Publikační činnost Institutu environmentálních technologií / Publications of Centre for Environmental Technology (9350)

Permanent URI for this collectionhttp://hdl.handle.net/10084/64706

Kolekce obsahuje bibliografické záznamy publikační činnosti (článků) akademických pracovníků Institutu environmentálních technologií (9350) v časopisech registrovaných ve Web of Science od roku 2003 po současnost.
Do kolekce jsou zařazeny:
a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská-Technická univerzita Ostrava (VŠB-TUO),
b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

Bibliografické záznamy byly původně vytvořeny v kolekci Publikační činnost akademických pracovníků VŠB-TUO, která sleduje publikování akademických pracovníků od roku 1990.

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Now showing 1 - 20 out of 391 results

Ammonia and toluene oxidation: Mutual activating effect of copper and cerium on catalytic efficiency
(Elsevier, 2024) Górecka, Sylwia; Pacultová, Kateřina; Rokicińska, Anna; Górecki, Kamil; Kuśtrowski, Piotr; Obalová, Lucie
Copper and cerium containing hydrotalcite-like precursors Cux-Cey-Mg-Al were synthesized by mutual coprecipitation followed by calcination at 800 degrees C. The obtained mixed metal oxides were studied as catalysts for selective ammonia oxidation (NH 3 -SCO) and toluene combustion. Various techniques, such as temperatureprogrammed reduction with hydrogen, temperature -programmed desorption of toluene, scanning electron microscopy and reactive frontal chromatography were used to characterize the catalysts. Series 800-Cux-Ce2.5 showed the highest catalytic efficiency in both reactions, allowing complete NH 3 and C 7 H 8 conversion below 350 degrees C and 500 degrees C, respectively. CeO 2 crystallites (12-18 nm), as well as dispersed CuO oxide forms were found in the most active samples. Both phases affect pollutants conversion, however, for ammonia oxidation the occurrence of Cu 2+ is essential, while for toluene oxidation, the formation of Ce 4+ is sufficient. Over the most active sample (800-Cu5-Ce2.5) the complete conversion in mutual oxidation of NH 3 and toluene was achieved below 450 degrees C.
Enhancing biogas production amidst microplastic contamination in wastewater treatment systems: A strategic review
(MDPI, 2024) Otieno, Job Oliver; Cydzik-Kwiatkowska, Agnieszka; Jachimowicz, Piotr
This review highlights the significant interaction between microplastic (MP) pollution and its impact on wastewater treatment systems, focusing on optimizing biogas production. We explore various sources of MPs, including tire-derived MPs, and their introduction into wastewater environments. This review delves into the mechanical and physicochemical challenges MPs pose in treatment processes, emphasizing the need for comprehensive mitigation strategies. The biological effects of MPs on microbial consortia essential for biogas production are analyzed, particularly how these pollutants interfere with each stage of anaerobic digestion-hydrolysis, acidogenesis, acetogenesis, and methanogenesis-and, consequently, biogas generation. We examine MPs' quantitative and qualitative impacts on biogas output and production rates, uncovering how MPs disrupt microbial activity in these stages. This review also discusses novel mitigation strategies combining different sludge pretreatment methods with MPs. Our goal is to enhance the sustainability of wastewater management by promoting efficient biogas production and environmental protection in the presence of persistent MP contamination.
Evaluation of anisole hydrodeoxygenation reaction pathways over a Ni/Al2O3 catalyst
(Elsevier, 2024) Dutta, Snehasis; Shumeiko, Bogdan; Aubrecht, Jaroslav; Karásková, Kateřina; Fridrichová, Dagmar; Pacultová, Kateřina; Hlinčík, Tomáš; Kubička, David
Anisole is a model molecule for studying hydrodeoxygenation (HDO) of lignin -derived oxygenates. Here we elucidate its HDO pathway over 10 % Ni/Al2O3 catalyst. Adsorption experiments showed that anisole is adsorbed on the acidic sites of the Al2O3 . Anisole adsorption at 200 -300 degrees C is reactive in nature, and results in its demethylation. The catalyst was tested at 100 -300 degree celsius, 5 -40 bar H-2 pressure. Conversion of 78 % was obtained at 5 bar and 300 degrees C, restricted by hydrogenation -dehydrogenation equilibrium. HDO mainly starts through the ringhydrogenation pathway. This is followed by demethoxylation beyond 180 degree celsius. At 5 -12 bar, cyclohexane dehydrogenates to benzene. This was confirmed by conducting an HDO experiment with methoxycyclohexane. At lower pressure deoxygenation is favored; and demethylation is accompanied with methylation of the aromatic ring, for temperature >260 degree celsius Investigation of the initial reaction stages showed that anisole HDO on Ni/Al2O3 catalyst proceeds via two independent pathways i.e., reactive adsorption/(de)methylation and aromatic ring hydrogenation.
