The Journal of Physical Chemistry C最新文献

{"title":"Magnetically Tunable Refractive Indices of Fe3O4–Polydimethylsiloxane Composite Films","authors":"Qiushu Zhang,&nbsp;, ,&nbsp;Gezhe Li,&nbsp;, ,&nbsp;Pan Wen,&nbsp;, ,&nbsp;Xinyue Wang,&nbsp;, and ,&nbsp;Bei Peng*,&nbsp;","doi":"10.1021/acs.jpcc.4c07080","DOIUrl":"10.1021/acs.jpcc.4c07080","url":null,"abstract":"<p >As a promising smart material, magnetorheological elastomer (MRE) is mainly investigated for its mechanical properties. This study presents the results on MRE’s optical property. The MRE films, i.e., the composite films made of polydimethylsiloxane (PDMS) embedded with 0.5–2.5 wt % Fe₃O₄ nanofillers, were spin-cast onto Si substrates from mixture solutions that were prepared via toluene dilution, mechanical stirring, ultrasonic agitation, and vortex mixing. There are two components in the obtained films, namely, the opaque micron-sized Fe₃O₄ clusters and the homogeneous transparent host medium consisting of PDMS and nanosized Fe₃O₄ particles. The film’s refractive indices were measured using an ellipsometer under an external magnetic field of <i>B</i> = 0, 55, 100, 135, and 180 mT. The experimental results indicate that subjection to a magnetic field can remarkably affect the film’s refractive indices. For the film containing 2.5 wt % Fe₃O₄, the refractive index increases to 2.127 when applying a magnetic field of <i>B</i> = 55 mT, while the refractive index is only 1.666 in the absence of a magnetic field. It is believed that the magnetically tunable refractive indices of the composite films result from the film’s magnetostrictive stresses, which change the nanoparticle concentration in the transparent film host mediums and the dielectric constant of PDMS. As the refractive index could be changed via imposing a magnetic field, the composite films under investigation might find applications in optical microelectromechanical systems and intelligent optical elements.</p>","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"129 41","pages":"18606–18615"},"PeriodicalIF":3.2,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145229278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of the Purification Strategy on the Activity and Stability of FeNC Catalysts for the Oxygen Reduction Reaction","authors":"Nicole Segura-Salas,&nbsp;, ,&nbsp;Vladislav Gridin,&nbsp;, ,&nbsp;Viktoriia A. Saveleva,&nbsp;, ,&nbsp;Pascal Theis,&nbsp;, ,&nbsp;Steffen Haller,&nbsp;, ,&nbsp;Vinod K. Paidi,&nbsp;, ,&nbsp;Hendrik Haak,&nbsp;, ,&nbsp;Lanjie Jiang,&nbsp;, ,&nbsp;Blanka Detlefs,&nbsp;, ,&nbsp;Vasily Potapkin,&nbsp;, ,&nbsp;Kathrin Hofmann,&nbsp;, and ,&nbsp;Ulrike I. Kramm*,&nbsp;","doi":"10.1021/acs.jpcc.5c04548","DOIUrl":"10.1021/acs.jpcc.5c04548","url":null,"abstract":"<p >FeNC materials are a promising alternative to substitute platinum catalysts in proton exchange membrane fuel cells (PEMFCs) for electrocatalysis of the oxygen reduction reaction (ORR). However, it remains an active research challenge to improve their stability, based on the interconnection of the multiple degradation mechanisms such as carbon corrosion, active site (FeN₄) demetalation, decrease of hydrophobicity, etc. In this study, we compare the impact of different purification strategies involving ball milling and forming gas (N₂/H₂) heat treatment followed by acid leaching designed to remove efficiently the remaining Fe-inorganic species after pyrolysis, which may promote the degradation of the catalyst and membrane during FC tests. Through a comprehensive structural characterization of the final composition by X-ray diffraction, X-ray absorption, and X-ray emission spectroscopies and carbon morphology (transmission electron microscopy and Raman spectroscopy) of the FeNCs, we achieved an efficient removal of Fe₃C species, accompanied by distinct alterations to the carbon morphology, which prove to be crucial for the material’s stability. Our results highlight the enhanced stability of the catalyst treated under N₂/H_2, which retained 82% of its initial current density while held at 0.5 V for 24 h in H₂/Air during FC testing. With this study, we prove the importance of FeNC catalyst’s purification and its benefit in fuel cell activity and stability.