A comprehensive study was conducted to investigate the formation of highly porous, fluffy TiO2 nanocoatings on carbon nanofibers (CNFs) using the condensed layer deposition (CLD) process with surface hydrolysis. Partial hydrolysis and polymerization of titanium tetra-isopropoxide (TTIP) was attributed to forming a fluffy coating morphology. Unreacted alkyl ligands retained inside the metal oxide-alkoxide matrix led to a cross-linking polymeric structure. It was demonstrated in Fourier-transform infrared that the content of the confined organic ligands from the TTIP precursor decreased as the water to the chemical precursor ratio increased, indicative of an additional supply of protons that protonate the organic ligands. The released isopropoxide was analyzed with gas chromatography-mass spectroscopy. It was revealed that the ligands desorbed into the heptane solvent during the CLD process increased as the water amount was increased. Thermogravimetric analysis further confirmed reduction in the amount of organic residues with an increase in water content. Electron microscopy imaging showed a different morphology in the TiO2 coatings with different water ratios at a constant TTIP loading, in which the high amount of water increased the fluffiness of the coating. However, unlike TTIP, titanium ethoxide as a precursor led to a dense and smooth nanocoating on the CNFs, which was attributed to its four-metal center molecular structures.

Despite the exceptional optical properties of CsPbBr3 (CPB) nanocrystals (NCs), maintaining their long-term colloidal and structural reliability remains a significant barrier to commercialization. The influence of environmental conditions on Ostwald ripening and its effects on the crystal structure and optical behavior of CPB NCs has not been thoroughly investigated. In this work, CPB NCs were synthesized using a high-temperature hot-injection method and dispersed in n-heptane. They were evaluated by integrating population balance theory-based crystallization kinetic studies with experimental measurements over 30 days at aging temperatures of -20, 25, and 70 °C, which represent different storage conditions. The size and crystal lattice of CPB NCs dispersed in n-heptane are influenced by the aging time and temperature, which affect their UV absorbance and photoluminescence spectra. At -20 °C, the NC solutions retained their greenish fluorescence with negligible changes because of the limited crystal growth rate based on population balance kinetic models. However, increasing aging temperatures resulted in an increased crystal growth rate, with significant yellowing observed at 70 °C. Transmission Electron Microscopy, X-ray diffraction, and 3D-tomography studies confirmed that the CPB NCs exhibited 2D crystal growth, which accelerated with increased aging temperature. These findings highlight the nature of thermal degradation mechanisms in CPB NCs as a function of the long-term storage temperature and provide a framework for mitigating such issues.

Platinum catalysts degrade through dissolution and growth in electrocatalytic reactions. This work attempted to make a protection nanocoating of porous niobium oxide (NbOx) on Pt supported on carbon black (Pt/C), or Pt/C@NbOx, using the condensed layer deposition (CLD) technique. It was found that nanocoating thicknesses have a significant effect on the catalyst durability. The best catalyst was found to have a 29 wt% NbOx loading, corresponding to ca. 1.5 nm nanocoating thickness on the Pt/C catalyst. It was further found that thermal annealing critically influenced the catalyst performances. The Pt/C@NbOx catalyst annealed at 400 degrees C retained amorphous NbOx, while that annealed at 600 degrees C formed crystalline structures of NbOx. Electronic interactions between Pt and the crystalline NbOx were evidenced by Pt 4 f core electron binding energy shifting positively and Nb 3 d core electron shifting negatively. Accelerated stress tests for up to 30,000 cycles showed 16.5% increase in the electrochemical surface area (ECSA) of Pt/C@NbOx annealed at 600 degrees C, in contrast to a 49.8% loss in ECSA of Pt/C. More significantly, the loss in half-wave potential in oxygen reduction reaction is close to zero. This remarkably enhanced catalyst durability is attributed to the protection effect from the porous NbOx nanocoatings.

