Pub Date : 2026-01-27DOI: 10.1016/j.surfin.2026.108608
Ying Wang , Xinchun Tian , Shaotang Li , Chenyan An , Ling Liu , Yanbo Liu , Lihong Gao , Zhuang Ma
The expansion of flexible electronics has intensified the need for high-performance electrochromic films processable at low temperatures. While solution-based methods allow low-cost and large-area fabrication, their required high-temperature calcination step hinders compatibility with heat-sensitive substrates. To overcome this limitation, we employ non-thermal plasma (NTP) technology to achieve the room-temperature (35 °C) crystallization and surface activation of sol-gel derived TiO₂ films, entirely bypassing conventional high-temperature calcination. The resulting films exhibit an integrated combination of electrochromic properties, including a high coloration charge density, fast switching speed, and a large optical modulation of 37.6% at 550 nm, along with excellent cycling stability (31.4% modulation retention after 1000 cycles). This work presents NTP-assisted processing as a versatile, low-temperature route compatible with flexible substrates, laying a material and methodological foundation for the integration of high-performance oxide films into next-generation devices.
{"title":"Room-temperature fabrication of TiO2 thin films with enhanced electrochromic performance","authors":"Ying Wang , Xinchun Tian , Shaotang Li , Chenyan An , Ling Liu , Yanbo Liu , Lihong Gao , Zhuang Ma","doi":"10.1016/j.surfin.2026.108608","DOIUrl":"10.1016/j.surfin.2026.108608","url":null,"abstract":"<div><div>The expansion of flexible electronics has intensified the need for high-performance electrochromic films processable at low temperatures. While solution-based methods allow low-cost and large-area fabrication, their required high-temperature calcination step hinders compatibility with heat-sensitive substrates. To overcome this limitation, we employ non-thermal plasma (NTP) technology to achieve the room-temperature (35 °C) crystallization and surface activation of sol-gel derived TiO₂ films, entirely bypassing conventional high-temperature calcination. The resulting films exhibit an integrated combination of electrochromic properties, including a high coloration charge density, fast switching speed, and a large optical modulation of 37.6% at 550 nm, along with excellent cycling stability (31.4% modulation retention after 1000 cycles). This work presents NTP-assisted processing as a versatile, low-temperature route compatible with flexible substrates, laying a material and methodological foundation for the integration of high-performance oxide films into next-generation devices.</div></div>","PeriodicalId":22081,"journal":{"name":"Surfaces and Interfaces","volume":"84 ","pages":"Article 108608"},"PeriodicalIF":6.3,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1016/j.surfin.2026.108597
Lei Wang , Linglei Kong , Kaimin Xiao , Zhidong Liu , Weining Lei , Xudong Zhang
During wire electrical discharge machining (WEDM) of titanium alloys, the combined effects of localized high discharge temperatures and intricate electrochemical reactions facilitate the rapid formation of an oxide film on the machined surface. This oxide layer induces thin-film interference, leading to visible surface coloration that distinctly differs from the substrate's original appearance—a phenomenon referred to as titanium alloy coloration. To address this issue, an auxiliary electrode was introduced to mitigate the oxidation reaction by actively controlling the ionic interactions between the dielectric fluid and the workpiece. The suppression mechanism was examined through color difference measurements, scanning electron microscopy (SEM), and X-ray diffraction (XRD). Furthermore, single-factor experiments were conducted to systematically evaluate the effects of critical process parameters—auxiliary voltage, Auxiliary Distance (Distance between Auxiliary Electrode and Workpiece), and tracking frequency—on the material removal rate (MRR), surface roughness (Ra), and oxide layer thickness. Results indicate that the auxiliary electrode markedly reduces oxide thickness by directing the migration of ions within the dielectric, thereby producing a surface morphology that closely resembles the untreated substrate. This study validates the efficacy of the auxiliary electrode approach in minimizing surface coloration during WEDM and offers an experimental foundation for achieving non-coloring precision machining of titanium alloys.
