CuO Species Research Articles

Promoting effect of post-synthesis treatment strategy on NH3-SCR performance and hydrothermal stability of Cu-SAPO-18

The influence of post-synthesis treatment with MnSO4, (NH4)2SO4 and (NH4)2S2O8 blended solution on NH3-SCR activity and hydrothermal stability of Cu-SAPO-18 (Cu-18) was investigated. Via adjusting the mixed solution concentration, the optimal Mn/Cu-18-Ⅲ with higher deNOx activity and hydrothermal stability was acquired. Based on the optimal Mn/Cu-18-Ⅲ, diverse metal cations such as La3+, Ce3+, Sm3+ or Zr4+ were simultaneously doped into Cu-18 during Mn2+ and NH4+ blended solution treatment to further promote its catalytic performance before and after hydrothermal treatment. The doping with Sm could improve the NH3 activity and hydrothermal stability of Mn/Cu-18-Ⅲ to the greatest extent. The elevation of acid sites content and the disappearance of CuO species in Mn/Cu-18-Ⅲ caused the enhancement of its NH3-SCR activity. More Cu2+ and acid sites in SmMn/Cu-18-Ⅲ were responsible for its higher NH3-SCR activity than Mn/Cu-18-Ⅲ. The decline of vulnerable Brønsted acid sites by substituting Mn2+ or Sm3+ for H+ could restrain the hydrolysis of Cu-18 and enhance the hydrothermal stability of Cu-18 during hydrothermal treatment. The mechanism analysis demonstrates that the fresh and aged Cu-18, Mn/Cu-18-Ⅲ and SmMn/Cu-18-Ⅲ follow both Eley–Rideal (E–R) and Langmuir–Hinshelwood (L–H) mechanism in NH3-SCR reaction, with the L–H mechanism being more dominated.

CuZnAl-Oxide Nanopyramidal Mesoporous Materials for the Electrocatalytic CO2 Reduction to Syngas: Tuning of H2/CO Ratio.

Inspired by the knowledge of the thermocatalytic CO2 reduction process, novel nanocrystalline CuZnAl-oxide based catalysts with pyramidal mesoporous structures are here proposed for the CO2 electrochemical reduction under ambient conditions. The XPS analyses revealed that the co-presence of ZnO and Al2O3 into the Cu-based catalyst stabilize the CuO crystalline structure and introduce basic sites on the ternary as-synthesized catalyst. In contrast, the as-prepared CuZn- and Cu-based materials contain a higher amount of superficial Cu0 and Cu1+ species. The CuZnAl-catalyst exhibited enhanced catalytic performance for the CO and H2 production, reaching a Faradaic efficiency (FE) towards syngas of almost 95% at −0.89 V vs. RHE and a remarkable current density of up to 90 mA cm−2 for the CO2 reduction at −2.4 V vs. RHE. The physico-chemical characterizations confirmed that the pyramidal mesoporous structure of this material, which is constituted by a high pore volume and small CuO crystals, plays a fundamental role in its low diffusional mass-transfer resistance. The CO-productivity on the CuZnAl-catalyst increased at more negative applied potentials, leading to the production of syngas with a tunable H2/CO ratio (from 2 to 7), depending on the applied potential. These results pave the way to substitute state-of-the-art noble metals (e.g., Ag, Au) with this abundant and cost-effective catalyst to produce syngas. Moreover, the post-reaction analyses demonstrated the stabilization of Cu2O species, avoiding its complete reduction to Cu0 under the CO2 electroreduction conditions.

Mesoporous CuO/TiO2 catalysts prepared by the ammonia driven deposition precipitation method for CO preferential oxidation: Effect of metal loading

Supported CuO catalysts onto a highly crystalline mesoporous TiO2 material are produced via an ammonium driven deposition precipitation method and tested for preferential oxidation of CO in H2-rich gases. The effect of Cu loading on the oxidation activity is investigated by producing samples with final Cu content varying between 2.5 and 10 wt%. According to the analysis results, the chemical nature of the CuO species differs in each sample depending on the Cu loading. All materials tested are highly selective towards CO oxidation up to 160 °C. The 5 wt% Cu loaded material demonstrates the optimum CO-PROX performance, which is ascribed to the formation of finely dispersed and easily reducible copper oxide nanoparticles. Stability and durability of the latter sample are assessed by performing multiple testing cycles corresponding to >100hrs on stream as well as by the separate and combined addition of CO2 and H2O in the feeding stream.

