Nitrogen‐doping activated biomass carbon from tea seed shell for CO ₂ capture and supercapacitor

Abstract

Activated carbon is a promising material that has a broad application prospect.In this work, biomass (tea seed shell) was used to prepare activated carbon with KOH activation (referred to as AC), and nitrogen was doped in activated carbon using melamine as the nitrogen source (referred to as NAC-x, where x is the mass ratio of melamine and activated carbon). The obtained activated biomass carbon (activated bio-carbon) samples were characterized by Brunauer-Emmett-Teller (BET)-specific surface area analysis, ultimate analysis, X-ray photoelectron spectroscopy (XPS) analysis, Raman spectrum analysis, and X-ray diffraction (XRD) patterns. The specific surface areas of activated bio-carbons were 1503.20 m 2 /g (AC), 1064.54 m 2 /g (NAC-1), 1187.93 m 2 /g (NAC-2), 1055.32 m 2 /g (NAC-3), and 706.22 m 2 /g (NAC-4), revealing that nitrogen-doping process leads to decrease in specific surface area. XPS analysis revealed that the main nitrogen-containing functional groups were pyrrolic-N and pyridinic-N. The capacity of CO 2 capture and electrochemical performance of activated bio-carbon samples were investigated. The CO 2 capturing capacity followed this order: AC (3.15 mmol/g) > NAC-2 (2.75 mmol/g) > NAC-1 (2.69 mmol/g) > NAC-3 (2.44 mmol/g) > NAC-4 (1.95 mmol/g) at 298 K at 1 bar, which is consistent with the order of specific surface area. The specific surface area played a dominant role in CO 2 capturing capacity. As for supercapacitor, AC-4 showed the highest specific capacitance (168 F/g) at the current density of 0.5 A/g, but NAC-2 showed the best electrochemical performance (89 F/g) at 2 A/g. Nitrogen-containing functional groups and specific surface area both had an important impact on electrochemical performance. In general, NAC-3 and NAC-2 produced excellent electrochemical performance. Compared with NAC-3, less melamine was used to prepare NAC-2; therefore, NAC-2 was considered as the best activated bio-carbon for supercapacitor for 141 F/g (at 0.5 A/g), 108 F/g (at 1 A/g), and 89 F/g (at 2 A/g) in this work.

From basil seed to flexible supercapacitors: Green synthesis of heteroatom‐enriched porous carbon by self‐gelation strategy

“…The huge SSA, high microporosity, and moderate gravimetric specific capacitance (~200 F g −1 ) of activated carbons can be synthesized by carbonization of a carbon precursor and subsequent physical and/or chemical activation. Quan et al employed tea seed shell as carbon source to produce activated carbon with a SSA of 1503 m 2 g −1 and a capacitance of 168 F g −1 at 0.5 A g −1 by carbonization and KOH activation. KOH is by far the most popular porogen for porous carbon materials.…”

Preparation of activated biomass carbon from pine sawdust for supercapacitor and CO 2 capture

“…Their results suggest that the sample at 600°C have relatively high nitrogen content and performed a suitable CO 2 capture capacity of 4.4 mmol/g at 298 K under1 bar. Quan et al prepared N‐doped activated carbon by tea seed shell for CO 2 capture, the results concluded that the carbon materials has the highest CO 2 capture capacity of 3.15 mmol/g. Gao et al synthesized CaO‐based adsorbent for CO 2 capture and the CO 2 capture capacity up to 15.1 mmol/g and maintained great cyclic stability.…”

Highly porous honeycomb‐like activated carbon derived using cellulose pulp for symmetric supercapacitors

“…Rather than the biomass waste, solid waste can be a great option, as this approach could avoid the waste accumulation and also provide an effective alternative to commercialization 9,10 . Due to low cost, low generation of energy, and environmentally friendliness, these materials can be significant to reduce the dependency on high‐cost precursors 11,12 . Deriving activated carbon from the solid waste can be a solution to the combating global waste disposal issues 13,14 …”

“…9,10 Due to low cost, low generation of energy, and environmentally friendliness, these materials can be significant to reduce the dependency on high-cost precursors. 11,12 Deriving activated carbon from the solid waste can be a solution to the combating global waste disposal issues. 13,14 On the other hand, due to over dependency on the fossil fuels such as coal for energy demand, we are witnessing the more environmental-related issues such as increasing CO 2 concentration.…”