Hydropyrolysis of Residual Camellia sinensis and Its Cellulose and Lignin Fractions over Nickel Nanoparticles Confined Inside Carbon Nanotube Microreactors at Atmospheric Pressure

The potential of catalytic hydropyrolysis for the production of value-added chemicals from abundant residual biomass generated during the seasonal pruning of Camellia sinensis tea crops is evaluated. Nickel nanoparticles (similar to 7.2 nm) encapsulated inside the cavity of carbon nanotubes (CNTs) are prepared using an impregnation method and applied as microreactors in the catalytic hydropyrolysis of both fractionated and unfractionated biomass at atmospheric pressure. Over 86% of nanoparticles are selectively located inside the CNT channel with a Ni content of 13.4 wt % and a surface area of 129.3 m(2). g(-1). The influence of the catalyst/biomass ratio on the product yield and selectivity is examined, and the reaction pathways are discussed. Results reveal that the majority of oxygenated compounds are reformed into long-chain alkanes (50.5%) and aromatic hydrocarbons (33.0%) with a total oxygen content of 3.90% and a low heating value of 41.8 MJ.kg(-1), comparable to commercial fuels.

Automated summary

The potential of catalytic hydropyrolysis for producing value-added chemicals from residual biomass generated during seasonal pruning of tea plants has been evaluated. Nickel nanoparticles encapsulated in carbon nanotubes were found to be effective microreactors, with a high selectivity for long-chain alkanes and aromatic hydrocarbons, making them comparable to commercial fuels.