Polycrystalline solid-state ionic conductors (PolySSICs) are key energy materials for all-solid-state Li-ion batteries (LIBs). However, achieving room-temperature ionic conductivity comparable to that of liquid electrolytes (σ∼ 10^-2-10 S· cm^-1) remains a major challenge. Here, we experimentally demonstrate that thermal neutron irradiation provides an effective strategy for engineering ion transport in a model PolySSIC, LiBO_2, a promising electrode coating material for LIBs. High-flux (∼ 10^9 neutrons·cm^-2·s^-1) thermal neutrons (∼ 25 meV), delivered at Beam Port E of the University of Missouri Research Reactor (MURR), selectively transmute the strong neutron absorbers ^10B and ^6Li at their natural abundances (∼19.9% and ∼7.5%). This process generates lattice vacancies within polycrystalline grains while preserving long-range crystallographic order. In addition, γ photons produced during ^10B transmutation release electrons that suppress atomic displacement and partially neutralize the space charge associated with positively charged oxygen vacancies at grain boundaries. As a result, the ionic conductivity increases by nearly 20% in grains and more than 80% at grain boundaries. These results validate theoretical predictions and demonstrate a controllable strategy for enhancing ion transport in PolySSICs for solid ionic devices, including LIBs.

LiBO2 is an electronic insulator and a promising multi-functional material, notably as an effective surface coating for stabilizing high-voltage cathodes in lithium-ion batteries. Despite its potential, the underlying mechanisms of lithium-ion and electron transports in the presence of lattice vacancies remain inadequately understood. This is particularly important as such lattice vacancies may either facilitate or impede charge transport. A detailed understanding of these mechanisms is essential for the rational design and optimization of LiBO2-based materials. In our previous work [C. Ziemke, H. M. Nguyen, S. Amaya-Roncancio, J. Gahl, Y. Xing, T. W. Heitmann and C. Wexler, Formation of Lattice Vacancies and Their Effects on Li-ion Transport in LiBO2 Crystals: A Comparative ab initio Study, J. Mater. Chem. A, 2025, 13, 3146-3162], we used density functional theory (DFT) calculations to investigate the impact of lattice vacancies on Li-ion transport in both tetragonal (t-LBO) and monoclinic (m-LBO) polymorphs of LiBO2, revealing that B vacancies in either polymorph enhanced lithium-ion transport. In contrast, in this study we used DFT calculations to examine the effects of lattice vacancies on the electronic properties of both t-LBO and m-LBO polymorphs, focusing on the electronic band structure. Our analysis shows that B vacancies can enhance the electronic insulation of t-LBO while improving the electronic conduction of m-LBO. This finding reveals a strongly polymorph-dependent material selection, specifically the generation of B vacancies in LiBO2 may enable t-LBO to function as a promising solid electrolyte (i.e., both a good ionic conductor and a good electronic insulator) and enhance the performance of m-LBO as a conformal cathode coating (i.e., both a good ionic conductor and a good electronic conductor) in lithium-ion batteries. Therefore, generating B vacancies, such as by neutron irradiation, would offer a viable strategy to improve the functionality of LiBO2 as a promising material for energy storage applications. Overall, while focusing mainly on electron transport, this study complements our earlier work on ion transport and establishes a foundational understanding for future investigations of crucial aspects of LiBO2, such as electrochemical stability, mechanical robustness, and interfacial behavior.

Solar-driven interfacial evaporation (SDIE) technology represents a promising solution for freshwater harvesting, characterized by its cost-effectiveness, eco-friendliness, and sustainability. Nevertheless, achieving efficient removal of heavy metal ions during the SDIE process remains a significant challenge. In this study, we present a cost-effective method to construct a hybrid hydrogel evaporator by incorporating the konjac glucomannan (KGM) and reduced graphene oxide (rGO) into a polyvinyl alcohol (PVA) network. The hybrid hydrogel evaporator features a three dimensional layered structure, full spectrum absorption capability, high stability and inherent salt diffusion ability. These characteristics enabling an evaporation rate of 1.61 kg m- 2 h- 1 from wastewater across varying pH values (2-12) and high salinity levels (1 kW m- 2 ). Significantly, the hybrid polymer network within the hydrogel is rich in-OH groups, enabling concurrent wipe off heavy metal ions and organic dyes from wastewater. The results in a ten thousand times reduction in the concentration of heavy metals such as Cr3+, Mn2+, Cu2+, Zn2+, and Pb2+ in the wastewater. This study provides new insights into solar evaporation technology and contributes to addressing challenges related to water scarcity.