{"title":"Experimental study on suppressing surface coloration in titanium alloy processed by wire electrical discharge machining using auxiliary electrode method","authors":"Lei Wang , Linglei Kong , Kaimin Xiao , Zhidong Liu , Weining Lei , Xudong Zhang","doi":"10.1016/j.surfin.2026.108597","DOIUrl":"10.1016/j.surfin.2026.108597","url":null,"abstract":"<div><div>During wire electrical discharge machining (WEDM) of titanium alloys, the combined effects of localized high discharge temperatures and intricate electrochemical reactions facilitate the rapid formation of an oxide film on the machined surface. This oxide layer induces thin-film interference, leading to visible surface coloration that distinctly differs from the substrate's original appearance—a phenomenon referred to as titanium alloy coloration. To address this issue, an auxiliary electrode was introduced to mitigate the oxidation reaction by actively controlling the ionic interactions between the dielectric fluid and the workpiece. The suppression mechanism was examined through color difference measurements, scanning electron microscopy (SEM), and X-ray diffraction (XRD). Furthermore, single-factor experiments were conducted to systematically evaluate the effects of critical process parameters—auxiliary voltage, Auxiliary Distance (Distance between Auxiliary Electrode and Workpiece), and tracking frequency—on the material removal rate (MRR), surface roughness (Ra), and oxide layer thickness. Results indicate that the auxiliary electrode markedly reduces oxide thickness by directing the migration of ions within the dielectric, thereby producing a surface morphology that closely resembles the untreated substrate. This study validates the efficacy of the auxiliary electrode approach in minimizing surface coloration during WEDM and offers an experimental foundation for achieving non-coloring precision machining of titanium alloys.</div></div>","PeriodicalId":22081,"journal":{"name":"Surfaces and Interfaces","volume":"84 ","pages":"Article 108597"},"PeriodicalIF":6.3,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, a total of 31 kinds of metal hydroxide powders (unary to quinary MOH) were prepared via the coprecipitation method using Fe, Co, Mn, Ni, and Ti as precursor ions. Subsequently, the corresponding composite electrodes (MOH@NF) were fabricated by coating the as-prepared MOH powders onto nickel foam (NF). Then through systematical investigation on the oxygen evolution reaction (OER) performance of the MOH@NF electrodes, two kinds of optimized composition were obtained: ternary FeCoMn hydroxide (t-MOH) and quinary FeCoMnNiTi hydroxide (f-MOH). Based on the compositions of t-MOH and f-MOH, a ternary FeCoMn alloy (t-MA) and a quinary FeCoMnNiTi alloy (f-MA) were prepared and then self-supported ternary and quinary metal oxide electrodes (t-MOx@t-MA and f-MOx@f-MA) were fabricated through anodization of the corresponding alloys. Electrochemical tests demonstrate that, compared with their MOH@NF counterparts, the η10 of t-MOx@t-MA and f-MOx@f-MA have decreased by 26 and 102 mV, respectively. Notably, f-MOx@f-MA has an ultralow OER overpotential of merely 185 mV and excellent stability. The proposed method with high efficiency and low cost is particularly suitable for application scenarios requiring large-scale catalyst screening.
{"title":"Influence of composition and preparation method on OER performance of multi-metal (hydro) oxide composite electrodes","authors":"Kai Lin, Xixin Wang, Mengyao Yang, Yaya Liu, Zihan Li, Jianling Zhao","doi":"10.1016/j.surfin.2026.108609","DOIUrl":"10.1016/j.surfin.2026.108609","url":null,"abstract":"<div><div>In this work, a total of 31 kinds of metal hydroxide powders (unary to quinary MOH) were prepared via the coprecipitation method using Fe, Co, Mn, Ni, and Ti as precursor ions. Subsequently, the corresponding composite electrodes (MOH@NF) were fabricated by coating the as-prepared MOH powders onto nickel foam (NF). Then through systematical investigation on the oxygen evolution reaction (OER) performance of the MOH@NF electrodes, two kinds of optimized composition were obtained: ternary FeCoMn hydroxide (t-MOH) and quinary FeCoMnNiTi hydroxide (f-MOH). Based on the compositions of t-MOH and f-MOH, a ternary FeCoMn alloy (t-MA) and a quinary FeCoMnNiTi alloy (f-MA) were prepared and then self-supported ternary and quinary metal oxide electrodes (t-MOx@t-MA and f-MOx@f-MA) were fabricated through anodization of the corresponding alloys. Electrochemical tests demonstrate that, compared with their MOH@NF counterparts, the η<sub>10</sub> of t-MOx@t-MA and f-MOx@f-MA have decreased by 26 and 102 mV, respectively. Notably, f-MOx@f-MA has an ultralow OER overpotential of merely 185 mV and excellent stability. The proposed method with high efficiency and low cost is particularly suitable for application scenarios requiring large-scale catalyst screening.</div></div>","PeriodicalId":22081,"journal":{"name":"Surfaces and Interfaces","volume":"84 ","pages":"Article 108609"},"PeriodicalIF":6.3,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-26DOI: 10.1016/j.surfin.2026.108612
