Arming wood carbon with carbon-coated mesoporous nickel-silica nanolayer as monolithic composite catalyst for steam reforming of toluene.

Monolithic wood carbon armed with mesoporous nickel-silica nanocomposite layer is a stiff and highly efficient catalyst for toluene steam reforming. [Display omitted] • A thin Ni-silica layer was in-situ grown on the wall of wood carbon channels. • Small Ni nanoparticles are embedded in mesoporous silica with carbon protection. • The hardness and hydrothermal stability of monolithic wood carbon was improved. • The multilevel pore structure enhances mass transfer and avoids coke deposition. • The monolithic catalyst exhibits excellent tar steam reforming performance. Steam reforming is an effective measure for biomass tar elimination as well as H 2 -rich syngas (H 2 + CO) production. However, the granular or powdery Ni-based catalysts are prone to deactivation, which is caused by inappropriate mass transfer and clogging of catalyst bed. Herein, monolithic wood carbon (WC) with low-tortuosity microchannels is armed with a carbon-coated mesoporous nickel-silica nanocomposite (Ni-SiO 2 @C) layer via an evaporation-induced self-assembly and calcination procedure for toluene (tar model compound) steam reforming. The quality of the Ni-SiO 2 @C layer growing on the surface of WC microchannel is affected by the molar ratios of Si/Ni feed. A uniform thin-layer coverage is obtained on the Ni-15SiO 2 @C/WC (Si/Ni = 15) catalyst, where highly dispersed Ni nanoparticles (average size of 6.6 nm) with appropriate metal-support interaction and remarkable mechanical strength are achieved. The mass transfer, coke resistance, and hydrothermal stability of the Ni-15SiO 2 @C/WC catalyst were significantly improved by the multilevel structure assembled from the WC microchannels and the secondary ordered SiO 2 mesopores. A stable toluene conversion over 97% with an H 2 yield of 135 μmol/min was obtained at 600 °C on the Ni-15SiO 2 @C/WC catalyst. This work opens a new window for facilely constructing high-performance wood carbon-based monolithic tar reforming catalyst. [ABSTRACT FROM AUTHOR]