Dual-functional Materials Research Articles

Carbon foam/reduced graphene oxide/paraffin composite phase change material for electromagnetic interference shielding and thermal management

To address the issues of electromagnetic interference (EMI) shielding and thermal management during operation of electronic devices, carbon foam/reduced graphene oxide/paraffin dual-functional composite phase change material (c-MG/PA) is fabricated via reductive assembly and vacuum impregnation. The carbonized melamine foam and graphene jointly construct a three-dimensional electrical conductive and thermal conductive synergistic network. EMI shielding efficiency of c-MG/PA at thickness of 2 mm is up to 49 dB dominated by the electromagnetic absorption mechanism of the double conductive carbon network, far outstripping the commercial application standard of 20 dB. The phase change enthalpy of c-MG/PA reaches at least 196.3 J·g−1, and the relative enthalpy efficiency is above 97.4 %. Because of the enhancement of three-dimensional heat transfer network, the thermal conductivity of c-MG/PA is 324 % higher than that of paraffin. By using c-MG/PA as thermal management material in analog electronic chip, the chip temperature remarkably drops by 17.1 °C. In addition, c-MG/PA also exhibits superior shape stability, cycling stability and thermal stability, ensuring the reliability and security for long-term use in electronic devices. The results reveal that c-MG/PA possesses great application potential in EMI shielding and thermal management.

Upgrading CO2 from simulated power plant flue gas via integrated CO2 capture and dry reforming of methane using Ni-CaO

Integrated CO2 capture and utilisation via dry reforming of methane (ICCU-DRM) represents a promising and profitable route for directly capturing and converting CO2 from various CO2 sources. However, the influence of realistic flue gas conditions on ICCU-DRM remains unknown and challenging. Herein, we investigated the influence of the presence of H2O and O2 in power plant flue gas on integrated CO2 capture and DRM using Ni10-CaO dual functional material (DFM). It is found that H2O promoted the kinetics of CO2 capture, while the O2 oxidised Ni into NiO and prohibited the performance of utilisation of the captured CO2 during DRM. Specifically, the delay of pre-reduction of NiO and the coverage of catalytic sites by the formed CaCO3 decreased the process performance and efficiency. The reduction of NiO would instantly generate CO2 and hinder the contact between CH4 and Ni, resulting in a lower initial catalytic performance during the CO2 utilisation (DRM) of ICCU. Due to the occurrence of CH4 decomposition in DRM, the following CO2 capture step would produce CO in the flue gas, which could be problematic, owing to the carbon gasification reactions. An extra step of carbon steam gasification (CSG) after DRM could effectively remove most of the deposited carbon and by-produce syngas. Subsequently, the small amount of carbon residue after the CSG step could be preferentially combusted by O2 into CO2 in flue gas, and then be captured by CaO instead of generating CO. This study demonstrates the feasibility and challenges of ICCU-DRM under simulated power plant flue gas conditions and provides potential insights for future investigation and deployment of this integrated process.

Cyclic performance in CO2 capture-methanation of bifunctional Ru with different base metals: Effect of the reactivity of COx ad-species

Bifunctional materials based on Ru nanoparticles and an alkaline metal (K, Na or Ba) have been scrutinized for several cycles of CO2 capture and subsequent methanation at different temperatures from 250 ºC to 450 ºC. The optimum performance in terms of stable cyclic operation, amount of captured CO2 and relevant methane productivity was attained at different temperature window for each material. For the materials here prepared, the limiting lower operation temperature of stable cyclic performance was determined by the methanation kinetics, which depended on reactivity of COx ad-species captured with each alkaline metal. The highest activity was found with Ba-containing materials, which exhibited a stable and relevant cyclic CH4 productivity at 250 ºC, being one of the lowest operation temperatures reported for a dual functional material to date. This material exhibited stable cyclic performance also in the presence of O2 and H2O, although the CH4 productivity decreases slightly and reversibly compared to that using CO2 containing gas free of O2 and H2O.