Wei Yang , Zichenlu Wang , Fuwei Zhao , Lei Shi , Shifeng Deng , Jiaqi Pan , Wenzhen An , Yafeng Liu , Chaorong Li
A CuI/BiFeO3 quantum dots (QDs)/InGaZnO4 flexible transparent pn junction is prepared by the approach of sputtering-in situ iodization-sol-gel method. The CuI/BiFeO3 QDs/InGaZnO4 device achieves high transmittance of ∼80–85%, remarkable photoelectric enhancement of ∼3.7 × 103-folds to that of intrinsic CuI/InGaZnO4, good flexible stability of ∼89.7% in 1000 bending and stability in 6 months. The BiFeO3 QDs is considered as the core issue. Besides regulated Fermi level and high quantum yield, it owned charge inducing/injecting/driving can increase carrier dynamic to maintain the power conversion efficiency-transparency balance, includes hole inducing via Cu+/Cu2+. Additionally, the interfacial contact amelioration of CuI and interval filling of BiFeO3 QDs can improve flexible stability.
{"title":"Flexible transparent CuI/InGaZnO4 pn junction towards enhanced photoelectric conversion via interfacial perovskite BiFeO3 quantum dots potential transition and in situ iodization","authors":"Wei Yang , Zichenlu Wang , Fuwei Zhao , Lei Shi , Shifeng Deng , Jiaqi Pan , Wenzhen An , Yafeng Liu , Chaorong Li","doi":"10.1016/j.surfin.2026.108612","DOIUrl":"10.1016/j.surfin.2026.108612","url":null,"abstract":"<div><div>A CuI/BiFeO<sub>3</sub> quantum dots (QDs)/InGaZnO<sub>4</sub> flexible transparent pn junction is prepared by the approach of sputtering-<em>in situ</em> iodization-sol-gel method. The CuI/BiFeO<sub>3</sub> QDs/InGaZnO<sub>4</sub> device achieves high transmittance of ∼80–85%, remarkable photoelectric enhancement of ∼3.7 × 10<sup>3</sup>-folds to that of intrinsic CuI/InGaZnO<sub>4</sub>, good flexible stability of ∼89.7% in 1000 bending and stability in 6 months. The BiFeO<sub>3</sub> QDs is considered as the core issue. Besides regulated Fermi level and high quantum yield, it owned charge inducing/injecting/driving can increase carrier dynamic to maintain the power conversion efficiency-transparency balance, includes hole inducing <em>via</em> Cu<sup>+</sup>/Cu<sup>2+</sup>. Additionally, the interfacial contact amelioration of CuI and interval filling of BiFeO<sub>3</sub> QDs can improve flexible stability.</div></div>","PeriodicalId":22081,"journal":{"name":"Surfaces and Interfaces","volume":"84 ","pages":"Article 108612"},"PeriodicalIF":6.3,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-26DOI: 10.1016/j.surfin.2026.108596
Elizabeth Hermosillo-Arellano , Fidel Martínez-Gutiérrez , Roberto Leyva-Ramos , Erik César Herrera-Hernández , Ignacio René Galindo-Esquivel , René Darío Peralta-Rodríguez , Abraham Aram López-Cano , Esmeralda Mendoza-Mendoza
Novel green heterostructures of Ag2O/BiVO4 were prepared by a straightforward aqueous precipitation-hydrothermal route at different ratios of Ag2O (3, 6, and 10 wt %). Ag2O/BiVO4 heterostructures have scarcely been tested for ciprofloxacin (CIP) photodegradation under blue LED and sunlight exposure. Among the as-synthesized, the 10% Ag2O/BiVO4 delivered the highest performance within 360 min, degrading 85% of CIP (%XCIP) with a k2 value of 1.554×10–2 L/mg min from a 40 mg/L CIP concentration. Meanwhile, the employed LED-based photoreactor consumed 0.60 kWh during the entire process. Several experimental parameters influencing CIP removal were analyzed. Although adsorption slightly increases with pH, the overall degradation decreases, indicating oxidation is rate-limiting under applied conditions. Moreover, the coexistence of ions during CIP degradation revealed that divalent cations (Ca²⁺, Mg²⁺) modestly enhanced photocatalytic activity, while Cl⁻ and HCO₃⁻ suppressed it, and SO₄² led to a slight improvement. The 10% Ag2O/BiVO4 showed stable performance in photocatalytic cycles. After five cycles, its activity remained high (%XCIP = 83%). It was also effective in tap water (%XCIP = 82%), demonstrating its potential as an alternative degradation medium. Scavenger assays confirm that superoxide, holes, and hydroxyl radicals induce CIP oxidation, supporting the proposed S-scheme carrier-transfer mechanism in the 10% Ag2O/BiVO4. Toxicity assays revealed no significant growth inhibition and a slight growth enhancement in Chlorella vulgaris exposed to treated medium subsequent to CIP photodegradation, supporting the environmental safety of the process under the tested conditions.
