In this work, Mn-MOF-74 with hollow spherical structure and Co-MOF-74 with petal-like shape have been prepared successfully via the hydrothermal method. The catalysts were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry-mass spectrum analysis (TG-MS), N adsorption/desorption, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). It is found that MOF-74(Mn, Co) exhibits the capability for selective catalytic reduction (SCR) of NO at low temperatures. Both experimental (temperature-programmed desorption, TPD) and computational methods have shown that Co-MOF-74 and Mn-MOF-74 owned high adsorption and activation abilities for NO and NH. The catalytic activities of Mn-MOF-74 and Co-MOF-74 for low-temperature denitrification (deNO) in the presence of NH were 99% at 220 °C and 70% at 210 °C, respectively. It is found that the coordinatively unsaturated metal sites (CUSs) in M-MOF-74 (M = Mn and Co) played important roles in SCR reaction. M-MOF-74 (M = Mn and Co), especially Mn-MOF-74, showed excellent catalytic performance for low-temperature SCR. In addition, in the reaction process, NO conversion on Mn-MOF-74 decreased with the introduction of HO and SO and almost recovered when gas was cut off. However, for Co-MOF-74, SO almost has no effect on the catalytic activity. This work showed that MOF-74 could be used prospectively as deNO catalyst.

Direct ethanol fuel cell technology suffers from a lack of effective anode catalysts for complete ethanol oxidation reaction (EOR). Pd and Pd-based catalysts showed some promise, but only a trace amount of CO 2 was detected as the product. The difficulty of C−C bond cleavage and the formation of acetic acid are commonly believed to be great obstacles toward complete EOR. The limited formation of CO 2 also suggests that acetic acid may not be the only dead-end product that prevents complete EOR. A careful study on the reaction pathway leading to complete EOR is needed to better understand and design effective EOR catalysts. As such, we studied 17 key elementary reactions on Pd surfaces using density functional theory (DFT) and designed experiments to confirm some of the DFT findings. The results show that, in addition to the acetic acid formation, other poisonous species, C, CH, CCO, or dimerization of acetaldehyde, are also largely responsible for the limited formation of CO 2 on Pd catalysts due to their strong adsorptions to the catalysts which block the active sites. The ethanol oxidation shows totally different reaction pathways in neutral and alkaline media. The DFT calculation result provided important insights into the catalysis of complete ethanol oxidation. The experiment result showed that EOR on PdCu alloy nanoparticle catalyst has higher catalytic activity than that on Pd nanoparticle catalyst, suggesting fast kinetics of initial dehydrogenation on the alloy catalyst.

The novel Cu-MOF-74 materials were synthesized with various cosolvents at different temperatures by a solvent-thermal method and then developed as NO removal catalysts for low temperature selective catalytic reduction (SCR) with NH3. The physicochemical properties of catalyst samples were characterized by multiple techniques, such as N2 adsorption–desorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). The effects of cosolvent on the catalyst performances were systematically investigated. It was found that Cu-MOF-74-iso-80 catalyst showed the highest NH3-SCR activity, giving 97.8% NO conversion and 100% N2 selectivity at 230 °C. BET test results suggested that Cu-MOF-74 showed a larger specific surface area. Stronger NH3 adsorption ability was found, which could be beneficial for SCR at low temperature. The catalyst also showed better water resistance performance. The adverse effect of H2O added intermittently could be quickly eliminated when the water environment was removed.

Direct ethanol fuel cell technology is impeded by inefficient, yet expensive anode catalysts. As such, research on effective and cheap anode catalysts towards complete ethanol oxidation reaction (EOR) is greatly needed. Herein, we report the investigations of the competitive C-C and C-H bond scissions in the EOR involving CHCO, CHCO, and CHCO species on Cu(100) using density functional theory and transition state theory calculations. The easiest C-C bond cleavage was found in CHCO while the most difficult C-H bond cleavage was also found in CHCO, both with an activation energy of 1.02 eV. The feasible C-C bond scission may take place in CHCO with a rate constant ratio of the C-C to the C-H bond scission at 100 °C of 0.32. Furthermore, in an alkaline environment, the C-H bond scission activation barrier is considerably lowered but the C-C bond cleavage activation barrier is slightly increased for both CHCO and CHCO species. The reaction of CHCO species on Cu(100) under alkaline conditions produces mainly acetic acid with a barrier of 0.49 eV and a rate constant of 4.93 × 10 s at 100 °C.

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Deactivation study on the ethanol/acetaldehyde conversion to 1,3-butadiene over a ZnO–ZrO2–SiO2catalyst.

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