Development of durable Pt-based catalysts for oxygen reduction reaction (ORR) is crucial for the commercial success of fuel cells in heavy-duty vehicle applications. Here, a facile deposition technique of ultra-thin ZrO2 layers onto the surface of Vulcan XC72 carbon black (CB) was achieved through the condensed layer deposition technique. The follow-on deposition of Pt nanoparticles was achieved by ethylene glycol reduction of potassium tetrachloroplatinate. It was found that the Pt nanoparticles formed elongated shapes, following that of the ZrO2 on the carbon surface, consistent with strong interfacial anchoring effect between Pt and ZrO2. Electrochemical tests showed that the Pt/ZrO2/CB catalyst has excellent electrochemical activity and durability in perchloric acids. After 10,000 cycles between 0.6 and 1.1 VRHE in 0.1 M perchloric acid, there was only ca. 10 mV loss in the half-wave potential in ORR. However, the morphology of the Pt nanoparticles changed to near spherical shapes after cycling, with a slight (1.3%) increase in the electrochemical surface area as compared to the large decrease (33.5%) in the Pt/C catalyst without ZrO2 anchoring. It was also found that the ORR mass activity decreased by 17.8%, much better than the 37.5% decrease in Pt/C.

Coupling Pt with metal oxides has been shown to be an effective approach for catalyst durability enhancement in the methanol oxidation reaction (MOR). Here, we report tuning valence in niobium oxide (NbOx) as a support by tin oxide (SnO2) as a promoter to mediate the Pt electrocatalysis in MOR. The catalyst was designed to consist of Pt supported on SnO2-modified NbOx coated on carbon black (Pt-TNb/C), which shows significantly enhanced electrochemical durability and activity in MOR that are better than the catalyst without SnO2 modification (Pt-Nb/C) and those reported in the literature. Electron diffraction pair distribution function analysis showed an increase in the Nb-Nb bond length after SnO2 incorporation, from 3.80 to 3.84 & Aring;, indicative of a tuning effect. X-ray photoelectron spectroscopy further confirmed valence mediation in the Pt-TNb/C catalyst, as evidenced by the positive binding energy peak shifts of 0.49 and 0.66 eV in Nb 3d5/2 and Nb 3d3/2, respectively, as compared to those of the Pt-Nb/C catalyst. The Pt-Nb/C catalyst has MOR peak currents of 2.71 A/mg-Pt at the beginning and 1.94 A/mg-Pt at the end of 1000 cycles in 1.0 M methanol in 0.5 M H2SO4 electrolyte, corresponding to a 28.41% activity loss. However, the Pt-TNb/C catalyst with SnO2 tuning has a much smaller loss at only 3.77%, with MOR peak currents of 3.45 A/mg of Pt at the beginning and 3.32 A/mg of Pt at the end under the same test conditions. The high durability and activity of the new catalyst are attributed to the effect of valence tuning of the niobium oxide, in addition to a bifunctional effect from tin oxide.

The monoclinic (m-LBO) and tetragonal (t-LBO) polymorphs of LiBO2 have significant potential for applications such as solid electrolytes and electrode coatings of lithium-ion batteries. While comparative experimental studies of electron and lithium transport in these polymorphs exist, the role of lattice vacancies on lithium transport remains unclear. In this study, we employed density functional theory (DFT) to investigate the impact of boron and oxygen vacancies on the lattice structure, electronic properties, and lithium migration energy barrier (Em) in m-LBO and t-LBO. Our DFT results reveal that boron and oxygen vacancies affect lithium transport in both the polymorphs, but in different ways. While oxygen vacancies lower Em in m-LBO, they increases Em in t-LBO. In contrast, boron vacancies significantly reduce Em in both m-LBO and t-LBO, leading to enhanced diffusivity and ionic conductivity in both polymorphs. This improvement suggests a potential strategy for improving ionic conductivity in LiBO2 through boron vacancy generation.