</p>","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"129 41","pages":"18439–18450"},"PeriodicalIF":3.2,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145229281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Graphene Straintronics by Molecular Trapping","authors":"Pawan Kumar Srivastava,&nbsp;, ,&nbsp;Vedanki Khandelwal,&nbsp;, ,&nbsp;Indukuru Ramesh Reddy,&nbsp;, ,&nbsp;Kartick Tarafder,&nbsp;, and ,&nbsp;Subhasis Ghosh*,&nbsp;","doi":"10.1021/acs.jpcc.5c04013","DOIUrl":"10.1021/acs.jpcc.5c04013","url":null,"abstract":"<p >Here, we report on controlling strain in graphene by trapping molecules at the graphene–substrate interface and leveraging molecular dipole moments. Spectroscopic and transport measurements reveal that strain correlates with the dipole moments of trapped molecules extending beyond their molecular sizes, where values ranging from 1.5 to 4.9D lead to a 50-fold increase in strain and a significant rise in residual carrier density. This has been possible by charge transfer between graphene and trapped molecules, altering the C═C bond length and causing biaxial strain. First-principles density functional theory calculations confirm a consistent dependence of the bending height on molecular dipole moments.</p>","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"129 41","pages":"18530–18536"},"PeriodicalIF":3.2,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145236060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Role of DFT Calculations in μ+SR Studies of Battery Materials","authors":"Hiroto Ohta*,&nbsp; and ,&nbsp;Jun Sugiyama*,&nbsp;","doi":"10.1021/acs.jpcc.5c03880","DOIUrl":"10.1021/acs.jpcc.5c03880","url":null,"abstract":"<p >Internal nuclear magnetic fields in various battery materials have been predicted using density functional theory (DFT) calculations to interpret the μ⁺SR results, particularly for identifying the diffusing species responsible for the dynamic behavior observed. In materials where Li⁺ and Na⁺ ions are mobile, these cations readily change positions to minimize electrostatic repulsion with the implanted μ⁺. As a result, the μ⁺ sits at the bottom of a deep potential well, stabilizing itself through a “self-trapping″ effect, making it a stable observer for detecting ion diffusion in battery materials. In contrast, in many metals and oxides, the implanted μ⁺ diffuses even at low temperatures. In these materials, the local lattice distortion caused by the implanted μ⁺ is relatively small compared to that in battery materials. To assess the stability of the implanted μ⁺, we propose a ratio between the measured nuclear magnetic field distribution width (Δ^exp) and the DFT-predicted value without lattice relaxation (Δ^min), namely, Δ^exp/Δ^min, as an indicator of whether cations or μ⁺ are diffusing. This indicator provides a comprehensive understanding of the diffusive behavior detected with μ⁺SR in various materials, including battery materials, metals, and other oxides.</p>","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"129 41","pages":"18406–18416"},"PeriodicalIF":3.2,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145229280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Defects in Al-Doped ZnO in Reactions with CO2 and H2: An In Situ/Operando cw ESR-Study","authors":"Zohreh Asadi,&nbsp;, ,&nbsp;Peter Ziems,&nbsp;, ,&nbsp;Clara Patricia Marshall,&nbsp;, ,&nbsp;Daniel Delgado,&nbsp;, ,&nbsp;Ralf Feyerherm,&nbsp;, ,&nbsp;Frank Girgsdies,&nbsp;, ,&nbsp;Wiebke Riedel,&nbsp;, ,&nbsp;Christian Teutloff,&nbsp;, ,&nbsp;Annette Trunschke,&nbsp;, and ,&nbsp;Thomas Risse*,&nbsp;","doi":"10.1021/acs.jpcc.5c05786","DOIUrl":"10.1021/acs.jpcc.5c05786","url":null,"abstract":"<p >In this study, Al-doped ZnO (AZO) is investigated by combining in situ and operando continuous wave (cw) electron spin resonance (ESR) measurements with other methods, including microwave cavity perturbation technique (MCPT), magnetization, TGA, ²⁷Al-NMR, transmission electron microscopy, and XRD measurements. As Al-doped ZnO (AZO) is the support of Cu/ZnO:Al (CZA), an industrially used catalyst for methanol synthesis, studying the evolution of defects and changes in electronic structure under conditions used for reductive activation of the CZA catalyst or typical conditions for the r-WGS reaction is of interest to gain further insight into the complex interplay between the different components in the CZA catalyst. Next to paramagnetic defect sites, a ferromagnetic phase was observed forming upon activation in reducing atmospheres, which is modified, but not destroyed in (re)oxidizing conditions. The results prove the oxidizing effect of CO₂ on the paramagnetic defects as well as the ferromagnetic phase of an activated AZO. Comparison with prior results on CZA provides insight into the effect of Cu on AZO and enhances the understanding of the synergistic effects in the catalyst.