The replacement of expensive metal powders in Ni(OH)₂-based cathodes is essential for reducing cost and environmental impact in aqueous Ni–Zn batteries. This work investigates graphitic wood-derived carbon (GWC) as a sustainable conductive additive to boost the performance of Ni(OH)₂ pasted electrodes prepared by a simple physical mixing process. A number of graphitic wood-derived carbon qualities are explored as functional additives replacing expensive cobalt and nickel powder additives while maintaining the electrochemical performance of Ni(OH)₂ electrodes in aqueous rechargeable Ni–Zn batteries. The GWC offers high electrical conductivity and a unique microsized particulate morphology. Optimizing the GWC content to 25 wt % yields a specific capacity of 284.2 mAh g^–1 at 0.2C, which is better than that of electrodes containing only Ni(OH)₂, with Ni/Co powders, or commercial carbon black. Furthermore, the open-circuit voltage hysteresis and state of charge are studied to understand the charge/discharge process, suggesting that GWC is an effective alternative to expensive metal powders, providing a low-cost and sustainable strategy for improving Ni(OH)₂-based electrodes through a straightforward manufacturing process.

Efficient and long-lasting electrocatalysts are one of the key factors in determining their large-scale commercial viability. Although the fundamentals of deactivation and regeneration of electrocatalysts are crucial for understanding and sustaining durable activity, little has been conducted on metalloids compared to metal-derived ones. Herein, by virtue of in situ seconds-resolved X-ray absorption spectroscopy, we discovered the chemical evolution during the deactivation-regeneration cycles of tellurium clusters supported by nitrogen-doped carbon (termed Te-ACs@NC) as a high-performance electrocatalyst in the hydrogen evolution reaction (HER). Through in situ electrochemical reduction, Te-ACs@NC, which had been deactivated due to surface phase transitions in a previous HER process, was reactivated and regenerated for the next run, where partially oxidized Te was found, surprisingly, to perform better than its nonoxidized state. After 10 consecutive deactivation-regeneration cycles over 480 h, the Te-ACs@NC retained 85% of its initial catalytic activity. Theoretical studies suggest that local oxidation modulates the electronic distribution within individual Te clusters to optimize the adsorption energy of water molecules and reduce dissociation energy. This study provides fundamental insights into the rarely explored metalloid cluster catalysts during deactivation and regeneration and will assist in the future design and development of supported catalysts with high activity and long durability.

A versatile 1,2,4-triazolium-based building unit has been developed for the synthesis of porous copolymer networks, which showed potential in CO₂ capture under low-pressure conditions and CO₂ conversion. The monomer (termed [APVT]Br.HBr) combined an amino and a 1,2,4-triazolium functional group in its chemical structure and was synthesized via a quaternization reaction of 1-vinyl-1,2,4-triazole with the 3-bromopropylamine hydrobromide salt. Porous copolymer networks were obtained via solvothermal radical copolymerization of [APVT]Br.HBr with divinylbenzene (DVB) followed by neutralization to deprotonate the amine. The influence of four types of counter-anions, that is, hydroxide (OH⁻), dicyanamide (DCA⁻), ethyl sulfate, and bis(trifluoromethanesulfonyl)imide (TFSI⁻), on CO₂ capture was investigated, where copolymers bearing DCA⁻ demonstrated superior performance. Finally, the aminated 1,2,4-triazolium bromide copolymer network was subjected to catalyze the addition of CO₂ to allyl glycidyl ether into the corresponding cyclic carbonate. Our results highlight the potential of porous 1,2,4-triazolium copolymers in CO₂ capture and their valorization.

In the past decade, there has been significant interest in heteroatom-doped porous carbons, driven by the distinctive and adjustable physical and chemical properties that they exhibit across scales, from the atomic to the macroscopic level. Particularly, attributes such as conductivity, electron density, high specific surface area, hierarchical pore structure, and oxidation resistance offer a wide range of characteristics for diverse applications. The development of multimodal, hierarchical pore sizes, ranging from micropores to macropores, ensures balanced diffusion resistance and a high surface area for active site accommodation. However, their synthesis usually involves multiple steps or complicated processing to incorporate both hierarchically porous structures and heteroatoms in carbon materials.

