Tetrahedrally Crystallized Carbon from Biowaste-Derived Microcrystalline Cellulose

New carbon structures and allotropes could significantly contribute to material sustainability in an era of existential concerns. Herein, for the first time, a highly crystalline body-centered tetragonal (BCT) carbon structure was synthesized from a nonedible biowaste (coconut rachis) through a low-temperature carbonization process. The formation of BCT carbon was monitored via the crystal structure changes of the biowaste upon variation of the calcination temperature, showing the critical role of microcrystalline cellulose in achieving carbon allotropes with high crystallinity. The electronic properties of the synthesized carbon were also investigated, suggesting potential uses in applications such as photoconversion, photocatalysis, transistors, and sensors. This study opens the path toward the synthesis of new carbon allotropes sustainably for advanced applications.