Unraveling the Unique Promotion Effects of a Triple Interface in Ni Catalysts for Methane Dry Reforming

Methane dry reforming (MDR) is of great interest for its efficient consumption of greenhouse gases and the production of valuable syngas. The interfaces of metal and boron nitride (BN) are expected to enhance the catalytic activity and inhibit coke formation. Herein, the composite of layered metal oxides (NiMgAlOx) and BN was constructed to form the interface-confined NiMgAlOx/BN (Ni-MAO/BN) catalysts, and the unique promotion effects of a triple interface in Ni catalysts were unraveled. The triple interface among the Ni, BN, and MgAlOx oxides enhances the sintering resistance of the developed catalysts, which endows the developed catalysts with excellent adsorption/activation capacity of CH4 and CO2 as well as superb stability during a long-term MDR activity test. The abundant bicarbonate (HCO3*) species in the Ni-MAO/BN catalysts demonstrates that the triple interface significantly enhances gas activation. Meanwhile, the dynamic variation of HCO3* and CO3* species further proves the inhibition of deep CH4 cracking and the fast reaction rate over the Ni-MAO/BN catalysts. The negligible graphitic carbon observed in the operando Raman spectra and the produced large amount of H2/CO demonstrate not only the excellent coke resistance but also the strengthened activation capability of CO2 and CH4. This work elucidates the role of interfacial effects on gas activation and provides innovative insights into the design of highly efficient Ni catalysts for MDR

Boosting Ozone Catalytic Oxidation of Toluene at Room Temperature by Using Hydroxyl-Mediated MnO_<i>x</i>/Al₂O₃ Catalysts

Ozone catalytic oxidation (OZCO) has gained great interest in environmental remediation while it still faces a big challenge during the deep degradation of refractory volatile organic compounds (VOCs) at room temperature. Hydroxylation of the catalytic surface provides a new strategy for regulating the catalytic activity to boost VOC degradation. Herein, OZCO of toluene at room temperature over hydroxyl-mediated MnOx/Al2O3 catalysts was originally demonstrated. Specifically, a novel hydroxyl-mediated MnOx/Al2O3 catalyst was developed via the in situ AlOOH reconstruction method and used for toluene OZCO. The toluene degradation performance of MnOx/Al2O3 was significantly superior to those of most of the state-of-the-art catalysts, and 100% toluene was removed with an excellent mineralization rate (82.3%) and catalytic stability during OZCO. ESR and in situ DRIFTs results demonstrated that surface hydroxyl groups (HGs) greatly improved the reactive oxygen species generation, thus dramatically accelerating the benzene ring breakage and deep mineralization. Furthermore, HGs provided anchoring sites for uniformly dispersing MnOx and greatly enhanced toluene adsorption and ozone activation. This work paves a way for deep decomposition of aromatic VOCs at room temperature