Novel insights into diethylamine catalytic combustion over CuO catalysts supported by SSZ-13: Undesirable product NOx as a crucial intermediate for N2 generation

Catalytic combustion of nitrogen-containing volatile organic compounds (NVOCs) could effectively control N2 generation rather than NOx, but its mechanism is still not well answered. Herein, a series of CuO supported by SSZ-13 catalysts (denoted as Cu/S) were prepared for the catalytic combustion of diethylamine (DEA), a typical NVOCs. The effects of CuO loading and calcined temperature of catalysts on the catalytic performance were investigated. Among the Cu/S catalysts, the 10CuO/S-450 catalyst exhibits the highest oxidation activity (lowest T99 of 240 °C), and widest temperature window (△T = 120 °C) for high N2 selectivity (>99%). This result is ascribed to its highest ratio of easily reduced CuO active species. Importantly, there are two important steps for DEA combustion (I: catalytic oxidation to NOx; II: selective catalytic reduction of NOx with DEA to N2). Selective catalytic reduction of NOx with DEA is the very crucial pathway for N2 generation. The easily reduced CuO species play crucial roles on both catalytic oxidation and selective catalytic reduction. In addition, water vapor (5 vol.%) slightly improved oxidation activity of DEA, and increased N2 selectivity at high temperature (>350 °C), but the catalytic oxidation activity of intermediate CO was decreased caused by the competitive adsorption of water vapor.

On the CuO-Mn2O3 oxide-pair in CuMnOx multi-oxide complexes: Structural and catalytic studies

The current work provide a new understanding on the active site of CuMnOx catalysts and thus offer a new perspective in the development of highly effective and low cost CuMnOx catalysts for heterogeneous catalytic oxidation reactions. A series of dual-component copper-manganese multi-oxide catalysts (CuMnOx) have been successfully synthesized using a surfactant assisted hydrolysis-hydrothermal method and studied by XRD, N2 adsorption–desorption test, ICP-AES, SEM, Aberration-corrected HADDF-STEM, HRTEM, FT-IR, Raman, XPS, H2-TPR. These CuMnOx catalysts were found to be composed with uniform CuO-Mn2O3 oxide pair structure, in which highly isolated/dispersed CuO species are anchored in the framework of Mn2O3. It was found that the speciation in these CuMnOx catalysts presents a shift from highly isolated or even single Cu2+ oxide species (Cu2+Ox) to CuO nanoclusters and CuO microcrystalline with increasing Cu content. In CO oxidation reaction, which was employed to probe the structure of the CuO-Mn2O3 oxide pairs in these CuMnOx catalysts, the Cu-O-Mn sites in those CuMnOx catalysts with highly isolated or highly dispersed CuO species were found to be highly active. For CuO-Mn2O3 oxide pair catalysts, the highly isolated/dispersed CuO species in Mn2O3 framework is essential to achieve high activity.

Combustion-Synthesized Porous CuO-CeO2-SiO2 Composites as Solid Catalysts for the Alkenylation of C(sp3)-H Bonds Adjacent to a Heteroatom via Cross-Dehydrogenative Coupling

A series of mixed oxides of CuO, CeO2, and SiO2 were prepared by gel combustion and employed for the first time as efficient solid catalysts in a solvent-less liquid-phase cross-dehydrogenative coupling. The facile one-pot catalyst synthesis resulted in highly porous materials presenting large specific surface areas and strong metal–support interactions. The interaction with highly dispersed CeO2 enhanced the redox properties of the CuO species. The CuO-CeO2-SiO2 composites exhibited excellent catalytic performance for the selective coupling between 1,1-diphenylethylene and tetrahydrofuran with a yield up to 85% of 2-(2,2-diphenylvinyl)-tetrahydrofuran in the presence of di-tert-butyl peroxide (DTPB) and KI. Albeit both CuO and CeO2 species are proved to be responsible for the catalytic conversion, a great synergistic improvement in the catalytic activity was obtained by extended contact between the oxide phases by high porosity in comparison with the reactions using individual Cu or Ce catalysts. The activity of the composite catalyst was shown to be highly stable after five successive reaction cycles. Furthermore, the study scope was extended to the synthesis of different derivatives via composite-catalyzed coupling of C(sp2)-H with C(sp3-H) adjacent to a heteroatom. The good yields recorded proved the general validity of this composite for the cross-dehydrogenative coupling reaction rarely performed on solid catalysts.

Caffeine photocatalytic degradation using composites of NiO/TiO2–F and CuO/TiO2–F under UV irradiation

The interest in the removal of emerging contaminants has increased in the last decade. Photocatalytic degradation using p-n heterojunctions could effectively provide the degradation of these type of substances that are persistent in the environment. In this work, the synthesis, characterization, and photocatalytic evaluation of TiO2–F as well as CuO/TiO2–F and NiO/TiO2–F composite materials were studied in the photo-assisted degradation of caffeine using UV radiation. The fluorination of titanium dioxide induced changes in some physicochemical properties of the materials, which contributed to a decrease in surface area and bandgap energy as well as an increase in crystallite size as compared to pristine TiO2. ≡Ti–F species were evidenced to be formed, which could favor charge separation processes. A highest segregation of CuO species in comparison with NiO on the surface of TiO2–F could be formed, which could increase defect sites and decrease the band gap. The formation of a heterojunction between the semiconductors was evidenced, responsible for the observed improvements in photocatalytic properties of the composite materials. The photocatalytic tests evidenced an important degradation of caffeine; however, mineralization was incomplete. The stability of the composite materials and their potential use in the photocatalytic treatment of caffeine was evaluated by reuse tests.