Photoreforming for microplastics recycling: A critical review
(Elsevier, 2024) Praus, Petr
Microplastics in the environment are a serious global problem for our society and there is a strong need to develop technologies for their removal and recycling. Photoreforming based on photocatalysis is a novel approach to convert microplastics to useful chemical compounds. In this work, the literature related to the photoreforming of microplastics was reviewed. The main product of the photoreforming was hydrogen obtained from polyethylene terephthalate (PET) and polylactic acid (PLA) with the highest yields of 113 mmol g- 1 h-1 and 95.6 mmol g- 1 h-1, respectively. The hydrogen yields were processed by the non-parametric Mann-Whitney, Kolmogorov-Smirnov, Moods median, and Kruskal-Wallis tests. The pre-treatment of microplastics before the photoreforming was not found to be a critical factor for the photoreforming. In addition, the photoreforming of PET and PLA was statistically proved to provide similar hydrogen yields. The selection of suitable photocatalysts was identified as the most important factor in the photoreforming process due to the effective separation of photoinduced electrons and holes. The reaction conditions should be optimized, especially in terms of the concentration of photocatalysts in the reaction suspensions of highly concentrated KOH or NaOH. The advantages of the photoreforming, such as reactions at ambient temperature and pressure, and the use of visible (solar) irradiation, are a challenge for further research mainly concerning the hydrogen production. More experimental data are necessary to evaluate and optimize some key parameters of this photoreforming process.
Metal-free hybrid nanocomposites of graphitic carbon nitride and char: Synthesis, characterisation and photocatalysis under visible irradiation
(Elsevier, 2024) Smýkalová, Aneta; Kinnertová, Eva; Slovák, Václav; Praus, Petr
Background The hybrid nanocomposites of graphitic carbon nitride (g-C3N4) and char were synthesised from melamine and hydroxyethyl cellulose/glucose to obtain metal-free photocatalysts active under visible irradiation. The nanocomposites were tested for the degradation of phenol and ofloxacin. Methods The nanocomposites were characterized by elemental and thermal analysis. Their electronic properties were studied by UV–Vis and photoluminescence spectroscopy. Texture and morphology were studied by physisorption of nitrogen, X-ray diffraction, infrared spectroscopy, X-ray photoelectron spectroscopy, and by transmission electron microscopy. The photocatalytic experiments were performed under the LED irradiation of 420 nm. Significant findings Hydroxyethyl cellulose and glucose formed char which was incorporated in the g-C3N4 structure. The char acted as an electron collector enabling the separation of photoinduced electrons and holes. In this way, the photocatalytic activity of g-C3N4 increased and 96% of ofloxacin was degraded during after 120 min. In addition, in this work the total combustion of graphitic carbon nitride up to 800 oC was investigated for the first time.
Tailoring the Li+ intercalation energy of carbon nanocage anodes via atomic Al-doping for high-performance lithium-ion batteries
(Wiley, 2024) Yu, Xingmiao; Xiang, Jianfei; Shi, Qitao; Li, Luwen; Wang, Jiaqi; Liu, Xiangqi; Zhang, Cheng; Wang, Zhipeng; Zhang, Junjin; Hu, Huimin; Bachmatiuk, Alicja; Trzebicka, Barbara; Chen, Jin; Guo, Tianxiao; Shen, Yanbin; Choi, Jinho; Huang, Cheng; Rümmeli, Mark H.
