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

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-SiO2@C) layer via an evaporation-induced self-assembly and calcination procedure for toluene (tar model compound) steam reforming. The quality of the Ni-SiO2@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 SiO2 mesopores. A stable toluene conversion over 97% with an H-2 yield of 135 mu mol/min was obtained at 600 degrees 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. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

Steam reforming is an effective method for eliminating biomass tar and producing H-2-rich syngas. However, traditional Ni-based catalysts can easily deactivate due to mass transfer issues and catalyst bed clogging. A new approach using wood carbon (WC) with low-tortuosity microchannels and carbon-coated mesoporous nickel-silica nanocomposite (Ni-SiO2@C) has been developed for toluene steam reforming, resulting in improved mass transfer, coke resistance, and hydrothermal stability. The Ni-15SiO(2)@C/WC catalyst showed stable toluene conversion rates over 97% and H-2 yields of 135 mu mol/min at 600 degrees C, demonstrating high performance in tar reforming.