Aluminum Doped Titania as a Support of Copper Catalysts for SCR of Nitrogen Oxides.

Aluminum doped titania samples were synthesized as supports of copper oxide catalysts for NO reduction with ammonia. Samples were prepared by the sol-gel method with various ratios of aluminum to titanium. Their thermal stability was examined by TG/DSC methods which revealed that precursors were decomposed at 450 °C. The XRD measurements showed that aluminum caused the diminishing of titania crystallites and was built into the anatase structure or formed an amorphous phase. The admixture of aluminum in titania resulted in a significant increase in specific surface area of mesoporous supports as determined by low temperature sorption of nitrogen. Results of the catalytic tests over copper/aluminum-titania samples obtained by impregnation pointed out that the addition of aluminum broadened the temperature window of high catalytic activity. The increase in Al concentration shifted the temperature of maximum activity to higher values, and at the same time lowered nitrous oxide formation as well. Better catalytic efficiency could result from high copper dispersion on the catalysts surface, as well as the synergistic interaction between Ti and Cu causing reduction in CuO species as confirmed by XPS measurements. It was shown that copper was present as Cu+ species mainly, forming Cu-O-Ti bonds on the catalysts surface.

Dual immobilization of Pd[sbnd]Cu nanoparticles on halloysite nanotubes by CTAB and PVP for automobile exhaust elimination

Low thermal stability and metal sintering are considered the reasons for the deactivation of three-way catalysts, especially on transition metals. Herein, using a versatile clay halloysite nanotubes (Hal) as a support and two surfactants, cetyltrimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP), modified Hal with hydrophobic external surfaces and Pd-PVP colloids with various particle sizes were synthesized by adjusting the ratios of surfactants. As a result, modified Hal could make CuO nanoparticles coordinate with unsaturated Al in the internal lumen of Hal, which is favored to increase the CuO nanoparticle dispersion and inhibit their migration. In particular, Cu@HC-2 (Hal/CTAB weight ratio = 2) exhibited a higher n(Cu)/n(Al) ratio, surface active oxygen species and CuO species, which endowed better catalytic performance. The T50 of CO conversion decreased from 250 °C (unmodified Cu/Hal catalyst) to 180 °C. However, the NOx reduction is less effective due to the limited reducibility of transition metal. The reduced Pd-PVP nanoparticles with the molar ratio of PVP/Pd = 4 were immobilized on the Cu-based catalyst, which contributes to the smaller Pd0 nanoparticles and the maximum NOx conversion. Unexpectedly, excessive PVP-Pd may block the gas reaction with CuO species and weaken the CO and C3H8 oxidation.

Insight into the Morphology-Dependent Catalytic Performance of CuO/CeO2 Produced by Tannic Acid for Efficient Hydrogenation of 4-Nitrophenol.

The construction of a heterogeneous nanocatalyst with outstanding catalytic performance via an environmentally benign and cost-effective synthetic category has long been one of the challenges in nanotechnology. Herein, we synthesized highly efficient and low-cost mesoporous morphology-dependent CuO/CeO2 -Rods and CuO/CeO2 -Cubes catalysts by employing a green and multifunctional polyphenolic compound (tannic acid) as the stabilizer and chelating agent for 4-nitrophenol (4-NP) reduction reaction. The CuO/CeO2 -Rods exhibited excellent performance, of which the activity was 3.2 times higher than that of CuO/CeO2 -Cubes. This can be connected with the higher density of oxygen vacancy on CeO2 -Rods (110) than CeO2 -Cubes (100), the oxygen vacancy favors anchoring CuO species on the CeO2 support, which promotes the strong interaction between finely dispersed CuO and CeO2 -Rods at the interfacial positions and facilitates the electron transfer from BH4 - to 4-NP. The synergistic catalytic mechanism illustrated that 4-NP molecules preferentially adsorbed on the CeO2 , while H2 from BH4 - dissociated over CuO to form highly active H* species, contributing to achieving efficient hydrogenation of 4-NP. This study is expected to shed light on designing and synthesizing cost-effective and high-performance nanocatalysts through a greener synthetic method for the areas of catalysis, nanomaterial science and engineering, and chemical synthesis.