Graphitic carbon materials are widely used in lithium-ion batteries (LIBs) due to their stability and high conductivity. However, graphite anodes have low specific capacity and degrade over time, limiting their application. To meet advanced energy storage needs, high-performance graphitic carbon materials are required. Enhancing the electrochemical performance of carbon materials can be achieved through boron and nitrogen doping and incorporating 3D structures such as carbon nanocages (CNCs). In this study, aluminum (Al) is introduced into CNC lattices via chemical vapor deposition (CVD). The hollow structure of CNCs enables fast electrolyte penetration. Density functional theory (DFT) calculations show that Al doping lowers the intercalation energy of Li+. The Al-boron (B)-nitrogen (N-doped CNC (AlBN-CNC) anode demonstrates an ultrahigh rate capacity (approximate to 300 mAh g(-1) at 10 A g(-1)) and a prolonged fast-charging lifespan (862.82 mAh g(-1) at 5 A g(-1) after 1000 cycles), surpassing the N-doped or BN-doped CNCs. Al doping improves charging kinetics and structural stability. Surprisingly, AlBN-CNCs exhibit increased capacity upon cycling due to enlarged graphitic interlayer spacing. Characterization of graphitic nanostructures confirms that Al doping effectively tailors and enhances their electrochemical properties, providing a new strategy for high-capacity, fast-charging graphitic carbon anode materials for next-generation LIBs.
Factors controlling the organ-specific T1 contrast effect of silica nanoparticles co-doped with both Mn2+ ions and oleate-coated iron oxides
(Elsevier, 2024) Bochkova, Olga; Stepanov, Alexey; Bebyakina, Anastasiya; Smekalov, Daniil; Kholin, Kirill; Nizameev, Irek; Romashchenko, Alexander; Zavjalov, Evgenii; Lubina, Anna; Voloshina, Alexandra; Tyapkina, Oksana; Tarasov, Maxim; Sultanov, Timur; Rümmeli, Mark H.; Salnikov, Vadim; Budnikova, Yulia; Mustafina, Asiya
The present work introduces the synergistic effect of co-doping of both oleate-coated superparamagnetic iron oxide nanoparticles (SPIONs) and Mn(NO3)(2) into silica nanoparticles (SNs) on the T-1-relaxivity relaxivity of Mn2+ ions. The observed synergism can be attributed to the limited oxidation of Mn(2+ )ions when they are doped into the outer layer of SNs doped with SPIONs, despite the alkaline synthesis conditions. The electrochemical behaviour of the manganese ions inside co-doped SNs corroborates the predominance of their oxidation state (2+). Moreover, the T-1 relaxivities of co-doped SNs have been determined to be 20.0 mM(- 1 )s(- 1 ) and 30.0 mM(- 1 ) s(- 1 ) at 0.47 T. The T-2 relaxivity of co-doped SNs can be tuned by incorporating 6 or 13 nm SPIONs with different saturation magnetizations, which allows the T-2/T-1 2 /T (1) relaxation ratios to be limited to 0.8-5.9. The incorporation of amino groups on the surface of co-doped SNs by substituting silanol groups with propylamino groups reduces T-1 relaxivity to 9.0 mM(- 1) s(- 1) , which is nevertheless sufficient to provide a brightening of the abdominal organs and mouse brain in magnetic resonance imaging at 11.7 T. The preferential localisation of co-doped SNs in the kidneys and intestines compared to the liver is a consequence of the specificity of amino-substituted SNs compared to bare SNs.
Coordination-regulated epitaxial growth for 2D/3D perovskite vertical alignment heterostructure
(Elsevier, 2024) Zhao, Guoxiang; Chen, Yuan; Cong, Shan; Li, Lutao; Wang, Chen; Du, Xinyu; Liu, Ruirui; Lu, Jing; Liu, Yu; Chen, Gaoyuan; Zhang, Sihan; Zhang, Liya; Rümmeli, Mark H.; Zou, Guifu
In situ growth of suspended zirconene islets inside graphene pores
(Wiley, 2024) Mendes, Rafael G.; Ta, Huy Quang; Gemming, Thomas; van Gog, Heleen; van Huis, Marijn A.; Bachmatiuk, Alicja; Rümmeli, Mark H.
Experiments using a transmission electron microscope decomposed zirconium acetylacetonate with an electron beam, forming zirconium nanoparticles on graphene. Continued electron irradiation transformed these nanoparticles into atomically thick zirconium islets (zirconene islets) within the graphene lattice. The electron beam caused zirconium atom dislocations and vacancies that are rapidly refilled, a process repeating until the vacancies evolved into zirconium nanoribbons before breaking. This study offers insights into the electron-driven growth and degradation of zirconene islets, showcasing a method to fabricate freestanding zirconenes for use as atomically thin coatings in extreme environments.