</p>","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"129 41","pages":"18841–18854"},"PeriodicalIF":3.2,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/acs.jpcc.5c05786","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145229284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural Changes upon Ambient Temperature Densification in Calcium Aluminoborosilicate Glasses: Relation to Indentation Crack Resistance","authors":"Yara Hellen Firmo Gomes,&nbsp;, ,&nbsp;Gustavo A. Rosales-Sosa,&nbsp;, ,&nbsp;Shingo Nakane,&nbsp;, ,&nbsp;Yoshinari Kato,&nbsp;, ,&nbsp;Hiroki Yamazaki,&nbsp;, ,&nbsp;Akihiro Yamada,&nbsp;, and ,&nbsp;Hellmut Eckert*,&nbsp;","doi":"10.1021/acs.jpcc.5c04951","DOIUrl":"10.1021/acs.jpcc.5c04951","url":null,"abstract":"<p >Improving crack initiation resistance is an important objective of current glass research. High-pressure and indentation experiments are considered important predictors for the compositional design of glassy materials with optimized performances. For developing insights into the stress dissipation mechanisms, it is important to understand their structural aspects at the atomic level. In the present contribution, the structural consequences of ambient-temperature densification via pressurization at 25 GPa were studied by solid-state NMR and Raman spectroscopy for a series of calcium aluminoborosilicate glasses with composition (70–<i>x</i>)SiO₂–<i>x</i>B₂O₃–15Al₂O₃–15CaO (<i>x</i> = 0, 5, 15, 25). Cold pressurization resulted in a significant increase in the average coordination numbers of both boron and aluminum, in line with previous results found in hot-compressed alkali and alkaline-earth aluminoborosilicate glasses. Advanced ¹¹B/²⁷Al double resonance experiments suggest that B–O–Al connectivities play an important role in the structural transformation processes, contributing to the experimentally observed increase of indentation crack resistance with increasing B₂O₃ content. Our results indicate that the extent of densification is a poor predictor of indentation crack resistance and highlight the significance of medium-range order effects.</p>","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"129 41","pages":"18772–18783"},"PeriodicalIF":3.2,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145236013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to “Tuning Molecular Emission: Exploring Plasmonic Coupling Effects Across High and Low Quantum Yields”","authors":"Stavros Athanasiou*,&nbsp; and ,&nbsp;Olivier J. F. Martin*,&nbsp;","doi":"10.1021/acs.jpcc.5c06708","DOIUrl":"10.1021/acs.jpcc.5c06708","url":null,"abstract":"","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"129 41","pages":"18855"},"PeriodicalIF":3.2,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145236015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimizing Sputtered Iridium Electrocatalysts for Acidic Oxygen Evolution Using Design of Experiments","authors":"Joshua Adedeji Bolarin,&nbsp;, ,&nbsp;Gyan Prakash Sharma,&nbsp;, ,&nbsp;Chayanika Das,&nbsp;, ,&nbsp;Syed Mubeen,&nbsp;, and ,&nbsp;Nirala Singh*,&nbsp;","doi":"10.1021/acs.jpcc.5c03764","DOIUrl":"10.1021/acs.jpcc.5c03764","url":null,"abstract":"<p >Iridium is considered the most effective electrocatalyst for the oxygen evolution reaction (OER) in acidic media. Often, iridium is mixed with cocatalysts or support materials to boost the OER performance and reduce the cost of water electrolyzers. To synthesize efficient iridium electrocatalysts, many studies vary either one or more fabrication parameters at a time without evaluating the potential interactions between them, which could improve the electrocatalysts’ overall performance. In this study, we examine the combined effects of iridium thickness, titanium adhesion layer thickness, annealing temperature, and annealing time on the performance of sputtered iridium electrocatalysts in sulfuric acid (H₂SO₄) through a factorial design of experiments (DoE). The DoE response analysis of our electrochemical data through the main, interaction, and standardized effects plots, with added experimental optimization of results, enabled the identification of a sputtered titanium-supported iridium electrocatalyst that operated continuously for 48 h in 1 M H₂SO₄ at 1.61 V vs RHE for a 10 mA/cm² current density. Our study shows how statistical analysis through factorial DoE can be used as a tool to improve the activity and stability of OER electrocatalysts in acidic media.