Advanced fabrication of lignin-formaldehyde resin derived carbon microspheres via spray drying

Carbon hollow microspheres (CHM) have been heralded as a seminal material, manifesting a multifaceted utility in domains such as catalysis, adsorption, energy storage, and conversion. In this study, the present investigation delves into the fabrication of lignin-formaldehyde resin (LFR) carbon hollow microspheres (LFR-CHM) via the nuanced methodologies of spray drying and subsequent carbonization . The precursor for CHM, a thermosetting LFR, was crafted via polycondensation in an alkaline milieu. Precision-tuning of the spray drying parameters enabled the realization of LFR hollow microspheres, characterized by particle diameters spanning 3.37 μm–24.4 μm, and shell thickness between 0.25 μm and 4.0 μm. Adjusting the inlet temperature from 110 to 180 °C resulted in LFR hollow microspheres with varying bulk densities from 0.31 g/cm 3 to 0.49 g/cm 3 . The microporous structure of the LFR-CHM shell exhibited a malleable specific area and pore dimensionality, intricately tethered to the carbonization thermal gradient . Furthermore, changes in crystallinity and chemical bonds of LFR-CHM were noted during carbonization process. Significantly, the residual weight of LFR-CHM reached 52 % after carbonization at 800 °C, underscoring the benefits of using thermosetting lignin-formaldehyde resin as a CHM precursor.