Efficient catalysts of surface hydrophobic Cu-BTC with coordinatively unsaturated Cu(I) sites for the direct oxidation of methane.

Selective oxidation of methane to organic oxygenates over metal-organic frameworks (MOFs) catalysts at low temperature is a challenging topic in the field of C1 chemistry because of the inferior stability of MOFs. Modifying the surface of Cu-BTC via hydrophobic polydimethylsiloxane (PDMS) at 235 °C under vacuum not only can dramatically improve its catalytic cycle stability in a liquid phase but also generate coordinatively unsaturated Cu(I) sites, which significantly enhances the catalytic activity of Cu-BTC catalyst. The results of spectroscopy characterizations and theoretical calculation proved that the coordinatively unsaturated Cu(I) sites made H2O2 dissociative into •OH, which formed Cu(II)-O active species by combining with coordinatively unsaturated Cu(I) sites for activating the C-H bond of methane. The high productivity of C1 oxygenates (CH3OH and CH3OOH) of 10.67 mmol gcat.-1h-1 with super high selectivity of 99.6% to C1 oxygenates was achieved over Cu-BTC-P-235 catalyst, and the catalyst possessed excellent reusability.

Dendritic Mesoporous Silica Nanoparticle Supported PtSn Catalysts for Propane Dehydrogenation.

PtSn catalysts were synthesized by incipient-wetness impregnation using a dendritic mesoporous silica nanoparticle support. The catalysts were characterized by XRD, N2 adsorption-desorption, TEM, XPS and Raman, and their catalytic performance for propane dehydrogenation was tested. The influences of Pt/Sn ratios were investigated. Changing the Pt/Sn ratios influences the interaction between Pt and Sn. The catalyst with a Pt/Sn ratio of 1:2 possesses the highest interaction between Pt and Sn. The best catalytic performance was obtained for the Pt1Sn2/DMSN catalyst with an initial propane conversion of 34.9%. The good catalytic performance of this catalyst is ascribed to the small nanoparticle size of PtSn and the favorable chemical state and dispersion degree of Pt and Sn species.

Efficient Electrochemical Reduction of CO2 on g-C3 N4 Monolayer-supported Metal Trimer Catalysts: A DFT Study.

The electrochemical reduction of CO2 into valuable chemicals and fuels is a promising but challenging method to realize the carbon cycle. In this work, a series of transition metal trimer clusters supported on g-C3 N4 catalysts (M3 @g-C3 N4 , M=Cr, Mn, Fe, Co, Ni, Cu, and Ru) for electrochemical CO2 reduction (CO2 RR) toward C1 and C2 products were systemically studied using density functional theory (DFT) calculations. Our results show that CO2 could be adsorbed and activated effectively on M3 @g-C3 N4 from adsorption configurations and electronic structures analyses. Cu3 @g-C3 N4 is a promising electrocatalyst for CH4 production with a limiting potential of -0.42 V. Cr3 @g-C3 N4 , Fe3 @g-C3 N4 , and Co3 @g-C3 N4 produce a low limiting potential of -0.64 V, -0.45 V, and -0.64 V for C2 H4 production, respectively. Hydrogen evolution reaction is refrained on Cu3 @g-C3 N4 , Cr3 @g-C3 N4 , and Co3 @ g-C3 N4 . This work provides useful insights into transition metal trimer cluster catalysts with enhanced activity and selectivity in CO2 RR.