Biomass waste conversion into low-cost carbon-based materials for supercapacitors: A sustainable approach for the energy scenario

Abstract

Biomass upgrading is a promising approach to face the current energy consumption and chemicals production. Lignocellulosic biomass residues have taken the lead in this field. In this study, hemp residue-based activated carbons (ACs) were prepared by H3PO4-assisted hydrothermal carbonization (HTC) using a low concentration of H3PO4 (25 wt. %). ACs with a high porosity development were obtained (SBET>1200 m 2 g-1), and they were subsequently functionalized with nitrogen groups using mild conditions. As-synthesized ACs were also heat-treated to enhance the electrical conductivity, improving the electrochemical performance. As a proof of concept, electrochemical capacitors (ECs) based on as-prepared ACs in aqueous and organic electrolytes, showing energy densities comparable to those of a capacitor based on an AC used in commercial capacitors. The most attractive outcome of this study is the straightforward, cost-effective, and sustainable methodology to prepare high added-value functional ACs with great potential for energy and environmental applications.

H2 Production from Formic Acid Using Highly Stable Carbon-Supported Pd-Based Catalysts Derived from Soft-Biomass Residues: Effect of Heat Treatment and Functionalization of the Carbon Support

“…After functionalization (N-BC), a significant decrease in the evolution of CO was observed at high temperatures, which indicates that during the functionalization reaction phenol and carbonyl groups are consumed, confirming that the generation of nitrogen groups occurs through substitution reactions with these oxygen groups [ 35 , 50 ].…”

“…The starting carbon support was synthesized by H 3 PO 4 -assisted hydrothermal carbonization using a soft-biomass waste following the procedure described elsewhere [ 35 ]. The as-prepared carbon support was named BC.…”

“…The resulting heat-treated carbon was denoted as BC_TT. (ii) Modification of the surface chemistry by incorporating nitrogen functional groups using a protocol described elsewhere [ 35 ]. The N-containing support was denoted as N-BC.…”

Biomass Based Materials in Electrochemical Supercapacitor Applications

“…The addition of heteroatoms provides interconnected networks between pores. Chaparro-Garnica et al [54] synthesized highly porous (SBET >1200 m 2 g −1 ) activated carbon from hemp residue by H 3 PO 4 -assisted hydrothermal carbonization (HTC). Then they doped the obtained activated carbon with nitrogen groups and stabilized the Table 1.…”

Synthesis Methods and Applications of Semiconductor Material ZnWO4 with Multifunctions and Multiconstructions

“…At present, the capacitance performance of carbon‐based electrode materials is improved by increasing the specific surface area of electrode materials and preparing mesoporous carbon electrode materials. [ 17–20 ] The excellent performance of tungstate materials in electron transport and redox couple also makes them attract much attention in the field of supercapacitors. Kumar et al [ 21 ] hydrothermally synthesized ferrous tungstate and functionalized multiwalled carbon nanotubes (FeO 4 W/f‐MWCNTs) for a novel nanocomposite electrode for high‐performance supercapacitors, which significantly improved the charging time, specific power, and cycle life.…”