Magnetically recyclable and remarkably efficient visible-light-driven photocatalytic hexavalent chromium removal based on plasmonic biochar/bismuth/ferroferric oxide heterojunction

Carbon spheres have been synthesized from larch residue via ultrasonic spray pyrolysis. The morphology and porous structure of the carbon spheres can be tailored by different precursors and soft template. The carbon spheres prepared with liquefied larch show honeycomb-like morphology with a size of 0.5–1 μm, while the carbon spheres prepared with liquefied larch-based resins exhibit smooth surface. Furthermore, the carbon spheres prepared with F127 exhibit well-developed mesoporosity with two-dimensional hexagonal structure of P6mm symmetry whereas the carbon spheres prepared in the absence of F127 show the disordered porous structure. The carbon spheres (CS-R-F) prepared with liquefied larch-based resins and F127 display a high specific capacitance of 231 F g−1 at a current density of 0.2 A g−1.