{"title":"Highly efficient blue LED-driven photodegradation of ciprofloxacin using novel and green synthesized p-Ag2O/n-BiVO4 heterostructures","authors":"Elizabeth Hermosillo-Arellano , Fidel Martínez-Gutiérrez , Roberto Leyva-Ramos , Erik César Herrera-Hernández , Ignacio René Galindo-Esquivel , René Darío Peralta-Rodríguez , Abraham Aram López-Cano , Esmeralda Mendoza-Mendoza","doi":"10.1016/j.surfin.2026.108596","DOIUrl":"10.1016/j.surfin.2026.108596","url":null,"abstract":"<div><div>Novel green heterostructures of Ag<sub>2</sub>O/BiVO<sub>4</sub> were prepared by a straightforward aqueous precipitation-hydrothermal route at different ratios of Ag<sub>2</sub>O (3, 6, and 10 wt %). Ag<sub>2</sub>O/BiVO<sub>4</sub> heterostructures have scarcely been tested for ciprofloxacin (CIP) photodegradation under blue LED and sunlight exposure. Among the as-synthesized, the 10% Ag<sub>2</sub>O/BiVO<sub>4</sub> delivered the highest performance within 360 min, degrading 85% of CIP (%X<sub>CIP</sub>) with a <em>k<sub>2</sub></em> value of 1.554×10<sup>–2</sup> L/mg min from a 40 mg/L CIP concentration. Meanwhile, the employed LED-based photoreactor consumed 0.60 kWh during the entire process. Several experimental parameters influencing CIP removal were analyzed. Although adsorption slightly increases with pH, the overall degradation decreases, indicating oxidation is rate-limiting under applied conditions. Moreover, the coexistence of ions during CIP degradation revealed that divalent cations (Ca²⁺, Mg²⁺) modestly enhanced photocatalytic activity, while Cl⁻ and HCO₃⁻ suppressed it, and SO₄² led to a slight improvement. The 10% Ag<sub>2</sub>O/BiVO<sub>4</sub> showed stable performance in photocatalytic cycles. After five cycles, its activity remained high (%X<sub>CIP</sub> = 83%). It was also effective in tap water (%X<sub>CIP</sub> = 82%), demonstrating its potential as an alternative degradation medium. Scavenger assays confirm that superoxide, holes, and hydroxyl radicals induce CIP oxidation, supporting the proposed S-scheme carrier-transfer mechanism in the 10% Ag<sub>2</sub>O/BiVO<sub>4</sub>. Toxicity assays revealed no significant growth inhibition and a slight growth enhancement in <em>Chlorella vulgaris</em> exposed to treated medium subsequent to CIP photodegradation, supporting the environmental safety of the process under the tested conditions.</div></div>","PeriodicalId":22081,"journal":{"name":"Surfaces and Interfaces","volume":"84 ","pages":"Article 108596"},"PeriodicalIF":6.3,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-26DOI: 10.1016/j.surfin.2026.108599
Tarun Kulshrestha , Brian Abbey , Malay K. Das , K. Muralidhar , Ing Kong
Fused deposition modeling (FDM) using metal-infused thermoplastics offers a promising route for developing functional surfaces for phase change heat transfer applications. This approach combines the design flexibility of additive manufacturing with enhanced thermal properties imparted by metallic fillers. In this study, copper-filled heat-treatable PLA (Cu-HTPLA) and standard PLA were employed to systematically investigate the influence of extruder temperature, print speed, and groove orientation on surface morphology, wettability, and condensation behaviour. Samples were fabricated under varied processing conditions and characterized using contact angle goniometry and scanning electron microscopy, while in situ temperature measurements were used to determine thermal conductivity. Anisotropic wetting was observed, arising from ridge–valley microstructures formed during deposition, with Cassie–Baxter-like states appearing perpendicular to the filament layers and Wenzel-like wetting along them. Increasing the extruder temperature reduced hydrophobicity due to viscosity-induced changes in surface roughness, whereas print speed primarily affected surface topography and geometric fidelity. Surface wettability requirements for sustained condensation drop dynamics were achieved at an extruder temperature of 210 °C and a print speed of 15 mm/s. Furthermore, Cu-HTPLA exhibits approximately 90% higher thermal conductivity than PLA. These findings demonstrate that FDM processing parameters can be effectively tuned to engineer functional metal–polymer composite surfaces with tailored wettability and thermal properties, essential for sustained dropwise condensation and drop mobility, thereby enabling a strong potential for applications in solar desalination and atmospheric water harvesting.
