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15 pages, 2863 KiB

Open AccessArticle

Tailoring Electrocatalytic Properties of sp²-Bonded Carbon Nanoforms Through Doping

by Paweł Szroeder, Agnieszka Banaszak-Piechowska and Ihor Sahalianov

Molecules 2025, 30(6), 1265; https://doi.org/10.3390/molecules30061265 - 12 Mar 2025

Viewed by 533

Abstract

The symmetry of the valence and conduction bands in graphene and carbon nanotubes allows for easy modification of the electronic structure, which is correlated with their electrocatalytic activity. Modifying the electronic structure of the sp²-bonded nanocarbons by substituting carbon atoms with [...] Read more.

The symmetry of the valence and conduction bands in graphene and carbon nanotubes allows for easy modification of the electronic structure, which is correlated with their electrocatalytic activity. Modifying the electronic structure of the sp²-bonded nanocarbons by substituting carbon atoms with electron donors/acceptors and through covalent functionalization can facilitate heterogeneous electron transfer (HET), which is beneficial for designing carbon-based, high-performance electrocatalysts. Based on the Gerischer–Marcus model, we discuss how we can match the density of π-electron states (DOS) of a nanocarbon electrode to the redox potential of redox species using electron and hole doping. Along with the results, this article provides guidance on how to match the properties of nanocarbons to specific electroactive analytes, oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), and oxygen evolution reaction (OER). Full article

(This article belongs to the Special Issue Carbon-Based Electrochemical Materials for Energy Storage)

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11 pages, 10826 KiB

Open AccessArticle

Lignin-Derived Activated Carbon as Electrode Material for High-Performance Supercapacitor

by Chenghao Pan, Yongfeng Ji, Suxia Ren, Tingzhou Lei and Lili Dong

Molecules 2025, 30(1), 89; https://doi.org/10.3390/molecules30010089 - 29 Dec 2024

Cited by 1 | Viewed by 919 | Correction

Abstract

Utilizing lignin-derived activated carbon in supercapacitors has emerged as a promising approach to alleviating environmental pollution and promoting the high-value utilization of byproducts in the papermaking industry. In this study, activated carbons (LACs) were prepared using a simple one-step KOH activation approach and [...] Read more.

Utilizing lignin-derived activated carbon in supercapacitors has emerged as a promising approach to alleviating environmental pollution and promoting the high-value utilization of byproducts in the papermaking industry. In this study, activated carbons (LACs) were prepared using a simple one-step KOH activation approach and by employing enzymatic hydrolysis lignin (EHL). The impact of the KOH activation parameters on the microstructure and capacitive performance of the LACs was investigated by varying the KOH/EHL ratio and activation temperature. The optimized sample LAC_800-4 showed an interconnected porous structure with a high surface area of 2285 m²/g, abundant micropores, and a small number of mesopores, which makes it a suitable electrode material for supercapacitors. The sample LAC_800-4 demonstrated a high specific capacitance of 291.3 F/g in a three-electrode system. Under a symmetrical supercapacitor electrode system, the specific capacitance of the LAC_800-4 electrode reached 186.8 F/g at 0.5 A/g. After 10,000 cycles at 20 A/g, the capacitance retention rate remained at 96.1%. The symmetrical supercapacitor also demonstrated a superior energy density of 6.5 Wh/kg. This work provides valuable insights into the transformation of low-value natural biomass derivatives into environmentally friendly, high-performing supercapacitor electrode materials. Full article

(This article belongs to the Special Issue Carbon-Based Electrochemical Materials for Energy Storage)

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10 pages, 2377 KiB

Open AccessArticle

Roughing Nitrogen-Doped Carbon Nanosheets for Loading of Monatomic Fe and Electroreduction of CO₂ to CO

by Yuxuan Liu, Yufan Tan, Keyi Zhang, Tianqi Guo, Yao Zhu, Ting Cao, Haiyang Lv, Junpeng Zhu, Ze Gao, Su Zhang, Zheng Liu and Juzhe Liu

Molecules 2024, 29(23), 5561; https://doi.org/10.3390/molecules29235561 - 25 Nov 2024

Viewed by 871

Abstract

The catalyst is the pivotal component in CO₂ electroreduction systems for converting CO₂ into valuable products. Carbon-based single-atom materials (CSAMs) have emerged as promising catalyst candidates due to their low cost and high atomic utilization efficiency. The rational design of the [...] Read more.