MxOy (M = Mg, Zr, La, Ce) modified Ni/CaO dual functional materials for combined CO2 capture and hydrogenation

The integrated CO2 capture and utilization has recently attracted attention as a promising approach to reduce CO2 emissions as well as produce value-added chemicals and fuels. Herein, metal oxides (MxOy, M = Mg, Zr, La, and Ce) modified Ni/CaO dual functional materials (M-Ni/Ca DFMs) were synthesized and applied to the combined CO2 capture and hydrogenation using a single reactor at one temperature. The La–Ni/Ca showed the highest CO2 adsorption capacity (13.8 mmol/g), CO2 conversion (64.3%) and CO yield (8.7 mmol/g). Results indicated that the addition of metal oxides increased the number of basic sites which played important role in efficient CO2 capture. The high activities of M-Ni/Ca were attributed to the formation of highly dispersed small-sized Ni particles. Furthermore, the La–Ni/Ca exhibited excellent cyclic stability after 20 cycles due to the La2O3 as a physical barrier and a support for inhibiting the growth and sintering of CaO and Ni particles.

Harnessing the structural attributes of NiMg-CUK-1 MOF for the dual-function capture and transformation of carbon dioxide into methane

Carbon capture and conversion into chemical fuels are often considered distinct processes, whereby a sorbent is responsible for enriching a CO2 stream while a catalyst facilitates transformation into value-added commodities. Herein, we implement NiMg-CUK-1, a metal–organic framework (MOF) possessing the characteristics of both adsorbent and catalyst for the sequential capture and conversion of CO2 to methane (CH4). By harnessing the disparity in thermal stability between Ni- and Mg-CUK-1 analogues, Ni nanoparticles are preferentially generated throughout the preserved Mg portion of the framework. Tuning the Ni:Mg ratio and the NiMg-CUK-1 treatment temperature maximizes catalytic performance while preserving a substantial portion of the CO2 capture functionality inherent to the MOF. The optimized NiMg-CUK-1 is deployed in a dual-mode reactor system that alternates between ambient temperature CO2 capture and methanation under mild reaction conditions (250 °C). After five cycles, the optimal NiMg-CUK-1 reaches a levelled-out performance of 1.46 ± 0.24 mmol CO2 captured g−1, and 1.52 ± 0.23 mmol CH4 produced g−1, surpassing similar sorbent-based catalysts reliant on the chemical looping of metal oxides and carbonates. The introduced approach paves the way for combined capture and conversion of CO2 using a single dual-functional material capable of both low-temperature CO2 desorption and CH4 production.

Two Stable Cd-MOFs as Dual-Functional Materials with Luminescent Sensing of Antibiotics and Proton Conduction.

Construction and investigation of dual-functional metal-organic frameworks (MOFs) with luminescent sensing and proton conduction provide widespread applications in clean energy and environmental monitoring fields. By selecting a phosphonic acid ligand 4-pyridyl-CH2N(CH2PO3H2)2 (H4L) and coligand 2,2'-biimidazole (H2biim), two cadmium-based MOFs [Cd1.5(HL)(H2biim)0.5] (1) and (H4biim)0.5·[Cd2(L)(H2biim)Cl] (2) with different structures and properties have been hydrothermally synthesized by controlling reaction temperature. Based on the excellent thermal and chemical stabilities, and good luminescent stabilities in water solution, 1 and 2 can serve as luminescent sensors of chloramphenicol (CAP) with different quenching constant (KSV) values and detection limits (LODs) in water, simulated environmental system, and real fish water system. Meanwhile, different sensing effects and possible sensing mechanisms are analyzed in detail. Moreover, 1 and 2 can also serve as good proton-conducting materials. The proton conductivities can reach up to 1.41 × 10-4 S cm-1 for 1 and 1.02 × 10-3 S cm-1 for 2 at 368 K and 95% relative humidity (RH). Among them, 2 shows better luminescent sensing and proton conduction performance than 1, which indicates that different crystal structures have a great impact on the properties of MOFs. Through the discussion of the relationship between structures and properties in detail, the possible reasons for the differences in properties are obtained, which can provide theoretical guidance for the rational design of this kind of dual-functional MOFs in the future.

