Synthesis, performance evaluation, and economic assessment of tailored Pt/TiO2 catalysts for selective biomass vapour upgrading via a scalable flame spray pyrolysis route

Abstract

Commercialization of next-generation nanostructured catalysts for biomass conversion is largely limited by the unique challenges associated with their large scale manufacture. In this work, we present the scalable, continuous synthesis of nanostructured Pt/TiO₂ catalysts in a single step via flame-spray pyrolysis (FSP) and demonstrate their utility in the upgrading of biomass vapours via catalytic fast pyrolysis (CFP). Spectroscopic and microscopic characterization of the catalysts prepared via FSP and conventional incipient wetness impregnation (IW) demonstrated that the FSP method enabled scalable production of Pt/TiO₂ with distinct Pt speciation (single atoms, clusters, and nanoparticles) that could be tuned by varying the Pt loading. This compositional control by FSP resulted in catalytic activity for upgrading of pine pyrolysis vapours to aromatics, oxygenates, and alkenes that was comparable to the IW analogues' performance, with the addition of more control over the product slate by modifying the FSP synthesis conditions. Specifically, the FSP-synthesized catalysts exhibited decreased hydrogenation performance and greater selectivity towards partially deoxygenated products, aromatics, (cyclo)alkanes, and (cyclo)alkenes with total hydrocarbon yields similar to IW-synthesized catalysts at equivalent Pt loadings. A preliminary cost analysis comparing the FSP and IW processes identified the major cost drivers, including solvent usage, process gas requirements, and Pt utilization, that can be addressed to improve the economic viability of the FSP synthesis developed herein.