{"title":"Dropwise condensation on fused deposition modeling fabricated copper-infused heat-treatable polylactic acid substrates","authors":"Tarun Kulshrestha , Brian Abbey , Malay K. Das , K. Muralidhar , Ing Kong","doi":"10.1016/j.surfin.2026.108599","DOIUrl":"10.1016/j.surfin.2026.108599","url":null,"abstract":"<div><div>Fused deposition modeling (FDM) using metal-infused thermoplastics offers a promising route for developing functional surfaces for phase change heat transfer applications. This approach combines the design flexibility of additive manufacturing with enhanced thermal properties imparted by metallic fillers. In this study, copper-filled heat-treatable PLA (Cu-HTPLA) and standard PLA were employed to systematically investigate the influence of extruder temperature, print speed, and groove orientation on surface morphology, wettability, and condensation behaviour. Samples were fabricated under varied processing conditions and characterized using contact angle goniometry and scanning electron microscopy, while in situ temperature measurements were used to determine thermal conductivity. Anisotropic wetting was observed, arising from ridge–valley microstructures formed during deposition, with Cassie–Baxter-like states appearing perpendicular to the filament layers and Wenzel-like wetting along them. Increasing the extruder temperature reduced hydrophobicity due to viscosity-induced changes in surface roughness, whereas print speed primarily affected surface topography and geometric fidelity. Surface wettability requirements for sustained condensation drop dynamics were achieved at an extruder temperature of 210 °C and a print speed of 15 mm/s. Furthermore, Cu-HTPLA exhibits approximately 90% higher thermal conductivity than PLA. These findings demonstrate that FDM processing parameters can be effectively tuned to engineer functional metal–polymer composite surfaces with tailored wettability and thermal properties, essential for sustained dropwise condensation and drop mobility, thereby enabling a strong potential for applications in solar desalination and atmospheric water harvesting.</div></div>","PeriodicalId":22081,"journal":{"name":"Surfaces and Interfaces","volume":"84 ","pages":"Article 108599"},"PeriodicalIF":6.3,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-26DOI: 10.1016/j.surfin.2026.108607
Wei Guo , Jiaxiang Zhang , Jun Bao
Acting as the crucial sites for chemical reactions, surfaces and interfaces play a decisive role in the overall performance of materials. Probing interfacial chemical reactions still remains an attractive issue, and spectroscopic techniques provide indispensable means for their direct characterization. However, conventional spectroscopic techniques are more or less interfered by the bulk phase, which poses difficulties for conducting in-depth studies of chemical reactions on surfaces and interfaces at the molecular-level. Fortunately, sum frequency generation (SFG) spectroscopy overcomes the limitation by providing intrinsic surface/interface specificity, whose signal arises solely from non-centrosymmetric environments and excludes signal from centrosymmetric bulk phase. As a second order nonlinear spectroscopy with sub-monolayer molecular sensitivity, SFG spectroscopy delivers molecular vibrational spectra of surfaces and interfaces to reveal the chemical identity, bonding, orientation and dynamics under in situ/operando conditions. This review is center on interfacial chemical reactions, underscoring the pivotal and irreplaceable role of SFG spectroscopy in elucidating fundamental molecular-level mechanisms and enabling the rational design of systems in interfacial science. Following a brief overview of the fundamental principles of SFG spectroscopy, we elucidate its central role in the characterization of interfacial chemical reactions, alongside a discussion of its prominent applications in diverse research areas including polymer interfaces, catalysis, and electrochemistry. We conclude by summarizing the insights gained and discussing future opportunities for SFG spectroscopy in advancing interfacial chemistry.
