH) converted by O 2 and H 2 O in the air on the atomically dispersed NiN 4 C 2 catalytic centers results in the breakage of the C-O bond and C-C bond, which eventually causes the oxidation of ethyl acetate to CO 2 and H 2 O. The findings provide fresh insights into the degradation of ethyl acetate with high efficiency, low consumption and in a safe manner. [Display omitted] • A atomically dispersed Ni monolithic catalyst achieved 100 % removal of ethyl acetate under mild conditions of 101.3 kPa and 25 ℃. • The catalyst generated oxygen vacancies that activated hydroxyl radicals (·OH). • The NiN4C2 structure served as the active site structure of Ni single atoms. • The N element greatly promoted the uniform dispersion of Ni and better electron transfer on the surface of AC carrier. [ABSTRACT FROM AUTHOR]

Normal temperature catalytic ozonation is an effective method for the removal of volatile organic compounds (VOCs). A series of TiO2-supported noble metal catalysts were synthesized by a facile impregnation method. The as-prepared catalysts were evaluated for the catalytic oxidation of toluene. It was determined that the 1 wt%Pt/TiO2 exhibited outstanding performance that 65% conversion of toluene was achieved with the space velocity of 30,000 h−1 even at room temperature (25°C). The structure–activity relationship of various catalysts was investigated via BET, XRD, SEM, TEM as well as XPS. The results indicated that the uniform dispersion of Pt nanoparticles, abundant surface adsorbed oxygen species as well as the strong interaction between Pt and TiO2 favoured toluene degradation at normal temperature. Based on FT-IR, a simplified reaction scheme was proposed: toluene was first oxidized to benzoate species then alcohol species, ketones, carboxyl acids, which was finally degraded into CO2 and H2O. The low activation energy of 1 wt%Pt/TiO2 determined to be 47 kJ mol−1 also benefited for toluene degradation at ambient temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • Degradation of benzene over catalyst containing Pt single-atom at room temperature. • The catalyst contains of 78.11 % Pt-N 4 single atoms and 21.89 % Pt NPs. • High recycling capacity: benzene conversion decreased by only 1.9 % after 5 cycles. • Thorough degradation of benzene to CO 2 and H 2 O with 81.24 % CO 2 selectivity. The catalytic degradation of volatile organic compounds (VOCs) such as benzene via ring-opening at room temperature is challenging due to the presence of π-bonds in the ring-forming carbon atoms. This study involved the preparation of a novel Pt-loaded boron-carbon-nitride (Pt/BCN) catalyst containing single-atom active sites for efficient catalysis of benzene degradation at room temperature in air. The micromorphology, surface structure, and coordination environment of the catalyst were analyzed using characterization techniques including aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC–HAADF–STEM) and X-ray absorption fine structure (XAFS). The degradation mechanism was investigated using electron paramagnetic resonance (EPR) and in situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS). The experimental results demonstrate that Pt/BCN contains many Pt-N 4 single-atom active sites that can generate hydroxyl radicals under room-temperature air conditions, leading to the oxidation of benzene to CO 2 and H 2 O. Containing atomically dispersed active-site catalysts developed in this study offer a theoretical foundation for designing catalyst active centers in related fields and advancing the industrial application of room-temperature, low-carbon VOCs treatment technologies. [ABSTRACT FROM AUTHOR]

Benzene and its aromatic derivatives are typical volatile organic compounds for indoor and outdoor air pollution, harmful to human health and the environment. It has been considered extremely difficult to break down benzene rings at ambient conditions without external energy input, due to the extraordinary stability of the aromatic structure. Here, we show one such solution that can thoroughly degrade benzene to basically water and carbon dioxide at 25 °C in air using atomically dispersed Fe in N-doped porous carbon, with almost 100% benzene conversion. Further experimental studies combined with molecular simulations reveal the mechanism of this catalytic reaction. Hydroxyl radicals (·OH) evolved on the atomically dispersed FeN 4 O 2 catalytic centers were found responsible for initiating and completing the oxidation of benzene. This work provides a new chemistry to degrade aromatics at ambient conditions and also a pathway to generate active ·OH oxidant for generic remediation of organic pollutants. [Display omitted] • A single-atom Fe catalyst achieved complete degradation of benzene at 25 °C. • The catalyst activated air and produced hydroxyl radicals for benzene oxidation. • The Fe-N-O structure served as the catalytic center for hydroxyl radical generation. • The mechanism of radical generation and benzene oxidation were revealed by DFT. [ABSTRACT FROM AUTHOR]