Adsorption of methyl orange and chromium (VI) using Momordica charantia L. leaves: a dual functional material for environmental remediation

Adsorption of methyl orange and chromium (VI) using Momordica charantia L. leaves: a dual functional material for environmental remediation

Extended aging of Ru-Ni, Na2O/Al2O3 dual function materials (DFM) for combined capture and subsequent catalytic methanation of CO2 from power plant flue gas

This study investigates the use of catalytic Ru and Ni combinations, intimately mixed with Na2O supported on γ-Al2O3 DFMs (dual function materials). We refer to these as dual function since one material – composed of an alkaline sorbent and catalytic component intimately dispersed on a high surface area carrier – can be used to capture CO2 from power plant flue gas and subsequently upgrade it to methane. The goal is to reduce the Ru content by combining it with catalytic Ni. Due to the presence of O2 in flue gas, Ni-only DFMs are not suitable candidates as they are oxidized and cannot be reactivated at temperatures below 550 °C. However, with the addition of small amounts of Ru, NiO can be reduced at DFM operating temperatures (∼300 °C, consistent with the exhaust temperature of natural gas flue gas), increasing catalytic sites for methanation. Several Ru + Ni combinations are investigated (0.5 % Ru, x% Ni, 6.1 % “Na2O”/Al2O3, x = 1, 5, 10, 20) for cyclic capture/methanation performance to identify an optimal formulation. 0.5 % Ru, 5 % Ni, 6.1 % “Na2O”/Al2O3 DFM is then aged in simulated, O2– and steam-containing natural gas flue gas. Aging over 60 cycles shows that there is steady deactivation in performance with XRD and STEM/EDS showing that the formation of inactive and stable NiAl2O4 is the primary cause for decreased methanation ability.

Calcium looping of CO2 capture coupled to syngas production using Ni-CaO-based dual functional material

Calcium looping (CaL), which involves carbonation of CaO by CO2 and regeneration of CaO through the conversion of the captured CO2 into useful products, shows promise for carbon capture and utilization. By integrating CaL with methane dry reforming (DRM), the captured CO2 can be converted into syngas, a valuable chemical feedstock and fuel. Herein, a dual functional material (DFM) composed of CaO (CO2 adsorbent), Ni (DRM catalyst) and CeO2 (promoter for DRM) had been developed to drive the CaL-DRM tandem processes. The CaO-Ni-CeO2 DFM possessed high performance of cyclic CaL-DRM: high CO2 uptake efficiency (10.3 mmolCO2/gCaO), high H2 and CO yields (754.4 mmolH2/gNi and 454.6 mmolCO/gNi), moderate required temperature for carbonation (450 °C) and subsequent methane dry reforming (680 °C), and sufficiently high stability. The carbonation of CaO was strongly influenced by the basicity of the material, and the conversion of CH4 with the captured CO2 was affected by the Ni dispersion in the material. Overall, our work demonstrates a prototype study of using a temperature-programmed reaction platform for a quantitative, real-time analysis on CaL-DRM kinetics. The mechanistic understanding of CaL-DRM by the CaO-Ni-CeO2 DFM were elucidated, showing promise for the catalyst optimizations.