This PhD thesis explores poly(ionic liquid)s (PILs) for preparation of heteroatom-doped porous carbon materials, driven by the growing demand for functional carbons in industry and academia. The aim of this thesis is to develop straightforward synthetic approaches to introduce various heteroatoms and different pore sizes in the carbonous structure and study their diverse functions. Here, we propose and explore fabrication methods based on two precursors. First, PILs were examined as both the carbon and heteroatom source, serving as a sacrificial template for porous carbons. Second, the delicate structure of wood was employed as a carbon source to generate macropores, while being coated with PILs to introduce heteroatoms or iron-based nanoparticles and create additional micropores. Moreover, the application of these carbonaceous materials was studied in two areas, i.e., batteries and artificial enzymes. This research is likely to contribute to a deeper understanding of synthetic methodologies of heteroatom-doped porous carbon materials and their physiochemical properties for various applications.

Development of affordable, efficient and metal-free heterogeneous catalytic systems has been a persistent challenge in academia and industry. Heteroatom-doped metal-free carbon materials are increasingly recognized as valuable heterogeneous catalysts, and if well-designed, can present comparable performance to, or even surpass transition metal-containing catalysts. Their physicochemical properties and structural characteristics are tunable in a wide range, plus being free of leakage problems of transition metal species into the environment. Herein, three types of hierarchically porous N/X co-doped carbon materials (X denotes B, P or S) were synthesized via using poly(ionic liquid)s (PILs) as carbon precursors and source of heteroatom dopants. The incorporation of sacrificial pore-inducing templating agents which created abundant edge defects, in combination with a heteroatom co-doping strategy, enhanced the number of active sites and their peroxidase-like catalytic activities. Comparison with only nitrogen single-doped porous carbons as reference demonstrated that co-doping with nitrogen and another heteroatom exhibits higher peroxidase-like activity and affinity towards substrates. Among the three types of heteroatom co-doped porous carbonaceous artificial enzymes, the N/B co-doped carbonaceous catalyst displayed the highest specific activities and V_max values. These observations suggest a synergistic effect of the co-dopants, here N and B in the enzyme that holds a promising potential to further enhance peroxidase-like activity.

The pursuit of efficient and cost-effective metal-free heterogeneous catalytic systems remains a challenging task in materials research. Heteroatom-doped carbonaceous materials are increasingly recognized as powerful metal-free catalysts, often demonstrating catalytic performance comparable to or even surpassing metal-based alternatives. This is attributed to their tunable physicochemical properties, tailorable structural features, and environmentally friendly profile. In a straightforward single-step synthetic approach, we utilized wood as an eco-friendly and renewable carbon source, in conjunction with a poly(ionic liquid) as a heteroatom source and pore-making agent. The combination of both biobased and synthetic polymers in this method yielded sustainable, high-performance catalysts characterized by enhanced stability and reusability. The inclusion of sacrificial pore-inducing templates resulted in the formation of abundant defects serving as catalytically active sites, while codoping with boron and nitrogen further enhanced these sites, significantly impacting catalytic activities, as established by peroxidase-like activity in this study. The optimized codoped porous carbon membrane exhibited excellent peroxidase-type activity and catalyzed the oxidation reaction of 3,3′,5,5′-tetramethylbenzidine by hydrogen peroxide. This high activity was largely due to the dual heteroatom codoping effect and the mixed micro/macroporous structure of the membrane. Our work presents a versatile and eco-friendly method for fabricating hierarchically porous B/N codoped carbon membranes, offering a manageable, convenient, and recyclable biomimetic artificial enzyme with superior catalytic capabilities. This work introduces a practical and robust colorimetric method that can be used in healthcare and environmental rehabilitation.

