Developing efficient, inexpensive, in situ tar reforming technologies under mild conditions is an important practical aspect of biomass gasification. In this study, a series of biochar-supported Ni catalysts (Ni/BC) were prepared via a simple one-step pyrolytic approach and first explored for steam reforming of toluene as a tar model compound at a relatively low temperature of 600 °C. The as-prepared catalysts can be directly used without a further reduction process. The abundant surface oxygen containing groups of the starting biomass and the high porosity of Ni/BC assisted with the dispersion of the Ni nanoparticles. The in situ generating process of metallic Ni nanoparticles via carbothermal reduction was manipulated to modulate the Ni particle size. A size-dependent behavior was observed, wherein 5Ni-600/BC (pyrolyzed at 600 °C, 5% Ni loading) with the smallest Ni particle size (4.2 nm) showed superior catalytic performance in terms of the initial intrinsic activity (turnover frequency value of 1.64 s −1 ) and stability over others, indicating the positive role of small particles with more corner and step sites, which was further proved by DFT calculations. In addition, 5Ni-600/BC was found to be effective in the steam reforming of real biomass tar by reducing both the tar amount and the molecular weight.

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The electron-rich nature of vinyl ethers (CH 2  CHOR) enables their versatile reactivity patterns with transition metal catalysts. Furthermore, they are highly attractive monomers for the synthesis of many polymers and copolymers. However, it is challenging to incorporate these substrates in transition metalcatalyzed olefin polymerization due to various side reactions such as cationic polymerization and β-OR elimination. The Brookharttype α-diimine palladium system can lead to the formation of branched (co)polymers with unique microstructures and potentially unique properties due to the characteristic chain-walking mechanism. Unfortunately, common vinyl ethers will induce cationic polymerization and catalyst decomposition for these catalysts. Within this context, the generation of ether-functionalized polyolefins with branched microstructures is attractive but remains a great challenge. In this study, we developed a system that combines palladium-catalyzed dimerization of vinyl ethers for the generation of β,γ-unsaturated acetals and palladium-catalyzed ethylene copolymerization with a dimerization product for the generation of polar functionalized branched polyolefins. The mechanism and catalyst optimization for the dimerization reaction were investigated in detail. This strategy combines catalytic organic synthesis and transition metal-mediated ethylene copolymerization to incorporate the abundant but challenging vinyl ether substrates into polyolefins. Importantly, the inserted acetal moiety can be readily converted to various functional groups through postpolymerization functionalization reactions, making this strategy even more versatile.

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Interactions between metals and oxide supports are crucial in determining catalytic activity, selectivity, and stability. For reducible oxide supported noble metals, a strong metal−support interaction (SMSI) has been widely recognized. Herein we report the intermediate selectivity and stability over an irreducible SiO 2 supported Pt catalyst in the hydrogenation of anthracene that are significantly boosted due to the SMSI-induced formation of intermetallic Pt silicide and Pt−SiO 2 interface. The limitation in the strong interaction between Pt nanoparticles and irreducible SiO 2 has been breached by combining the strong electrostatic adsorption method and following the high temperature reduction strategy. Due to the isolated Pt active sites by Si atoms, the activated H species produced over the Pt 2 Si/SiO 2 catalyst with an initial catalytic activity of 2.49 μmol/(m 2 /g)/h as well as TOF of 0.95 s −1 preferentially transfer to the outer ring of anthracene to 87% yield of symmetric octahydroanthracene (sym-OHA) by subsequent hydrogenation. In addition, the Pt 2 Si/SiO 2 catalyst presents an excellent stability after five cycles, which can be attributed to the fact that intermetallic Pt 2 Si nanoparticles are anchored firmly onto the surface of the SiO 2 support. The discovery contributes to broaden the horizons on the SMSI effect in the irreducible oxide supported metal particle catalysts and provides guidance to design the metal−SiO 2 interface and tune the surface chemical properties in diverse application conditions.