Tailoring the performance of Ni-CaO dual function materials for integrated CO2 capture and conversion by doping transition metal oxides

Transition metal oxides (TMOs) doping is proposed as one effective strategy to improve CO2 capture and conversion performance of Ni-CaO dual function materials (DFMs). The effect of single and binary TMOs doping on structure–property-activity relationships of Ni-CaO DFMs for integrated CO2 capture and in-situ reverse water gas shift (RWGS) is investigated. ZrO2 doping enhances the surface basicity and reducibility of Ni-CaO DFMs for improved CO2 uptakes and reinforced catalytic activity. ZrO2 doping also endows Ni-CaO DFMs with improved working stability by forming CaZrO3 solid solution, which acts as physical barrier to retard the agglomeration and sintering of CaO and NiO species. Doping binary metal oxides of ZrO2-CeO2 further boosts the oxygen vacancy concentration in the DFMs for promoted CO2 activation and conversion and stabilized CO yield. The desired Ni-CaO-6ZrO2-6CeO2 DFMs shows a higher CO2 conversion of 72.1% and a lower decay rate of 12.0% for CO yield in consecutive cycles.

A perspective on bridging academic research and advanced testing on a path towards pilot plant implementation: A case study of integrating CO2 capture and catalytic conversion with dual function materials

As climate change intensifies, the challenges associated with CO2, including emissions mitigation, atmospheric CO2 abatement, and conversion to valuable, carbon-based products will persist for decades. There is an abundance of academic research that addresses the need for CO2 capture and conversion materials, and many of the solutions examined in the academy have shown promise under ideal conditions. The primary message of this perspective is to recognize the value of initial testing under ideal laboratory conditions while emphasizing the pressing need for further evaluations that simulate the real conditions expected in the final application. By expanding laboratory test parameters to include more realistic elements, materials can be more rigorously validated for the intended application. Success at the small-scale warrants scaled up bench and pilot plant evaluations in advance of eventual commercialization. This perspective will use dual function materials (DFMs) as a case study for discussing a scalable approach to academic research of CO2 capture and catalytic conversion. These materials combine supported adsorbents and catalysts for integrated CO2 capture from point sources and ambient air and subsequent conversion to renewable methane.

Removal of water-soluble lignin model pollutants with graphene oxide loaded ironic sulfide as an efficient adsorbent and heterogeneous Fenton catalyst

Advanced oxidation processes (AOPs) have gained extensive attentions in organic decontamination in past decades. Iron-contained compound is an interesting material due to its adsorptive and catalytic performance, which has been applied widely in AOPs. Thus, graphene oxide (GO)-Fe3S4 composite was synthesized by a solvothermal process and assessed as an effective adsorptive and catalytic dual functional material in this work. The composite displayed prominent adsorptive and heterogeneous Fenton-like catalytic performance, which was affected by preparation condition and the reactive parameters in catalytic system. Under optimized reactive conditions, the GO-Fe3S4 composite yielded rapid degradation of vanillic acid, which the corresponding apparent rate constant was 1.81 × 10−1 min−1. Catalytic mechanism analysis revealed that the main oxygen species was hydroxyl radicals bounded on the surface of the composite. And the generation of •O2– was contributed to the conversion of H2O2 to •OH. The analysis of degradation intermediates of vanillic acid and p-hydroxybenzoic showed that these compounds could be mineralized to small molecules. The prominent enhanced heterogeneous Fenton-like catalytic performance of GO-Fe3S4 was due to a larger specific surface area, plenty of reductive active sites in the composite and a high mass transfer efficiency of oxidizing radicals in the reactive system.

Dual function naphthalimide modified mesoporous silica for organic pollutant sensing and removal from water