Use of thermal analysis for the study of the adsorption of pharmaceuticals from water
(Elsevier, 2024) Bednárek, Jan; Šiler, Pavel; Švec, Jiří; Vráblová, Martina
The contamination of water with pharmaceuticals is one of the serious problems in the modern world. Their occurrence in surface- and groundwater brings a risk to the environment as well as human health. Therefore, many methods are studied in order of their removal. Adsorption on activated carbon belongs to the most popular ones. This paper is aimed at using thermal analysis to study the adsorption of analgesic paracetamol (acetaminophen) on activated carbon. Adsorption experiments including adsorption kinetics, adsorption isotherms, the effect of temperature and the effect of pH were also performed. Two different samples of commercial activated carbon (one powdered activated carbon (PAC) and one granular activated carbon (GAC)) and different initial concentrations of paracetamol were used. Equilibrium concentrations were determined with the aid of UV-VIS spectrophotometry and compared with thermogravimetric curves. Adsorption of paracetamol led to an appearance of a weak additional DTG peak at around 300-400 degrees C and negligible DTA effect in this temperature range. The DTG peaks at around 600 degrees C were reduced, indicating the removal of the groups left after activation on the carbon surface. The low height and width of DTG peaks and DTA effects were connected with a low mass ratio of adsorbed paracetamol related to the adsorbent mass (about 10-20%), more distinctive peaks could be achieved by the use of better adsorbing contaminants with higher molar mass.
Photocatalytic reduction of CO2 over Ti3+ self-doped TiO2-based nanomaterials
(Elsevier, 2024) Ricka, Rudolf; Wanag, Agnieszka; Kusiak-Nejman, Ewelina; Moszyński, Dariusz; Filip Edelmannová, Miroslava; Reli, Martin; Baďura, Zdeněk; Zoppellaro, Giorgio; Zbořil, Radek; Morawski, Antoni W.; Kočí, Kamila
In this study, we explored the photocatalytic efficacy of Ti3+-doped TiO2-based photocatalysts for CO2 reduction. The Ti3+ self-doped photocatalysts were synthesized using a straightforward chemical reduction with sodium borohydride (NaBH4). Our investigation aimed to elucidate the intricate interplay between the synthesis process and the quantity of NaBH4 reductant on the physical-chemical and photocatalytic attributes of the defective TiO2-based photocatalysts. We explored three different commercially available TiO2 materials labeled P25, (S) TiO2, and KRONOClean7050, which were reduced (2 g of TiO2) with 0.75 and 1.5 g of NaBH4. The reduction with 0.75 g of NaBH4 led to a significant decrease of photocatalytic activity in all three cases. It was caused by clogging of the photocatalysts surface by sodium ions which resulted in the surface recombination of charge carriers. Oppositely, the reduction with 1.5 g of NaBH4, led to an increase of the photocatalytic activity with superior performance of KRONOClean7050. The comprehensive characterization of all the samples explained this superior performance of KC7050_RED_1.5 sample. Importantly, it did not contain any amorphous phase and the crystal size was two times higher compared to other 2 samples reduced by 1.5 g of NaBH4. In the addition to higher crystallinity, the formation of a disordered TiO2_x layer, enriched with Ti3+ defects and oxygen vacancies, was confirmed. These structural features enhance the light absorption and mitigate undesired recombination of photogenerated charge carriers. These results would trigger farther investigation of defect engineering towards enhancement of the efficiency of metal oxide photocatalysts.
Synergistic effect of manganese on zirconia and ceria supports for improving photoreduction of CO2
(Elsevier, 2024) Sagar, Tatiparthi Vikram; Kumar, Praveen; Filip Edelmannová, Miroslava; Ricka, Rudolf; Reli, Martin; Kočí, Kamila; Nadrah, Peter; Emin, Saim; Sever Škapin, Andrijana; Štangar, Urška Lavrenčič
Photocatalytic CO2 reduction in the liquid phase at neutral pH conditions has been studied employing high surface area Mn-modified cubic CeO2 and amorphous ZrO2 catalysts. Results of the photocatalytic reduction of CO2 to methane are promising on Mn-modified ZrO2 and comparable with the noble metal-based photocatalysts. The surface area of both supports CeO2 and ZrO2 increased with Mn addition. Two broad diffraction peaks in Xray diffractograms indicate that the ZrO2 support is in the amorphous phase and Mn addition showed no considerable change. High intense diffraction peaks for CeO2 support illustrated the cubic fluorite phase and Mn addition to CeO2 support decreased the crystallite size due to the incorporation of Mn ions into the CeO2 lattice. XPS study revealed the stabilization of Mn in a lower oxidation state i.e., Mn2+ and Mn3+, with ZrO2 support than with CeO2 support. The superior specific capacitance of the Mn-modified ZrO2 catalyst indicates the enhanced synergy of active Mn species and support. Among the studied catalysts, Mn-modified ZrO2 photocatalyst exhibited the highest activity and selectivity for photoreduction of CO2 to methane and CO.