LiBO_2 is an electronic insulator and a promising surface coating for stabilizing high-voltage cathodes in lithium-ion batteries. Despite its potential, the functional mechanisms of this coating remain unclear, particularly the transport of lithium ions and electrons through LiBO_2 in the presence of lattice vacancies. This understanding is critical for the design and development of LiBO_2-based materials. In our previous work [Ziemke et al., J. Mater. Chem. A, 2025, 13, 3146-3162], we used density functional theory (DFT) calculations to investigate the impact of lattice vacancies on Li-ion transport in both tetragonal (t-LBO) and monoclinic (m-LBO) polymorphs of LiBO_2, revealing that B vacancies in either polymorph enhanced lithium-ion transport. In this study, we expand on these findings by using DFT calculations to examine the effects of lattice vacancies on the electronic properties of both t-LBO and m-LBO polymorphs,focusing on the electronic band structure. Our analysis shows that B vacancies can enhance the electronic insulation of t-LBO while improving the ionic conduction of m-LBO. The combined results of our previous and current works indicate that B vacancy generation in LiBO_2 may enable t-LBO to function as a promising solid electrolyte and enhance the performance of m-LBO as a conformal cathode coating in lithium-ion batteries. Overall, generating B vacancies, such as through neutron irradiation, would offer a viable strategy to improve the functionality of LiBO_2 as a promising material for energy storage applications.

A novel approach to the fabrication of thin-film supported metal oxide membranes was investigated. Nanocoatings were obtained by the condensed layer deposition of TiO2 on tubular microporous supports, applying multiple consecutive layers of TiO2/polyaniline. The surface, cross-sectional structure, and morphology of the materials were investigated by electron microscopy. Their membrane-related properties were explored by permeability measurements, rejection, and fouling analysis, using polyethylene glycol (PEG) as test molecules. The SEM images showed that TiO2 was successfully deposited on the surface, creating a layer with partial coverage of the support after each layer was deposited; consequently, the permeability of the membranes decreased gradually. Overall, the results of the flux and permeability of the membranes confirmed the coating. The transmembrane pressure (TMP) increased with each coating layer, while the rejection of the membrane showed gradual improvement.

Platinum-based catalysts show high activity for the oxygen reduction reaction (ORR) in Proton Exchange Membrane (PEM) fuel cells. However, platinum nanoparticles (Pt NPs) are prone to dissolution and agglomeration in the high potential, temperature, and acidic environment of the PEM fuel cell cathode. In this work, Pt/C was coated by ~2.5 nm nanoporous niobium oxide to stabilize the Pt NPs, denoted NbOx@Pt/C. The coated catalysts were annealed at 400 and 600 °C. Compared to the bare Pt/C, X-ray diffraction data for NbOx@Pt/C-400 have shown no change in crystallinity whereas NbOx@Pt/C-600 has shown NbOx phase transition from amorphous to crystalline. X-ray photo spectroscopy (XPS) characterization has shown a positive binding energy shift in Pt 4f and a negative binding energy shift in Nb 3d in NbOx@Pt/C-600 as compared to that of NbOx@Pt/C-400 or Pt/C. The NbOx@Pt/C-600 catalyst shows underpotentially hydrogen adsorption indicating possible proton transport in the niobium oxide layer, but less slightly ORR activity compared to pure Pt/C. Hypothetically, this could be due to the facile diffusion of protons through the porous metal oxide coating compared to the dissolved oxygen gas that has larger molecular sizes. Nonetheless, NbOx@Pt/C-600 has shown a close to zero loss in ECSA after 30K cycles in durability test whereas Pt/C has a loss of ~30%. The high stability is attributed to the NbOx layer that protects Pt NPs from corrosion and degradation. This work demonstrated an approach that is a step forward in designing a durable catalyst for ORR in PEM fuel cells. Keywords: Pt catalysts, Niobium Oxides, Durability, Nanoporous coating

Oily wastewater is produced from many processes in petrochemical, food, pharmaceutical, mining, and metal industries. Proper management of oily wastewater discharges is required to mitigate their environmental impacts. Basalt fabric has been reported as being uniquely suitable for oily wastewater purification via solar evaporation due to its robust structure and surface chemistry. In this study, an efficient, low-cost, and scalable 3D photothermal evaporator was prepared by surface modification of basalt fabric with TiO2 nanoparticles for oily wastewater treatment and solar steam generation. The basalt membrane was coated with two types of TiO2 (Degussa P25 and nitrogen-doped TiO2) to enhance its hydrophilicity and photocatalytic properties important for fouling control. The basalt membranes were then tested for their impacts on water evaporation under various salinities and concentrations of gasoline constituents and crude oil. In pure water, the modified membrane system achieved an evaporation rate of 1.65 kg ‧m(-2)‧h(-1) under 1 sun irradiation, which is higher than the theoretical value of 1.47 kg ‧m(-2)‧h(-1) due to the 3D nature of the structure capable of harvesting energy from the environment. Crude oil significantly decreased the evaporation rate of the unmodified basalt membrane. However, the coating of TiO2 nanoparticles was found to ameliorate the fouling effect by increasing the membrane evaporation efficiency from 0.75 kg ‧m(-2)‧h(-1) to 1.42 kg ‧m(-2)‧h(-1) in a 2.0 g/L oily water composition. This technology is promising as a new approach to manage oily wastewater storage tanks and evaporation ponds in industry in addition to improving the efficiency of resource recovery.