Dual-function materials for the selective sensing and adsorption of multiple dyes simultaneously are still challenging to prepare. Herein, a naphthalimide functionalized SBA–15 fluorescent sensor and adsorbent, namely, TPNI–SBA–15, was developed for the simultaneous detection and adsorption of the anionic dye congo red (CR) and the cationic dyes methylene blue (MLB) and malachite green (MG). The fluorescence intensity of TPNI–SBA–15 at 531 nm selectively quenched by CR, MLB and MG. The detection of CR was based on inner filter effect mechanism, and the detection of MLB and MG was attributed to the combined mechanism of electrostatic interaction, electron transfer and fluorescence resonance energy transfer. Limits of detection of 0.03, 0.10 and 0.26 μM, and limits of quantification of 0.10, 0.33 and 0.85 μM were estimated for the determination of CR, MLB and MG, respectively. The satisfactory recoveries from 99.72 to 104.80 % were acquired for detecting CR in tap water, with a relative standard deviation less than 2.9 %. Moreover, TPNI–SBA–15 can selectively remove CR, MLB and MG from water with a removal percentage reaching 100 %, 98.8 % and 61.5 %, respectively, within 1 min. TPNI–SBA–15 exhibited good dye adsorption and removal stability after three cycles of adsorption, desorption and regeneration. TPNI–SBA–15 also removes CR, MLB and MG from binary, ternary and quaternary dye mixtures conveniently and effectively. This work provided an economic strategy to realize simultaneous selective detection and adsorption of organic dyes by rationally introducing specific organic functional units into mesoporous structures. Keywords: Mesoporous silica; Organic dyes; Selective sensing; Selective adsorption.

Ca doping effect on the performance of La1−xCaxNiO3/CeO2-derived dual function materials for CO2 capture and hydrogenation to methane

CO2 valorization in form of synthetic natural gas is a convenient way to store large amounts of intermittent energy produced from renewable sources for long periods of time. Here reported research addresses the development of novel dual function materials (DFMs) for the utilization of CO2 from simulated post-combustion effluent by cyclic adsorption and in-situ methanation. These DFMs, obtained after the controlled reduction of 20% La1−xCaxNiO3/CeO2-type precursors (with x = 0–0.5), are widely characterized before and after catalytic tests. XRD diffractograms, H2-TPD experiments and STEM-EDS images denote that Ca-doping shows low influence on materials composition, slight detrimental effect on textural properties and no influence on Ni, La and Ce distribution. Meanwhile, the concentration of Ca-based species increases as long as La3+ substitution by Ca2+ increases, which leads to a progressively promotion of medium and, especially, strong basic sites concentration (CO2-TPD). As a result, the 20% La0.5Ca0.5NiO3/CeO2-derived DFM almost doubles (188.8 µmol g−1) the CH4 production of the 20% LaNiO3/CeO2-derived DFM (96.5 µmol g−1) at high temperatures. Indeed, this novel DFM enhances the methanation capacity of the conventional 15% Ni-15% CaO/Al2O3 DFM (143.0 µmol CH4 g−1), with higher stability during long-term experiments and adaptability under variable feed compositions, which further support the applicability of these novel DFMs. Thus, Ca doping emerges as an effective way of tailoring CO2 adsorption and in-situ hydrogenation to CH4 efficiency of 20% LaNiO3/CeO2-derived DFMs.

Site-selective synthesis of an amine-functionalized β-ketoenamine-linked covalent organic framework for improved detection and removal of Cu2+ ion from water

The development of new dual-functional materials for detection and removal of heavy metal ions is of great significance in environmental protection. Herein, a new amine-functionalized β-ketoenamine-linked covalent organic framework (termed as NH2–Th-Tfp COF) containing rich O,N,O′-chelating sites and free amine groups has been synthesized through the site-selective synthesis strategy under solvothermal conditions. The as-synthesized NH2–Th-Tfp COF shows strong fluorescence in water dispersion and can be used as highly sensitive and selective fluorescent probe for Cu2+ detection. As a sensing platform, the limit of detection for NH2–Th-Tfp COF toward Cu2+ ion is estimated to be 0.19 ​μM. Besides, the NH2–Th-Tfp COF possesses high adsorption capacity of 153 ​mg/g toward Cu2+ ion in aqueous solution. More importantly, this NH2–Th-Tfp COF exhibits higher sensitivity and larger adsorption capacity toward Cu2+ ion in comparison with the non-amine functionalized Th-Tfp COF, which may be attributed to the large number of free amine groups in the pore walls of NH2–Th-Tfp COF. The coordination interactions between Cu2+ ion with the O, N, O′-chelating sites and free amine groups in the pore walls of NH2–Th-Tfp COF can greatly enhance its recognition and absorption performances toward Cu2+ ion, as verified by X-ray photoelectron spectroscopy. This work may pave the way for designing new fluorescent COF materials with dual functions for simultaneous detection and removal of specific metal ions.