{"title":"Sum frequency generation spectroscopy: Probing chemical reactions at surfaces and interfaces","authors":"Wei Guo , Jiaxiang Zhang , Jun Bao","doi":"10.1016/j.surfin.2026.108607","DOIUrl":"10.1016/j.surfin.2026.108607","url":null,"abstract":"<div><div>Acting as the crucial sites for chemical reactions, surfaces and interfaces play a decisive role in the overall performance of materials. Probing interfacial chemical reactions still remains an attractive issue, and spectroscopic techniques provide indispensable means for their direct characterization. However, conventional spectroscopic techniques are more or less interfered by the bulk phase, which poses difficulties for conducting in-depth studies of chemical reactions on surfaces and interfaces at the molecular-level. Fortunately, sum frequency generation (SFG) spectroscopy overcomes the limitation by providing intrinsic surface/interface specificity, whose signal arises solely from non-centrosymmetric environments and excludes signal from centrosymmetric bulk phase. As a second order nonlinear spectroscopy with sub-monolayer molecular sensitivity, SFG spectroscopy delivers molecular vibrational spectra of surfaces and interfaces to reveal the chemical identity, bonding, orientation and dynamics under <em>in situ</em>/<em>operando</em> conditions. This review is center on interfacial chemical reactions, underscoring the pivotal and irreplaceable role of SFG spectroscopy in elucidating fundamental molecular-level mechanisms and enabling the rational design of systems in interfacial science. Following a brief overview of the fundamental principles of SFG spectroscopy, we elucidate its central role in the characterization of interfacial chemical reactions, alongside a discussion of its prominent applications in diverse research areas including polymer interfaces, catalysis, and electrochemistry. We conclude by summarizing the insights gained and discussing future opportunities for SFG spectroscopy in advancing interfacial chemistry.</div></div>","PeriodicalId":22081,"journal":{"name":"Surfaces and Interfaces","volume":"84 ","pages":"Article 108607"},"PeriodicalIF":6.3,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-25DOI: 10.1016/j.surfin.2026.108598
Sajjad Hussain , Abdulaziz A. Al-Saadi
The catalytic reduction of CO2 into value-added chemicals using renewable energy is a promising strategy for effective CO2 management, but it often competes with the hydrogen evolution reaction (HER). Herein, we present a systematic first-principles investigation of Zr12O12 and M@Zr12O12 (M = Fe, Co, Ni, Cu, Zn) nanocages to elucidate their potential as photocatalysts for the CO2 reduction reaction (CO2RR). We reveal that late 3d transition metals with partially filled d orbitals (Fe, Co, and Ni) are stably anchored on the Zr12O12 nanocages, whereas Cu and Zn atoms are not stabilized due to their fully filled d orbitals. The pristine zinc oxide nanocage exhibits a band gap of 2.07 eV and can convert CO2 to CO under a low potential of 0.71 eV. Loading with Fe, Co, or Ni further narrows the band gap and enhances CO2 activation. However, CO desorption from Fe@Zr12O12, Co@Zr12O12, and Ni@Zr12O12 is hindered by large energy barriers. Interestingly, Ni@Zr12O12 facilitates spontaneous CO2 reduction to OCCO, a key intermediate for C₂ products, though its strong H adsorption may block active sites. In contrast, the non-doped cage, and the corresponding Fe@Zr12O12, and Co@Zr12O12 can form OCCO under low external energies, with Fe- and Co-loaded nanocages showing higher CO2 selectivity over HER. These findings provide atomistic level insights for engineering single-atom Zr-oxide photocatalysts for selective CO2 reduction to C2 products.
