Design of biomass-based N, S co-doped porous carbon via a straightforward post-treatment strategy for enhanced CO2 capture performance

CH3COOK Etching to Prepare N-Doped Peanut Shell Microporous Carbon for Efficient CO2 Adsorption

This study successfully synthesized microporous nitrogen-doped biomass porous carbon (NPSCs) through a two-step method, utilizing cost-effective peanut shells as the carbon source, urea as the nitrogen source, and CH3COOK as the activating agent. By optimizing the ratio of the activating agent and the carbonization temperature, the pore structure and surface chemical properties of the NPSCs were effectively tailored. Characterization results revealed that the NPSCs exhibited a significant number of micropores, attributed to the critical etching effect of CH3COOK. The optimal sample, NPSC-2-700, demonstrated a specific surface area of 1455.41 m2/g and a micropore volume of 0.57 cm3/g. Notably, NPSC-2-700 achieved remarkable CO2 adsorption capacities of 3.91 and 5.90 mmol/g at 25 and 0 °C, respectively, under 1 bar. Additionally, NPSC-2-700 maintained exceptional adsorption performance even after ten consecutive CO2 adsorption-desorption cycles. The selectivity was calculated to be 43 using the ideal solution adsorption theory in a classic gas mixture (CO2/N2 = 15 vol %:85 vol %), demonstrating good dynamic CO2 capture capacity. These findings underscore the promising potential of nitrogen-doped microporous carbon materials for efficient carbon capture applications.

Hydrogen peroxide-treated glycerol sourced porous carbon with elemental sulfur-based sulfur-phosphorus co-doping for CO2 capture

In this work, glycerol and elemental sulfur-based porous carbon adsorbents with sulfur‑phosphorus co-doping and subsequent H2O2 treatment were developed for CO2 capture. The best adsorbent for capturing CO2 among the developed adsorbents was P‑carbon-2000mgS-H2O2, which had surface area of 652 m2/g, a total pore volume of 0.446 cm3/g, an average pore size of 2.74 nm, narrow micropore distribution, X-ray photoelectron spectroscopy (XPS)-based sulfur content of 5.7 at.% and phosphorus content of 3.7 at.%, Raman-based average PAHs size of 24.9 Å and a defect density of 4.47 × 1011 cm-2, and X-ray diffraction (XRD)-based nano-crystallite height of 11.15 Å and length of 23.35 Å. The CO2 adsorption capacity of P‑carbon-2000mgS-H2O2 was 1.95 mmol/g at 25 °C and 1 bar (3.02 mmol/g at 0 °C), and it also demonstrated an impressive CO2 selectivity over N2 at 25 °C, with 15.24 at 0.5 bar and 12.03 at 1 bar. In addition to cyclic performance, the isosteric heat of CO2 adsorption, which was found to be between 22 and 23 kJ/mol, suggested that a physical mechanism predominated the CO2 interaction with active sites. These findings suggest that employing elemental sulfur to produce glycerol-derived porous carbon with sulfur-phosphorus co-doping and subsequent H2O2 treatment is an effective method to produce CO2 capture adsorbents, facilitating the usage of glycerol and elemental sulfur - based products for large-scale applications.

Synergistic Coordination Effect and Metal-Support Interaction Engineering of Single-Atom Mn-N2 Sites for Boosting Sensitive and Selective Dopamine Biosensing in Human Serum

Coordination environment of metal atoms is core for designing high-performance single-atom catalysts (SACs), while metal-support interaction also has an important effect on structure-function relationship. Nevertheless, the interaction effect of metal-support is mostly ignored. Through synergistic regulation of coordination environment and metal-support interaction, Mn SAC with atom-dispersed Mn-N2 sites on dopamine (DA) support is synthesized for sensitive and selective DA oxidation based on theoretical calculations and experimental explorations. MnN2 presents the more optimal catalytic site for DA oxidation than other coordination conditions, enhancing sensitivity including a wide range, a low limit of detection, and particularly a very low catalytic potential. The construction of Mn-N2 active sites on DA carbon promotes the coupling between Mn metal atoms and DA support, decreasing work function, facilitating electron exchange, shortening response time, and boosting selectivity. Both the catalytic mechanism of Mn SAC toward DA and the relation construction of catalyst's structure and catalytic function are established.

Development and CO2 capture of nitrogen-enriched microporous carbon by coupling waste polyamides with lignocellulosic biomass

Due to the substantial emissions of global CO2, there has been growing interest in nitrogen-enriched porous carbonaceous materials that possess exceptional CO2 capture capabilities. In this study, a novel N-enriched microporous carbon was synthesized by integrating waste polyamides with lignocellulosic biomass, involving carbonization and physicochemical activation. As-synthesized adsorbents demonstrated significant characteristics including a high specific surface area (1710 m2/g) and a large micropore volume (0.497 cm3/g), as well as abundant N- and O-containing functional groups, achieved through activation at 700 °C. They displayed remarkable CO2 capture capability, achieving uptake levels of up to 6.71 mmol/g at 1 bar and 0 °C, primarily due to the filling effect of narrow micropore along with electrostatic interaction. Furthermore, the adsorbent exhibited a rapid capacity for CO2 capture, achieving 94.9% of its saturation capacity within a mere 5 min at 30 °C. This impressive performance was accurately described by the pseudo second-order dynamic model. Additionally, as-synthesized adsorbents displayed a moderate isosteric heat of CO2 adsorption, as well as superior selectivity over N2. Even after undergoing five consecutive cycles, it maintained ∼100% of its initial capacity. Undoubtedly, such findings hold immense significance in the mitigation of global plastic pollution and greenhouse effect.

Low temperature and facile synthesis of nitrogen-doped hierarchical porous carbon derived from waste polyethylene terephthalate for efficient CO2 capture

Waste polyethylene terephthalate (PET) with high carbon content (>60 wt%) has shown great potential in the field of synthesizing carbon materials for CO2 capture, attracting increasing attention. Herein, an innovative strategy was proposed to synthesize nitrogen-doped hierarchical porous carbon (PC) for CO2 capture using PET as precursor and sodium amide (NaNH2) as both nitrogen dopant and low-temperature activator. As-synthesized N-doped PC exhibited a significantly high micropore volume of 0.755 cm3/g and a rich content of N- and O-containing functional groups, offering ample active sites for CO2 molecules. Further, the adsorbents demonstrated excellent CO2 capture capacity, achieving 5.7 mmol/g (0 °C) and 3.3 mmol/g (25 °C) at 1 bar, respectively. This was primarily attributed to the synergistic effect of narrow micropores filling and electrostatic interactions. Moreover, as-synthesized PC exhibited rapid CO2 adsorption capability, and its dynamic adsorption process was effectively described using a pseudo-second-order kinetic model. After five consecutive cycles, PET-derived PC still maintained ~100 % of adsorption capacity. They also possessed good CO2/N2 selectivity and reasonable isosteric heat of adsorption. Therefore, as-synthesized nitrogen-doped PC is a promising CO2 adsorbent through low-temperature activation of carbonized PET with NaNH2. Such findings have substantial implications for waste plastic recycling and mitigating the greenhouse effect.