“1+1>2”: Highly efficient removal of organic pollutants by composite nanofibrous membrane based on the synergistic effect of adsorption and photocatalysis

• A dual-functional nanofibrous membrane material was prepared for wastewater remediation. • The adsorption facilitated and accelerated the photocatalytic degradation reaction. • The photocatalysis regenerated the adsorption active site and realized green recycle. • The synergistic effect of adsorption and photocatalysis was investigated systematically. • The synergy produced a “1+1>2” effect for highly efficient removal of pollutants. Adsorption and photocatalysis are regarded as two desirable technologies for wastewater remediation, but are still unsatisfactory in removal effect, eco-friendly regeneration and facile reusability. In this study, we developed a composite nanofibrous membrane material with excellent removal performance for organic pollutants based on synergistic adsorption and photocatalysis. A novel boron-doped, nitrogen-deficient graphitic carbon nitride (B-C 3 N 4 ) photocatalyst as well as an amphiphilic copolymer of methyl methacrylate and acrylic acid (p(MMA-AA)) were synthesized respectively, and then used to modify polyethersulfone for the fabrication of composite nanofibrous membrane with improved hydrophilicity, negatively-charge property and enhanced visible light response simultaneously. Subsequently, the synergistic effect of adsorption and photocatalytic degradation for organic pollutants were identified especially and resulted in an excellent removal efficiency even superior to the combination of adsorption and photocatalytic degradation, which could be called a “1+1>2” effect. In addition, the regeneration and reusability, the purification ability for multicomponent wastewater, and the photocatalytic mechanism, were investigated and discussed systematically. In this work, we not only prepared the nanofibrous membrane with synergistic effect of adsorption and photocatalysis, but also provided a versatile approach to design dual-functional support material to ensure the practical applications of powdery photocatalyst in wastewater treatment.

Layered-double-hydroxide-based Ni catalyst for CO2 capture and methanation

Ni-based catalysts prepared using layered double hydroxides (LDH) as precursors containing Mg and Ca are examined as dual-function materials for CO2 capture and methanation. X-ray diffraction, thermogravimetric analysis, H2 temperature-programmed reduction, N2 adsorption, and scanning transmission electron microscopy analyses revealed that the LDH-derived Ni catalysts form porous structures of composite oxides (MgO-NiO) containing 5-nm-sized micropores and highly dispersed 5–10-nm-sized Ni-metal nanoparticles. The methanation performance is investigated under isothermal cyclic operation with an O2-containing gas (10%-CO2/5%-O2/bal.-He) and 20%-H2/bal.-He at 320 °C; the results indicate that the LDH-derived Ni catalysts containing Ca, Mg, and Al exhibit high methanation activities. Mg contributes to the stabilization of the porous structure and enhances the Ni-metal dispersion, while Ca provides effective CO2 adsorption and storage sites.

In situ growth of ZIF-67-derived nickel-cobalt-manganese hydroxides on 2D V2CTx MXene for dual-functional orientation as high-performance asymmetric supercapacitor and electrochemical hydroquinone sensor

