Fig. 14. Morphology of diverse metal oxide@lignin NPs: (a) SEM image of magnetic lignin spheres having Fe₃O₄ NPs attached on the smooth surface (yellow circle) and into surface holes (green circle). Reproduced with permission from ref. 295; (b) TEM image depicting the sunflower morphology of magnetic lignosulfonate NPs comprising Fe₃O₄. Reproduced with permission from ref. 296; (c) TEM image of Fe₂O₃@lignosulfonate@polystyrene composite latex particles prepared by Pickering miniemulsion polymerization. Reproduced with permission of Elsevier from ref. 301; (d) HRTEM image on an individual Fe₃O₄@lignin NP. Reproduced with permission from ref. 303 and (e) HRTEM image showing the lignin coating onto a Cu₂O NP. The lattice spacing is about 0.24 nm, in agreement with the crystal lattice theoretical for the (111) plane of Cu₂O. Reproduced with permission from ref. 305.