Quasi‐Isothermal Thermogravimetric Insight Into Energetic Heterogeneity of Ni‐Modified Biocarbons

Quasi‐isothermal thermogravimetric analysis (Q‐TG) was used to characterize the structure and energy heterogeneity of water layers adsorbed on the surface of nickel‐modified biocarbons. The investigated materials were obtained from biomass in the pyrolysis process carried out at temperatures of 500°C and 800°C, with the nickel contents of 5% and 10% by weight. The combination of Q‐TG, low‐temperature nitrogen adsorption, and FTIR, XRD, and XPS analyses enabled a comprehensive assessment of the effect of carbonization temperature and the presence of the metallic phase on porosity, surface chemistry, and water/biocarbon interactions. Biocarbons obtained at 500°C proved to possess a dominant microporosity and hydrophilic surface character, while carbonized materials at 800°C exhibit a micro‐/mesoporous structure, greater ordering of graphene domains, and increased hydrophobicity. The analysis of the relationship between and dG/dM derivatives revealed the presence of strong adsorption centers at a low degree of hydration and a shift in the capillary condensation threshold towards larger numbers of water monolayers with the increasing pyrolysis temperature and nickel content. The obtained results confirm the applicability of the Q‐TG method for the determination of energetic heterogeneity of biocarbons and indicate the possibility of controlling their hydrophilic/hydrophobic properties for environmental applications.