Commercially available solutions of polyaniline (PANI) stabilized with dinonylnaphthalene sulfonic acid (DNNSA) offer a convenient means of forming PANI films via solution casting that are of interest for energy storage and other electrochemical applications. Here, we study the electrochemical charge storage properties of 200–400 nm thick PANI films cast from PANI-DNNSA solutions before and after postprocessing steps. As-cast PANI-DNNSA films exhibit a specific capacitance of <20 F/g at a 50 mV/s sweep rate, which increases to >300 F/g after p-toluene sulfonic acid:butanol (pTSA:BuOH) and dibromopropane (PrBr2) treatments. Crosslinked PANI also exhibits a 25% improvement in capacity retention over un-crosslinked PANI after 500 charge/discharge cycles. The capacity, energy, and power of postprocessed PANI films is examined in a symmetric coin cell device, and the utility of soluble PANI is demonstrated by coating planar and porous substrates using spin coating, drop casting, and dip coating techniques. These studies inform the use of PANI-DNNSA to fabricate high-capacity electrochemical devices.

Hydrogen peroxide is considered a highly powerful oxidant and can oxidize thiophene contaminant compounds in diesel. In this work, a trickle bed electrochemical reactor (TBER) with multiple cells is investigated for diesel desulfurization, which is intensified with a highly effective electrocatalyst, MnO2, for in situ hydrogen peroxide production. The multiple cell TBER demonstrates much enhanced oxidation of dibenzothiophene (DBT) in diesel flowing with alkaline electrolyte through the TBER. A 500 ppm DBT was completely oxidized in situ in the multi-cell TBER in 2.5 h, indicative of highly efficient deep desulfurization of diesel fuel within the multi-cell TBER.

Aluminosilicate zeolite nanoparticles were synthesized in a water-in-oil solvent and applied as an adsorbent for tetracycline (TC) removal from aqueous solutions. The large specific surface area at 495.8 m2 g-1 confirms that the zeolite nanoparticles have mesopores. The zeolite nanoparticles show an excellent removal efficiency for TC, achieving over 97% in the pH range of 4.70-7.17. A fast adsorption kinetics was observed, reaching equilibrium in only 20 min following a pseudo-second-order kinetic model. The adsorption isotherm was found to follow the Langmuir model, with a maximum adsorption capacity of TC of 454.55 mg g-1 at pH 6.7 with no salt added. After 6 cycles of reuse, the removal efficiency of TC remained high at 90.3%. It was understood that the adsorption process is spontaneous and exothermic, with an activation energy of 37.94 kJ mol-1. The high observed adsorption affinity is attributed to hydrogen bonding between TC and the hydroxyl groups on the zeolite nanoparticles and the formation of outer-sphere surface complexes. This study shows a new way to synthesize aluminosilicate zeolite nanoparticles that are an efficient and recyclable adsorbent for effective removal of TC from contaminated water.