The catalyst is the pivotal component in CO₂ electroreduction systems for converting CO₂ into valuable products. Carbon-based single-atom materials (CSAMs) have emerged as promising catalyst candidates due to their low cost and high atomic utilization efficiency. The rational design of the morphology and microstructure of such materials is desirable but poses a challenge. Here, we employed different Mg(OH)₂ templates to guide the fabrication of two kinds of amorphous nitrogen-doped carbon nanosheet-supported Fe single atoms (FeSNC) with rough and flat surface structures. In comparison to flat FeSNC with saturated FeN₄ sites, the rough FeSNC (R-FeSNC) exhibited unsaturated FeN_4−x sites and contracted Fe-N bond length. The featured structure endowed R-FeSNC with superior capacity of catalyzing CO₂ reduction reaction, achieving an exceptional CO selectivity with Faradaic efficiency of 93% at a potential of −0.66 V vs. RHE. This study offers valuable insights into the design of CSAMs and provides a perspective for gaining a deeper understanding of their activity origins. Full article

(This article belongs to the Special Issue Carbon-Based Electrochemical Materials for Energy Storage)

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13 pages, 3472 KiB

Open AccessArticle

Fabrication of Pb-Containing PtAu Nanoflowers via Galvanic Replacement Method for Electrocatalytical Oxidation of Methanol

by Zhao Huang, Zhirou Zhang, Long Chao and Xueen Jia

Molecules 2024, 29(23), 5492; https://doi.org/10.3390/molecules29235492 - 21 Nov 2024

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Abstract

A Pb-containing PtAu nanoflower electrocatalyst was deposited on the cathode via galvanic replacement reaction in a double-cabin galvanic cell (DCGC) with a Cu plate as the anode, a multiwalled carbon nanotube (MWCNT) modified glassy carbon electrode (GCE) as the cathode, 0.1 M HClO [...] Read more.

A Pb-containing PtAu nanoflower electrocatalyst was deposited on the cathode via galvanic replacement reaction in a double-cabin galvanic cell (DCGC) with a Cu plate as the anode, a multiwalled carbon nanotube (MWCNT) modified glassy carbon electrode (GCE) as the cathode, 0.1 M HClO₄ aqueous solution as the anolyte, and Pb²⁺-containing Pt⁴⁺ salt and Au³⁺ salt mixed aqueous solution as the catholyte, respectively, and the electrocatalytic performance of the modified electrode toward methanol oxidation in the alkaline medium was investigated. Electrochemical studies reveal that the stripping of bulk Cu can induce underpotential deposition (UPD) of Pb on Pt during the galvanic replacement reaction, which affects the morphology and composition of Pb-containing PtAu nanoparticles. Under the optimal experimental conditions, a Pb-Pt₃Au₁/MWCNTs/GCE shows the highest activity and the best stability toward electrocatalytic oxidation of methanol in the alkaline medium, and the Pt active area-normalized specific electrocatalytic activity of Pb-Pt₃Au₁/MWCNTs/GCE is as high as 59.8 mA cm_Pt⁻². We believe that the method presented here of depositing highly active noble metal nanostructures by galvanic replacement reaction in a DCGC device is expected to be widely applied in the preparation of nanomaterials for their study in fuel cells and electrocatalysis. Full article

(This article belongs to the Special Issue Carbon-Based Electrochemical Materials for Energy Storage)

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18 pages, 7285 KiB

Open AccessArticle

A Strategy for Anode Recovery and Upgrading by In Situ Growth of Iron-Based Oxides on Microwave-Puffed Graphite

by Wenxin Chen, Jing Sun, Pingshan Jia, Wenlong Wang, Zhanlong Song, Ziliang Wang, Xiqiang Zhao and Yanpeng Mao

Molecules 2024, 29(13), 3219; https://doi.org/10.3390/molecules29133219 - 7 Jul 2024

Cited by 1 | Viewed by 1322

Abstract

Faced with the increasing volume of retired lithium-ion batteries (LIBs), recycling and reusing the spent graphite (SG) is of great significance for resource sustainability. Here, a facile method for transforming the SG into a carbon framework as well as loading Fe₂O [...] Read more.

Faced with the increasing volume of retired lithium-ion batteries (LIBs), recycling and reusing the spent graphite (SG) is of great significance for resource sustainability. Here, a facile method for transforming the SG into a carbon framework as well as loading Fe₂O₃ to form a composite anode with a sandwich structure is proposed. Taking advantage of the fact that the layer spacing of the spent graphite naturally expands, impurities and intercalants are eliminated through microwave thermal shock to produce microwave-puffed graphite (MPG) with a distinct three-dimensional structure. Based on the mechanism of microwave-induced gasification intercalation, a Fe₂O₃-MPG intercalation compound (Fe₂O₃-MPGIC) anode material was constructed by introducing iron precursors between the framework layers and subsequently converting them into Fe₂O₃ through annealing. The Fe₂O₃-MPGIC anode exhibits a high reversible capacity of 1000.6 mAh g⁻¹ at 200 mA g⁻¹ after 100 cycles and a good cycling stability of 504.4 mAh g⁻¹ at 2000 mA g⁻¹ after 500 cycles. This work can provide a reference for the feasible recycling of SG and development of high-performance anode materials for LIBs. Full article

(This article belongs to the Special Issue Carbon-Based Electrochemical Materials for Energy Storage)

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14 pages, 8743 KiB

Open AccessArticle

An Electrochemical Immunosensor Based on Chitosan–Graphene Nanosheets for Aflatoxin B1 Detection in Corn

by Shuai Zhang, Caizhang Wu, Zhike Zhao and Kun Xu

Molecules 2024, 29(7), 1461; https://doi.org/10.3390/molecules29071461 - 25 Mar 2024

Cited by 6 | Viewed by 1564

Abstract

We reported a highly efficient electrochemical immunosensor utilizing chitosan–graphene nanosheets (CS-GNs) nanocomposites for the detection of aflatoxin B₁ (AFB₁) in corn samples. The CS-GNs nanocomposites, serving as a modifying layer, provide a significant specific surface area and biocompatibility, thereby enhancing [...] Read more.