{"title":"First-principles insights into CO2 reduction and competing HER on transition metal-loaded Zr12O12 nanocages","authors":"Sajjad Hussain , Abdulaziz A. Al-Saadi","doi":"10.1016/j.surfin.2026.108598","DOIUrl":"10.1016/j.surfin.2026.108598","url":null,"abstract":"<div><div>The catalytic reduction of CO<sub>2</sub> into value-added chemicals using renewable energy is a promising strategy for effective CO<sub>2</sub> management, but it often competes with the hydrogen evolution reaction (HER). Herein, we present a systematic first-principles investigation of Zr<sub>12</sub>O<sub>12</sub> and M@Zr<sub>12</sub>O<sub>12</sub> (<em>M</em> = Fe, Co, Ni, Cu, Zn) nanocages to elucidate their potential as photocatalysts for the CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR). We reveal that late 3<em>d</em> transition metals with partially filled <em>d</em> orbitals (Fe, Co, and Ni) are stably anchored on the Zr<sub>12</sub>O<sub>12</sub> nanocages, whereas Cu and Zn atoms are not stabilized due to their fully filled <em>d</em> orbitals. The pristine zinc oxide nanocage exhibits a band gap of 2.07 eV and can convert CO<sub>2</sub> to CO under a low potential of 0.71 eV. Loading with Fe, Co, or Ni further narrows the band gap and enhances CO<sub>2</sub> activation. However, CO desorption from Fe@Zr<sub>12</sub>O<sub>12</sub>, Co@Zr<sub>12</sub>O<sub>12</sub>, and Ni@Zr<sub>12</sub>O<sub>12</sub> is hindered by large energy barriers. Interestingly, Ni@Zr<sub>12</sub>O<sub>12</sub> facilitates spontaneous CO<sub>2</sub> reduction to OCCO, a key intermediate for C₂ products, though its strong H adsorption may block active sites. In contrast, the non-doped cage, and the corresponding Fe@Zr<sub>12</sub>O<sub>12</sub>, and Co@Zr<sub>12</sub>O<sub>12</sub> can form OCCO under low external energies, with Fe- and Co-loaded nanocages showing higher CO<sub>2</sub> selectivity over HER. These findings provide atomistic level insights for engineering single-atom Zr-oxide photocatalysts for selective CO<sub>2</sub> reduction to C<sub>2</sub> products.</div></div>","PeriodicalId":22081,"journal":{"name":"Surfaces and Interfaces","volume":"84 ","pages":"Article 108598"},"PeriodicalIF":6.3,"publicationDate":"2026-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146049121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-25DOI: 10.1016/j.surfin.2026.108595
Chongyang Wang , Fuyi Chen
Surface stress plays a basic role in understanding surface phenomena on noble metals. However, systematic investigations into its fundamental origins and distribution discrepancy between equilibrium and non-equilibrium surfaces remain lacking. Herein, ReaxFF molecular dynamics simulations were employed to directly characterize the atomic-scale stress on Pd and Ag surface structures. Unrelaxed pristine surfaces exhibit anisotropic stress distributions along the x-, y-, and z-axes directions. On relaxed surfaces, pronounced tensile stress is concentrated within the top-layer region, existing solely as components within the horizontal plane along the x- and y-axes, while the component along the z-axis vanishes. Crystallographic orientation dictates distinct oxidation mechanisms: (100) and (111) surfaces involve the formation of 2D oxide overlayers and islands, whereas direct bulk diffusion of oxygen atoms dominates the (110) surface. Analysis of the overall trend reveals a clear crystallographic orientation dependence in the oxidation rate: (110) > (100) > (111), and (100) and (110) surfaces are significantly governed by temperature, contrasting with pressure dependence on (111). Nonetheless, Ag and Pd display kinetic discrepancy during different oxidation stages: Ag dominates initial oxidation, with subsequent reversal to Pd prevailing until oxidation completion. The oxidized surfaces show significant residual tensile stresses that spread throughout the oxide layer, and their propagation distance correlates positively with the vertical diffusion depth of oxygen atoms during oxidation.