High-performance photoelectrochemical hydrogen production using asymmetric quantum dots
(Wiley, 2024) Wang, Kanghong; Wang, Chao; Tao, Yi; Tang, Zikun; Benetti, Daniele; Vidal, François; Liu, Yu; Rümmeli, Mark H.; Zhao, Haiguang; Rosei, Federico; Sun, Xuhui
Solar-driven photoelectrochemical (PEC) reactions using colloidal quantum dots (QDs) as photoabsorbers have shown great potential for the production of clean fuels. However, the low H2 evolution rate, consistent with low values of photocurrent density, and their limited operational stability are still the main obstacles. To address these challenges, the heterostructure engineering of asymmetric capsule-shaped CdSe/CdxZn1-xSe QDs with broad absorption and efficient charge extraction compared to pure-shell QDs is reported. By engineering the shell composition from pure ZnSe shells into CdxZn1-xSe gradient shells, the electron transfer rate increased from 4.0 × 107 s−1 to 32.7 × 107 s−1. Moreover, the capsule-shaped architecture enables more efficient spatial carrier separation, yielding a saturated current density of average of 25.4 mA cm−2 under AM 1.5 G one sun illumination. This value is the highest ever observed for QDs-based devices and comparable to the best-known Si-based devices, perovskite-based devices, and metal oxide-based devices. Furthermore, PEC devices based on heterostructured QDs maintained 96% of the initial current density after 2 h and 82% after 10 h under continuous illumination, respectively. The results represent a breakthrough in hydrogen production using heterostructured asymmetric QDs.
Virgin polymers via pyrolysis – A review of heteroatom removal options
(Elsevier, 2024) Snow, Jan; Kuráň, Pavel; Kašpárek, Aleš; Leštinský, Pavel; Suchopa, Robert
This review is dedicated to the removal of heteroatoms from plastic pyrolysis liquid products for use in the petrochemical industry. The chapters are devoted to removing individual groups of heteroatoms and summarizing the current scientific knowledge on the subject. Attention is given to the possibilities of heteroatom removal at all stages of the recycling process except sorting. Most of the findings in this area relates to the halogen removal, where high efficiencies can be achieved already in the pyrolysis process. In contrast, the removal of other heteroatoms has mainly been studied in the liquid product, usually in a hydrogen atmosphere and in the presence of a catalyst. It seems economically feasible to remove the heteroatoms as early as possible in the recycling process. This can be achieved in part by washing the waste plastic in water, which can remove a large proportion of the heteroatoms present as impurities. The work highlights the need for comprehensive mapping of heteroatoms in products and, in many cases, the need for more data regarding their removal. Finally, conclusions are drawn for further research in this area.
Co-composting of sewage sludge as an effective technology for the production of substrates with reduced content of pharmaceutical residues
(Elsevier, 2024) Vráblová, Martina; Smutná, Kateřina; Chamrádová, Kateřina; Vrábl, Daniel; Koutník, Ivan; Rusín, Jiří; Bouchalová, Markéta; Gavlová, Anna; Sezimová, Hana; Navrátil, Martin; Chalupa, Richard; Tenklová, Barbora; Pavlíková, Jitka
Sewage sludge is a valuable source of elements such as phosphorus and nitrogen. At the same time, heavy metals, emerging organic compounds, micropollutants (pharmaceuticals, pesticides, PCPs, microplastics), or some potentially dangerous bacteria can be present. In this study, the sewage sludge was aerobically treated by composting with other materials (co -composted), and the resulting substrate was tested for suitability of its use in agriculture. Closer attention was focused on the pharmaceuticals (non -steroidal antiphlogistics, sartanes, antiepileptics, caffeine, and nicotine metabolites) content and ecotoxicity of the resulting substrates in the individual phases of sludge co -composting. It has been verified that during co -composting there is a potential for reduction of the content of pharmaceutical in the substrates up to 90 %. The course of the temperature in the thermophilic phase is decisive. Growth and ecotoxicity experiments demonstrated that with a suitable co -composting procedure, the resulting stabilized matter is suitable as a substrate for use in plant production, and the risk of using sewage sludge on agricultural land is substantially reduced.