Understanding the reconstruction of surface sites is crucial for gaining insights into the true active sites and catalytic mechanisms. While extensive research has been conducted on reconstruction behaviors of atomically dispersed metallic catalytic sites, limited attention has been paid to non-metallic ones despite their potential catalytic activity comparable or even superior to their noble-metal counterpart. Herein, we report a carbonaceous, atomically dispersed non-metallic selenium catalyst that displayed exceptional catalytic activity in the hydrazine oxidation reaction (HzOR) in alkaline media, outperforming the noble-metal Pt catalysts. In situ X-ray absorption spectroscopy (XAS) and Fourier transform infrared spectroscopy revealed that the pristine SeC₄ site pre-adsorbs an ∗OH ligand, followed by HzOR occurring on the other side of the OH–SeC₄. Theoretical calculations proposed that the pre-adsorbed ∗OH group pulls electrons from the Se site, resulting in a more positively charged Se and a higher polarity of Se–C bonds, thereby enhancing surface reactivity toward HzO/R.

Fe₃C nanoparticles hold promise as catalysts and nanozymes, but their low activity and complex preparation have hindered their use. Herein, this study presents a synthetic alternative toward efficient, durable, and recyclable, Fe₃C-nanoparticle-encapsulated nitrogen-doped hierarchically porous carbon membranes (Fe₃C/N–C). By employing a simple one-step synthetic method, we utilized wood as a renewable and environmentally friendly carbon precursor, coupled with poly(ionic liquids) as a nitrogen and iron source. This innovative strategy offers sustainable, high-performance catalysts with improved stability and reusability. The Fe₃C/N–C exhibits an outstanding peroxidase-like catalytic activity toward the oxidation of 3,3′,5,5′-tetramethylbenzidine in the presence of hydrogen peroxide, which stems from well-dispersed, small Fe₃C nanoparticles jointly with the structurally unique micro-/macroporous N–C membrane. Owing to the remarkable catalytic activity for mimicking peroxidase, an efficient and sensitive colorimetric method for detecting ascorbic acid over a broad concentration range with a low limit of detection (~2.64 µM), as well as superior selectivity, and anti-interference capability has been developed. This study offers a widely adaptable and sustainable way to synthesize an Fe₃C/N–C membrane as an easy-to-handle, convenient, and recoverable biomimetic enzyme with excellent catalytic performance, providing a convenient and sensitive colorimetric technique for potential applications in medicine, biosensing, and environmental fields.

High-frequency responsive capacitors with lightweight, flexibility, and miniaturization are among the most vital circuit components because they can be readily incorporated into various portable devices to smooth out the ripples for circuits. Electrode materials no doubt are at the heart of such devices. Despite tremendous efforts and recent advances, the development of flexible and scalable high-frequency responsive capacitor electrodes with superior performance remains a great challenge. Herein, a straightforward and technologically relevant method is reported to manufacture a carbon fabric membrane “glued” by nitrogen-doped nanoporous carbons produced through a polyelectrolyte complexation-induced phase separation strategy. The as-obtained flexible carbon fabric bearing a unique hierarchical porous structure, and high conductivity as well as robust mechanical properties, serves as the free-standing electrode materials of electrochemical capacitors. It delivers an ultrahigh specific areal capacitance of 2632 µF cm⁻² at 120 Hz with an excellent alternating current line filtering performance, fairly higher than the state-of-the-art commercial ones. Together, this system offers the potential electrode material to be scaled up for AC line-filtering capacitors at industrial levels. 

Herein, the fabrication of iron-containing porous polyelectrolyte membranes (PPMs) via ionic complexation between an imidazolium-based poly(ionic liquid) (PIL) and 1,1-ferrocenedicarboxylic acid is reported. The key parameters to control the microstructure of porous hybrid membranes are investigated in detail. Further aerobic pyrolysis of such porous hybrid membranes at 900 °C can transfer the ferrocene-containing PPMs into freestanding porous iron oxide films. This process points out a sacrificial template function of porous poly(ionic liquid) membranes in the fabrication of porous metal oxide films.