We reported a highly efficient electrochemical immunosensor utilizing chitosan–graphene nanosheets (CS-GNs) nanocomposites for the detection of aflatoxin B₁ (AFB₁) in corn samples. The CS-GNs nanocomposites, serving as a modifying layer, provide a significant specific surface area and biocompatibility, thereby enhancing both the electron transfer rate and the efficiency of antibody immobilization. The electrochemical characterization was conducted utilizing both differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Moreover, the antibody concentration, pH, antibody immobilization time, and immunoreaction time, were optimized. The results showed that the current change (

Δ I

) before and after the immunoreaction demonstrated a strong linear relationship (

R^{2} = 0.990

) with the AFB₁ concentration, as well as good specificity and stability. The linear range extended from 0.05 to 25 ng/mL, with a detection limit of 0.021 ng/mL (

S / N = 3

). The immunosensor exhibited a recovery rate ranging from 97.3% to 101.4% in corn samples, showing a promising performance using an efficient method, and indicating a remarkable prospect for the detection of fungal toxins in grains. Full article

(This article belongs to the Special Issue Carbon-Based Electrochemical Materials for Energy Storage)

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14 pages, 5584 KiB

Open AccessArticle

Interfacial Interaction in NiFe LDH/NiS₂/VS₂ for Enhanced Electrocatalytic Water Splitting

by Tingxia Wang, Xu Zhang, Xiaojiao Yu, Junpeng Li, Kai Wang and Jinfen Niu

Molecules 2024, 29(5), 951; https://doi.org/10.3390/molecules29050951 - 21 Feb 2024

Cited by 4 | Viewed by 1995

Abstract

A bifunctional electrocatalyst with high efficiency and low costs for overall water splitting is critical to achieving a green hydrogen economy and coping with the energy crisis. However, developing robust electrocatalysts still faces huge challenges, owing to unsatisfactory electron transfer and inherent activity. [...] Read more.

A bifunctional electrocatalyst with high efficiency and low costs for overall water splitting is critical to achieving a green hydrogen economy and coping with the energy crisis. However, developing robust electrocatalysts still faces huge challenges, owing to unsatisfactory electron transfer and inherent activity. Herein, NiFe LDH/NiS₂/VS₂ heterojunctions have been designed as freestanding bifunctional electrocatalysts to split water, exhibiting enhanced electron transfer and abundant catalytic sites. The optimum NiFe LDH/NiS₂/VS₂ electrocatalyst exhibits a small overpotential of 380 mV at 10 mA cm⁻² for overall water splitting and superior electrocatalytic performance in both hydrogen and oxygen evolution reactions (HER/OER). Specifically, the electrocatalyst requires overpotentials of 76 and 286 mV at 10 mA cm⁻² for HER and OER, respectively, in alkaline electrolytes, which originate from the synergistic interaction among the facilitated electron transfer and increasingly exposed active sites due to the modulation of interfaces and construction of heterojunctions. Full article

(This article belongs to the Special Issue Carbon-Based Electrochemical Materials for Energy Storage)

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27 pages, 7392 KiB

Open AccessReview

Pore Engineering in Biomass-Derived Carbon Materials for Enhanced Energy, Catalysis, and Environmental Applications

by Qi Wang, Bolong Luo, Zhaoyu Wang, Yao Hu and Mingliang Du

Molecules 2024, 29(21), 5172; https://doi.org/10.3390/molecules29215172 - 31 Oct 2024

Cited by 6 | Viewed by 1644

Abstract

Biomass-derived carbon materials (BDCs) are highly regarded for their renewability, environmental friendliness, and broad potential for application. A significant advantage of these materials lies in the high degree of customization of their physical and chemical properties, especially in terms of pore structure. Pore [...] Read more.

Biomass-derived carbon materials (BDCs) are highly regarded for their renewability, environmental friendliness, and broad potential for application. A significant advantage of these materials lies in the high degree of customization of their physical and chemical properties, especially in terms of pore structure. Pore engineering is a key strategy to enhance the performance of BDCs in critical areas, such as energy storage, catalysis, and environmental remediation. This review focuses on pore engineering, exploring the definition, classification, and adjustment techniques of pore structures, as well as how these factors affect the application performance of BDCs in energy, catalysis, and environmental remediation. Our aim is to provide a solid theoretical foundation and practical guidance for the pore engineering of BDCs to facilitate the rapid transition of these materials from the laboratory to industrial applications. Full article

(This article belongs to the Special Issue Carbon-Based Electrochemical Materials for Energy Storage)

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