Modulating p-type doping of two dimensional material palladium diselenide
(Springer Nature, 2023) Yang, Jiali; Liu, Yu; Wang, En-Yang; Pang, Jinbo; Huang, Shirong; Gemming, Thomas; Bi, Jinshun; Bachmatiuk, Alicja; Jia, Hao; Hu, Shu-Xian; Jiang, Chongyun; Liu, Hong; Cuniberti, Gianaurelio; Zhou, Weijia; Rümmeli, Mark H.
The van der Waals heterostructures have evolved as novel materials for complementing the Si-based semiconductor technologies. Group-10 noble metal dichalcogenides (e.g., PtS2, PtSe2, PdS2, and PdSe2) have been listed into two-dimensional (2D) materials toolkit to assemble van der Waals heterostructures. Among them, PdSe2 demonstrates advantages of high stability in air, high mobility, and wide tunable bandgap. However, the regulation of p-type doping of PdSe2 remains unsolved problem prior to fabricating p–n junction as a fundamental platform of semiconductor physics. Besides, a quantitative method for the controllable doping of PdSe2 is yet to be reported. In this study, the doping level of PdSe2 was correlated with the concentration of Lewis acids, for example, SnCl4, used for soaking. Considering the transfer characteristics, the threshold voltage (the gate voltage corresponding to the minimum drain current) increased after SnCl4 soaking treatment. PdSe2 transistors were soaked in SnCl4 solutions with five different concentrations. The threshold voltages from the as-obtained transfer curves were extracted for linear fitting to the threshold voltage versus doping concentration correlation equation. This study provides in-depth insights into the controllable p-type doping of PdSe2. It may also push forward the research of the regulation of conductivity behaviors of 2D materials.
Boosting flexible electronics with integration of two-dimensional materials
(Wiley, 2024) Hou, Chongyang; Zhang, Shuye; Liu, Rui; Gemming, Thomas; Bachmatiuk, Alicja; Zhao, Hongbin; Jia, Hao; Huang, Shirong; Zhou, Weijia; Xu, Jian-Bin; Pang, Jinbo; Rümmeli, Mark H.; Bi, Jinshun; Liu, Hong; Cuniberti, Gianaurelio
Flexible electronics has emerged as a continuously growing field of study. Two-dimensional (2D) materials often act as conductors and electrodes in electronic devices, holding significant promise in the design of high-performance, flexible electronics. Numerous studies have focused on harnessing the potential of these materials for the development of such devices. However, to date, the incorporation of 2D materials in flexible electronics has rarely been summarized or reviewed. Consequently, there is an urgent need to develop comprehensive reviews for rapid updates on this evolving landscape. This review covers progress in complex material architectures based on 2D materials, including interfaces, heterostructures, and 2D/polymer composites. Additionally, it explores flexible and wearable energy storage and conversion, display and touch technologies, and biomedical applications, together with integrated design solutions. Although the pursuit of high-performance and high-sensitivity instruments remains a primary objective, the integrated design of flexible electronics with 2D materials also warrants consideration. By combining multiple functionalities into a singular device, augmented by machine learning and algorithms, we can potentially surpass the performance of existing wearable technologies. Finally, we briefly discuss the future trajectory of this burgeoning field. This review discusses the recent advancements in flexible sensors made from 2D materials and their applications in integrated architecture and device design.
Titanium substitution facilitating oxygen and manganese redox in sodium layered oxide cathode
(Wiley, 2024) Zhou, Junhua; Hu, Huimin; Wang, Jiaqi; Shi, Qitao; Lian, Xueyu; Liu, Lijun; Bachmatiuk, Alicja; Sun, Jingyu; Yang, Ruizhi; Choi, Jin-Ho; Rümmeli, Mark H.
