Figure S1. a) TGA of pecan nutshell with insert of DTA analysis and b) indexed diffractogram of pecan nutshell; Figure S2. a) IER-UNAM solar furnace configuration and main components: a concentrator made up of 409 hexagonal-shaped mirrors, an 81m² sun-tracking flat heliostat, that follows the sun in two axes and to redirect solar rays to the solar concentrator, a shutter between the heliostat and the concentrator that modulates the solar power incident on the concentrator, and therefore, controlling the temperature in the focal zone, and a surface capable of moving along all three axes where the reactor is placed b) Pyrolysis reactor, and c) pyrolysis rector viewed from solar concentrator; Figure S3. Temperature profiles of the experiments carried out at the IER-UNAM solar furnace; Figure S4. Nitrogen adsorption isotherms for carbons produced in a) solar furnace, and b) tube furnace. Pore diameter distribution of c) SF materials and d) TF materials; Figure S5. Main effects plot shows respectively the effect of temperature and concentration on the graphitization degree of the carbons obtained in the solar furnace (a and c) and the tube furnace (b and d); Figure S6. High-resolution XPS spectra of materials obtained in the solar furnace: a) C1s region, and b) O1s region; Figure S7. High-resolution XPS spectra of materials obtained in the tube furnace: a) C1s region, and b) O1s region; Figure S8. Raman spectra for a) SF materials and b) TF materials. PL spectra of c) SF materials and d) TF materials; Figure S9. a) Schematic of thermocouples placed on and within the alumina crucible. b) Picture of the alumina crucible setting for an experiment (shutter fully closed in the background); Figure S10. Microstructure and element distribution maps of material SF800-1R; S1. Activation and CaS formation: S1.1. Activation and formation of CaS: Figure S11. DSC (Top) and TGA (bottom) thermograms for thermal decomposition of (NH4)2SO3·H2O, and impregnated pecan nutshell with 1M and 3M (NH4)2SO3 solutions at a) 5 °C/min and b) 20 °C/min; Table S1. Main observations by DSC and comparison between (NH4)2SO3·H2O theoretical mass loss and experimentally mass loss observed by TGA; Equation S1; Equation S2; Equation S3; Equation S4; Equation S5.

O. Soto-Díaz, A. Ayala-Cortés, and D.R. Lobato-Peralta thank CONAHCYT for their master's and PhD scholarship support.

Under a Creative Commons BY-NC-ND 4.0 license.

Peer reviewed