Synthesis of alkoxyphenols-rich bio-oil by microwave-assisted catalytic pyrolysis of wood over MoS2 catalyst

Microwave-assisted pyrolysis (MAP) is widely concerned as a high-efficiency treatment of forestry solid waste to produce value-added products. In this study, alkoxyphenols-rich bio-oil was selectively produced from wood powder through MAP process using self-made MoS2 catalysts. First of all, the yield of bio-oil was selectively controlled by changing the process parameters of microwave power, temperature and catalyst weight content. Under the conditions of 1200 W, 600 °C and 10 wt% of catalyst to feedstock, an optimal bio-oil yield of 54.3 wt% was achieved over the MoS2 catalysts. Notably, compared with commercial MoS2-catalyzed and non-catalyzed MAP, the self-made MoS2-catalyzed process realized the improvement for the content of both general phenol species and specific alkoxyphenols component, reaching up to 90.1 % and 77.3 %, respectively at 1200 W, 600 °C and 10 wt% of catalyst to feedstock, which was superior to most of the previously reported candidates. The contrast experiment evidenced the bifunctional roles of MoS2 as both microwave absorbent and catalyst. It could not only promote the production of bio-oil but also inhibit the carbonization, selectively upgrade non-condensable gas to bio-oil, and simultaneously limit the second pyrolysis of alkoxyphenols, which jointly leads to the efficient synthesis of alkoxyphenols-rich bio-oil. This work provides guidance for producing phenols-rich bio-oil and other highly value-added products through the microwave-assisted catalytic pyrolysis of biomass over transition metal dichalcogenides materials.