Designing dual-functional electrode materials for supercapacitors and pollutant sensors has attracted great interest from researchers for urgent demand in green energy and the environment. In this work, a novel electrode material V2CTx@NiCoMn-OH was successfully constructed for dual-functional orientation via a two-step synthesis strategy, in which the NiCoMn-OH with a three-dimensional (3D) hollow structure was fabricated by employing ZIF-67 as a template and simple anion exchange and composited with the two-dimensional (2D) layered V2CTx MXene. The intercalation of NiCoMn-OH can effectively limit the self-accumulation of V2CTx MXene nanosheets and build a 3D cross-linked hollow structure, thereby broadening the ion transport channel, exposing more active sites of V2CTx@NiCoMn-OH, and simultaneously improving the conductivity of NiCoMn-OH. Benefiting from the unique 3D cross-linked hollow structure, the optimized V2CTx@NiCoMn-OH-20 electrode material exhibits an excellent specific capacitance of 827.45 C g−1 at 1 A g−1. Furthermore, the electrode material has excellent capacitance retention of 88.44% after 10,000 cycles. Moreover, the V2CTx@NiCoMn-OH-20//AC ASC device displays a high energy density of 88.35 Wh kg−1 as well as high power density of 7500 W kg−1 during operation. Additionally, the V2CTx@NiCoMn-OH-20 exhibited excellent electrocatalytic performance in the detection of hydroquinone, including the low detection limit of 0.559 μM (S/N = 3) and the wide linear range of 2–1050 μM. Therefore, the prepared V2CTx@NiCoMn-OH-20 has great potential applications in the fields of supercapacitors and hydroquinone sensors.

Dual-Functional Nanostructures for Purification of Water in Severe Conditions from Heavy Metals and E. coli Bacteria

Because of industrial water, many groundwater sources and other water bodies have a strongly acidic medium. Increased bacterial resistance against multiple antibiotics is one of the main challenges for the scientific society, especially those commonly found in wastewater. Special requirements and materials are needed to work with these severe conditions and treat this kind of water. In this trend, nanolayered structures were prepared and modified in different ways to obtain an optimum material for removing different kinds of heavy metals from water in severe conditions, alongside purifying water from a Gram-negative bacteria (E. coli), which is an indication for fecal pollution. An ultrasonic technique effectively achieved this dual target by producing nanolayered structures looking like nanotapes with dimensions of 25 nm. The maximum removal percentages of the heavy metals studied (i.e., iron (Fe), copper (Cu), chromium (Cr), nickel (Ni), and manganese (Mn)) were 85%, 79%, 68%, 63%, and 61%, respectively for one prepared structure. In addition, this nanostructure showed higher antimicrobial activity against the most common coliform bacterium, E. coli (inhibition zone up to 18.5 mm). This study introduces dual-functional material for removing different kinds of heavy metals from water in severe conditions and for treating wastewater for Gram-negative bacteria (E. coli).

Robust Antibacterial Activity of Xanthan-Gum-Stabilized and Patterned CeO2-x-TiO2 Antifog Films.

Increased occurrence of antimicrobial resistance leads to a huge burden on patients, the healthcare system, and society worldwide. Developing antimicrobial materials through doping rare-earth elements is a new strategy to overcome this challenge. To this end, we design antibacterial films containing CeO2-x-TiO2, xanthan gum, poly(acrylic acid), and hyaluronic acid. CeO2-x-TiO2 inks are additionally integrated into a hexagonal grid for prominent transparency. Such design yields not only an antibacterial efficacy of ∼100% toward Staphylococcus aureus and Escherichia coli but also excellent antifog performance for 72 h in a 100% humidity atmosphere. Moreover, FluidFM is employed to understand the interaction in-depth between bacteria and materials. We further reveal that reactive oxygen species (ROS) are crucial for the bactericidal activity of E. coli through fluorescent spectroscopic analysis and SEM imaging. We meanwhile confirm that Ce3+ ions are involved in the stripping phosphate groups, damaging the cell membrane of S. aureus. Therefore, the hexagonal mesh and xanthan-gum cross-linking chains act as a reservoir for ROS and Ce3+ ions, realizing a long-lasting antibacterial function. We hence develop an antibacterial and antifog dual-functional material that has the potential for a broad application in display devices, medical devices, food packaging, and wearable electronics.