Polyaniline (PANI) is a charged polymer well-known for its high charge storage capacity and moderate electrical conductivity. PANI is often prepared by chemical or electro-polymerization, however, these polymerization methods limit options for substrate material, electrode/device geometry, and polymer morphology. To address these limitations, it is attractive to form PANI films by solution-casting. In this study, we examine the electrochemical properties of solution-cast PANI films formed from a commercially available PANI suspension containing excess dinonylnaphthalenesulfonic acid (DNNSA). Films prepared by solution casting of PANI-DNNSA have been previously characterized in terms of conductivity, morphology, and optical properties, however the electrochemical behavior of these films has been largely unexplored. Here, we present an electrochemical analysis of these solution-cast PANI films using quartz crystal microbalance, electrochemical impedance spectroscopy, and cyclic voltammetry. As cast, we find that the polymer exhibits limited electrochemical activity, but that postprocessing the material with electrolyte and crosslinking solutions increases the charge capacity up to 95 mAh/g – 86% of the charge capacity typically reported for electrodeposited PANI films. Ion-exchange processes, electrochemical capacitance, and energy storage capabilities of the chemically treated solution-cast films are assessed and compared to those of electro-deposited and chemically oxidized PANI. We demonstrate redox-active PANI films on both (a) conductive and insulating, and (b) planar and porous substrates. Finally, symmetric faradaic supercapacitor devices were constructed using spin-coated PANI electrodes in aqueous electrolyte, and the stability of these devices was examined by repeat galvanostatic charging/discharging at low current, achieving up to 88% capacity retention after 500 charge-discharge cycles.

This study evaluated the effect of carbon nanofibers (CNFs) coated by aluminum oxide Al2O3 as a reinforcement on compressive strength, frost resistance, and drying shrinkage of cement mortars. Three weight ratios of 0.125%, 0.25%, and 0.5% of Al2O3/CNFs and bare CNF cement mortars were compared with reference cement mortar samples. The reactive porous and high surface area layer of alumina induced the hydration reaction and promoted the production of well-distributed hydration gel. Derivative thermal analysis–differential thermogravimetric (TGA-DTG) and X-ray powder diffraction (XRD) characterization showed that Al2O3/CNFs reinforcement led to greater hydration gel production than bare CNFs. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were performed to study the coating and microstructure of the cement mortars evaluated in this paper. The results show that the optimum enhancement of the cement mortar properties was obtained at ratios of 0.125% for Al2O3/CNFs and 0.25% for CNFs. This enhancement was greater with Al2O3/CNFs-reinforced specimens in terms of high compressive strength, less compressive strength degradation after 150 cycles, and less drying shrinkage. The low use of the CNFs in Al2O3/CNFs samples indicates the coating is an economical and promising approach for improving the performance of cement mortars.

Two different types of cathode materials were prepared using glycerol as a solvent and reactant. The LiMn1/3Ni1/3Co1/3O2 layered oxide cathode material was successfully synthesized with a shorter time of heat treatment of 8hr at 900°C. An appreciated capacity retention of 83.7% after 100 cycles with an initial discharge capacity of 177.1 mAh/g at 0.1C (discharge rate) has been achieved. Another cathode material with the formula of Li1.2 Mn0.51Ni0.145+xCo0.145-xO2 (x=0 (LR2), 0.0725 (LR1)), as a Li-rich cathode material, has been also successfully synthesized using glycerol. It was shown that LR1 discharge capacity was increased from 185 to 213 mAh/g after 20 cycles and ended up with 194.9 mAh/g after 60 cycles at 0.1C (discharge rate). This material shows an exceptional discharge capacity retention, lower toxic cobalt component, and lower production cost comparing with other Li-rich cathode materials. Detailed results of powder material synthesis, characterization, and battery testing will be presented to demonstrate that glycerol as a green solvent in the synthesis of battery materials.

The overall objective of this project was to develop an advanced manufacturing technology for Li-ion battery materials production at low cost and in a green chemical process using glycerol as solvent to replace water. It was aimed at developing a prototype pilot production line to reduce production cost by at least 25% to the baseline. During the course of this project, research was conducted to understand spray drying and combustion of eutectic solvent precursors of glycerol and metal salts (acetates) in the formation of mixed metal oxide powders. Reactor design and optimization were done to facilitate spray drying and combustion in powder formation and processing. Various cathode materials powders were produced, including lithium nickel-cobalt-manganese oxide (NCM) and lithium nickel-cobalt-aluminum oxide (NCA). These cathode materials powders were tested in half coin cells for their performances, with materials performances of 160 mAh/g for NCM111 and 200 mAh/g for NCA. NCA powders were also produced using a slurry spray-drying process and tested in full pouch cells. A pilot scale flame assisted spray drying reactor was constructed and demonstrated for its production rate exceeding the target of production rate of four metric tons per year. The work performed in this project has been documented in 9 peer reviewed journal publications, 8 conference presentations, and two IP disclosures/patent applications.