</p>","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"129 41","pages":"18391–18405"},"PeriodicalIF":3.2,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145229279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Deep Levels in Iron-Doped Gallium Oxides on Electron Transport","authors":"Qingming Huang,&nbsp;, ,&nbsp;Xinhang Cai,&nbsp;, ,&nbsp;Wenlong Yan,&nbsp;, ,&nbsp;Xiangyu Xu,&nbsp;, ,&nbsp;Wenjing Xu,&nbsp;, ,&nbsp;Duanyang Chen,&nbsp;, ,&nbsp;Kang Wang*,&nbsp;, ,&nbsp;Zhangqiang Yang*,&nbsp;, ,&nbsp;Hongji Qi,&nbsp;, ,&nbsp;Kelvin H. L. Zhang*,&nbsp;, and ,&nbsp;Ye Yang*,&nbsp;","doi":"10.1021/acs.jpcc.5c06121","DOIUrl":"10.1021/acs.jpcc.5c06121","url":null,"abstract":"<p >Iron-doped gallium oxide (Ga₂O₃) is extensively exploited as semi-insulating substrates for epitaxial thin film growth to fabricate next-generation high-power electronics and ultraviolet optoelectronics. However, the influence of iron (Fe) dopants on electron transport dynamics remains poorly understood, particularly in the context of defect-mediated scattering and trapping mechanisms. Here, we employ time-resolved terahertz (THz) spectroscopy to investigate the temperature-dependent photoconductivity and free electron dynamics in Fe-doped Ga₂O₃ crystals. The frequency-dependent THz conductivities demonstrate dispersive charge transport dominated by heterogeneous scattering, modeled effectively by the Drude–Smith formulizm. The temperature dependence of both electron mobility and electron scattering time indicates a transition from phonon-dominated scattering to a defect-mediated scattering mechanism. Moreover, the kinetics of transient photoconductivity further uncover that the free electrons collapse into a highly localized state fostered by Fe³⁺ dopants on a sub-100 ps timescale. Nevertheless, this trapping process is suppressed at low temperature because the itinerant electrons are trapped at the shallow defects before encountering deep centers associated with the Fe³⁺ dopant. Our results offer a fundamental understanding of the microscopic electron transport mechanism in Fe-doped Ga₂O₃ crystals.</p>","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"129 41","pages":"18600–18605"},"PeriodicalIF":3.2,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145229285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Entropy-Ruled Method on Density of States Proportion for Charge-Energy Transport in Organic Molecular Crystals: A Computational Study","authors":"Muthuvel Pavalamuthu,&nbsp; and ,&nbsp;Karuppuchamy Navamani*,&nbsp;","doi":"10.1021/acs.jpcc.5c04381","DOIUrl":"10.1021/acs.jpcc.5c04381","url":null,"abstract":"<p >The charge-energy transport mechanism in molecules is of fundamental importance and practical interest in the design of highly efficient molecular electronic devices. Importantly, the production of entropy due to charge dynamics-associated energy flux variation in the molecular solids causes nonequilibrium transport, and it leads to physics of deviation in Einstein’s diffusion-mobility relation of <i></i><math><mfrac><mi>D</mi><mi>μ</mi></mfrac><mo>=</mo><mfrac><mrow><msub><mi>k</mi><mi>B</mi></msub><mi>T</mi></mrow><mi>q</mi></mfrac></math> (Hurowitz, D.; Cohen, D., <i>Phys. Rev. E</i> <b>2014</b>, 90, No. 032129 and Navamani, K., <i>J. Phys. Chem. Lett.</i> <b>2025</b>, 16, 8596–8612). This urges the requirement of a suitable alternative method to attain better accuracy in semiconducting and optoelectronic properties in different molecular devices. With this motivation, the “density of states (DOS) proportion” is proposed to incorporate a band and nonadiabatic hopping transport mechanism at different thermodynamic conditions. The DOS proportion is in direct proportion with the population of electronic states or normal DOS. In this context, the developed <i>D</i>/μ relation and other extended charge transport (CT) formalism (conductivity, current density, etc.) are used to study the CT in dialkyl substituted dithienothiophene (<b>DSDTT</b>)-based molecular crystals. The CT key parameters such as charge transfer integral, site energy, and spatial overlap integral are computed from the dimer projection (DIPRO) method using electronic structure calculations. These CT key parameters, including reorganization energy, are used in the degeneracy-weighted diffusion equation and the DOS proportion factor to explore the CT in the <b>DSDTT</b>-based molecular derivatives. Using the entropy-ruled method under degenerate and large carrier energy flux approximation, the calculated hole mobility values are around 0.85 and 0.19 cm²/V s for <b>DSDTT-1</b> and <b>DSDTT-2</b> molecular crystals, respectively, reaching a proximity value with an experimentally obtained average mobility. From the obtained ideality factor from the quantum-corrected Shockley diode equation, Langevin transport (trap-free diffusion) is observed in these <b>DSDTT</b> molecules, which suggests that these molecules are good candidates for designing hole transporting (or P-type semiconducting) devices.</p>","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"129 41","pages":"18695–18714"},"PeriodicalIF":3.2,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}