Sodium layered oxide with anion redox activity (SLO-A) stands out as a promising cathode material for sodium-ion batteries due to its impressive capacity and high voltage resulting from Mn- and O-redox processes. However, the SLO-A faces significant challenges in cycling stability and rate performance, primarily due to the poor reversibility and sluggish kinetics of the O-redox. In this study,a novel Ti-doped material, Na2/3Li2/9Mn53/72Ti1/24O2 (NLMTO), exhibiting remarkable characteristics such as a notable rate capacity (130 mAh g−1 at 3C, where 1C equals 200 mA g−1) and excellent cycling retention (85.4% after 100 cycles at 0.5C) is introduced. Employing electrochemical differential analyses, the contributions to the superior performance arising from the Mn- and O-redox processes are quantitatively delineated. The optimized performance of NLMTO is attributed, in part, to the enhanced stability of both bulk and interface structures. The introduction of Ti through substitution not only contributes to this stability but also allows for the fine-tuning of the material’s electron configurations. This is achieved by augmenting the density of states near the Fermi energy level, as well as elevating the O 2p and Mn 3d orbits. This research advances sodium-ion battery technology
Density functional theory and molecular dynamics study on the growth of graphene by chemical vapor deposition on copper substrate
(AIP Publishing, 2024) Li, Qihang; Luo, Jinping; Li, Zaoyang; Rümmeli, Mark H.; Liu, Lijun
Chemical vapor deposition is an affordable method for producing high-quality graphene. Microscopic defects in graphene grown on copper substrates, such as five- and seven-membered rings, degrade the quality of graphene. Therefore, it is essential to study the growth process and factors affecting the quality of graphene on copper surfaces. In this study, first-principles calculations based on density functional theory show that the four-step dehydrogenation reaction of methane is endothermic, with the energy barrier for the last dehydrogenation step being relatively high. Additionally, CH forms dimers on the copper surface with a lower energy barrier and trimers with a higher energy barrier, indicating that carbon dimers are the primary precursor species for graphene growth in the early stages. Subsequently, in molecular dynamics simulations, the analytical bond-order potential based on quantum mechanics is employed. The results reveal that the growth of graphene on the copper surface involves the diffusion and gradual nucleation of carbon dimers in the early stages, the gradual enlargement of graphene domains in the intermediate stages, and the gradual merging of graphene domain boundaries in the later stages. Moreover, the growth of graphene on the copper substrate follows a self-limiting growth mode. Increasing the deposition interval of carbon atoms and reducing the carbon atom deposition velocity contribute to enhancing the quality of graphene grown on the copper substrate.
Monomolecular membrane-assisted growth of antimony halide perovskite/MoS2 van der Waals epitaxial heterojunctions with long-lived interlayer exciton
(American Chemical Society, 2024) Zhou, Zhicheng; Zhu, Juntong; Li, Lutao; Wang, Chen; Zhang, Changwen; Du, Xinyu; Wang, Xiangyi; Zhao, Guoxiang; Wang, Ruonan; Li, Jiating; Lu, Zheng; Zong, Yi; Sun, Yinghui; Rümmeli, Mark H.; Zou, Guifu
Epitaxial growth stands as a key method for integrating semiconductors into heterostructures, offering a potent avenue to explore the electronic and optoelectronic characteristics of cutting-edge materials, such as transition metal dichalcogenide (TMD) and perovskites. Nevertheless, the layer-by-layer growth atop TMD materials confronts a substantial energy barrier, impeding the adsorption and nucleation of perovskite atoms on the 2D surface. Here, we epitaxially grown an inorganic lead-free perovskite on TMD and formed van der Waals (vdW) heterojunctions. Our work employs a monomolecular membrane-assisted growth strategy that reduces the contact angle and simultaneously diminishing the energy barrier for Cs3Sb2Br9 surface nucleation. By controlling the nucleation temperature, we achieved a reduction in the thickness of the Cs3Sb2Br9 epitaxial layer from 30 to approximately 4 nm. In the realm of inorganic lead-free perovskite and TMD heterojunctions, we observed long-lived interlayer exciton of 9.9 ns, approximately 36 times longer than the intralayer exciton lifetime, which benefited from the excellent interlayer coupling brought by direct epitaxial growth. Our research introduces a monomolecular membrane-assisted growth strategy that expands the diversity of materials attainable through vdW epitaxial growth, potentially contributing to future applications in optoelectronics involving heterojunctions.

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