{"title":"Surface stress evolution and kinetics of Ag and Pd surfaces during oxidation","authors":"Chongyang Wang , Fuyi Chen","doi":"10.1016/j.surfin.2026.108595","DOIUrl":"10.1016/j.surfin.2026.108595","url":null,"abstract":"<div><div>Surface stress plays a basic role in understanding surface phenomena on noble metals. However, systematic investigations into its fundamental origins and distribution discrepancy between equilibrium and non-equilibrium surfaces remain lacking. Herein, ReaxFF molecular dynamics simulations were employed to directly characterize the atomic-scale stress on Pd and Ag surface structures. Unrelaxed pristine surfaces exhibit anisotropic stress distributions along the x-, y-, and z-axes directions. On relaxed surfaces, pronounced tensile stress is concentrated within the top-layer region, existing solely as components within the horizontal plane along the x- and y-axes, while the component along the z-axis vanishes. Crystallographic orientation dictates distinct oxidation mechanisms: (100) and (111) surfaces involve the formation of 2D oxide overlayers and islands, whereas direct bulk diffusion of oxygen atoms dominates the (110) surface. Analysis of the overall trend reveals a clear crystallographic orientation dependence in the oxidation rate: (110) > (100) > (111), and (100) and (110) surfaces are significantly governed by temperature, contrasting with pressure dependence on (111). Nonetheless, Ag and Pd display kinetic discrepancy during different oxidation stages: Ag dominates initial oxidation, with subsequent reversal to Pd prevailing until oxidation completion. The oxidized surfaces show significant residual tensile stresses that spread throughout the oxide layer, and their propagation distance correlates positively with the vertical diffusion depth of oxygen atoms during oxidation.</div></div>","PeriodicalId":22081,"journal":{"name":"Surfaces and Interfaces","volume":"84 ","pages":"Article 108595"},"PeriodicalIF":6.3,"publicationDate":"2026-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-24DOI: 10.1016/j.surfin.2026.108588
Yue Su, Jie Li, Shengli Wu, Wenbo Hu
There is a significant demand for high secondary electron emission (SEE) coefficients and long operational lifetimes in vacuum electronic devices. Therefore, the fabrication of thin films with excellent SEE performance has become increasingly critical. In this study, we demonstrate a simple yet effective approach to enhance the SEE coefficient and simultaneously reduce the decay rate of Al and Au co-doped MgO films by introducing a buffer layer and tuning its thickness. By investigating the crystallization behavior of films with varying buffer layer thicknesses, we reveal that the buffer layer significantly influences the surface morphology, chemical states, and band structure of the films, all of which play important roles in determining the final SEE performance. Notably, the Al and Au co-doped MgO film with a 40 nm-thick Al buffer layer exhibited the best SEE performance, improving the SEE coefficient from 5.03 to 5.32 while alleviating the decay rate from 13.6% to 9.8%. Compared to traditional approaches involving complex structural design, the strategy of incorporating a buffer layer offers a simple, reproducible, and scalable method for the fabrication of high-performance SEE films. The suitability of the optimized films for use in multipliers was demonstrated by the remarkable performance enhancement achieved upon their integration into the devices.
{"title":"Influence of Al Buffer Layer Thickness on SEE Properties of Al and Au Co-doped MgO Film","authors":"Yue Su, Jie Li, Shengli Wu, Wenbo Hu","doi":"10.1016/j.surfin.2026.108588","DOIUrl":"10.1016/j.surfin.2026.108588","url":null,"abstract":"<div><div>There is a significant demand for high secondary electron emission (SEE) coefficients and long operational lifetimes in vacuum electronic devices. Therefore, the fabrication of thin films with excellent SEE performance has become increasingly critical. In this study, we demonstrate a simple yet effective approach to enhance the SEE coefficient and simultaneously reduce the decay rate of Al and Au co-doped MgO films by introducing a buffer layer and tuning its thickness. By investigating the crystallization behavior of films with varying buffer layer thicknesses, we reveal that the buffer layer significantly influences the surface morphology, chemical states, and band structure of the films, all of which play important roles in determining the final SEE performance. Notably, the Al and Au co-doped MgO film with a 40 nm-thick Al buffer layer exhibited the best SEE performance, improving the SEE coefficient from 5.03 to 5.32 while alleviating the decay rate from 13.6% to 9.8%. Compared to traditional approaches involving complex structural design, the strategy of incorporating a buffer layer offers a simple, reproducible, and scalable method for the fabrication of high-performance SEE films. The suitability of the optimized films for use in multipliers was demonstrated by the remarkable performance enhancement achieved upon their integration into the devices.</div></div>","PeriodicalId":22081,"journal":{"name":"Surfaces and Interfaces","volume":"84 ","pages":"Article 108588"},"PeriodicalIF":6.3,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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