Manipulating Cu Nanoparticle Surface Oxidation States Tunes Catalytic Selectivity toward CH4 or C2+ Products in CO2 Electroreduction

AbstractHerein, a facile seed‐assisted strategy for preparing Cu nanoparticles (NPs) with polyvinyl pyrrolidone (PVP) capping is presented. Compared to the Cu NPs with deficient PVP protection, the Cu NPs capped with a sufficient amount of PVP remain almost completely as Cu0 species. In contrast, the Cu NPs that are considered PVP deficient form an oxide structure in which the inner layer is face‐centered cubic Cu and the outer layer is, at least in part, made up of Cu2O species. Furthermore, to eliminate CO2 molecule diffusion and simultaneously obtain significant current density (200 mA cm−2) for industrial applications, a flow cell configuration is used for carbon dioxide electro reduction reaction (CO2RR) testing in 0.5 m potassium hydroxide solution. The Cu NPs with zero valence deliver Faradaic efficiencies (FEs) for the CO2 reduction to CH4 of over 70%, with a current density exceeding 200 mA cm−2, outstripping the performances of the majority of the reported CO2 electrocatalysts. Interestingly, the distribution of products catalyzed by the Cu NPs with +1 valence includes multicarbon products (C2+) such as C2H4, C2H5OH, CH3COOH, and C3H7OH with combined FEs of >80%, with current densities of up to 300 mA cm−2. The above results unambiguously establish that surface oxidation of Cu species plays a crucial role in the CO2RR.

Enhanced Activity for CO Preferential Oxidation over CuO Catalysts Supported on Nanosized CeO2 with High Surface Area and Defects

Nanosizedceria (n-CeO2) was synthesized by a facile method in 2-methylimidazolesolution. The characterization results of XRD, N2 adsorption-desorption, Raman and TEM indicate that n-CeO2 shows a regular size of 10 ± 1 nm, a high surface area of 130 m2·g−1 and oxygen vacancies on the surface. A series of CuO/n-CeO2 catalysts (CuCeOX) with different copper loading were prepared for the preferential oxidation of CO in H2-rich gases (CO-PROX). All CuCeOX catalysts exhibit a high catalytic activity due to the excellent structural properties of n-CeO2, over which the 100% conversion of CO is obtained at 120 °C. The catalytic activity of CuCeOX catalysts increases in the order of CuCeO12 < CuCeO3 < CuCeO6 < CuCeO9. It is in good agreement with the order of the amount of active Cu+ species, Ce3+ species and oxygen vacancies on these catalysts, suggesting that the strength of interaction between highly dispersed CuO species and n-CeO2 is the decisive factor for the activity. The stronger interaction results in the formation of more readily reducible copper species on CuCeO9, which shows the highest activity with high stability and the broadest temperature “window” for complete CO conversion (120–180 °C).

TiO2 Facet-dependent reconstruction and photocatalysis of CuOx/TiO2 photocatalysts in CO2 photoreduction

A series of CuOx/TiO2 photocatalysts with different TiO2 nanocrystals as the supports were prepared to explore the effect of CuOx-TiO2 interaction on the reconstruction and photocatalysis in CO2 photoreduction with water as the reducing agent. The CuOx-TiO2 interaction was observed to be strongest in CuOx/TiO2-{001} photocatalysts. Under Xe light irradiation, supported CuO species on TiO2-{001} is photo-reduced to stable supported Cu2O species beneficial for photocatalytic CO2 reduction to CH4, while supported CuOx species on TiO2-{100} and TiO2-{101} is photo-reduced to supported Cu0 species unfavorable for photocatalytic CO2 reduction to CH4. The photo-induced reduction of supported CuOx to Cu0 becomes more severe under Hg light irradiation. In situ diffuse reflectance infrared spectroscopy (DRIFTS) results demonstrate that photocatalytic CO2 reduction to CH4 occurs via the bicarbonate and carboxyl intermediates over all CuOx/TiO2 photocatalysts and via the additional CO2– and formate intermediates over CuOx/TiO2-{100} and CuOx/TiO2-{101} photocatalysts. These results deepen the fundamental understanding of Cu-based photocatalysts for photocatalytic CO2 reduction and exemplify the facet effect of TiO2 nanocrystals in TiO2-related photocatalysis.

Titania-decorated copper oxide nanophotocatalyst powder: A stable and promoted photocatalytic active system

In this work, the synthesis of the CuO-Cu2O nanocomposites decorated with TiO2 nanoparticles was performed by chemical-thermal oxidation and subsequently by the sol–gel method. The X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FESEM) showed using different furnace atmospheres lead to the formation of nanocomposites with variable components content with a mixture of special morphology. The Energy Dispersive X-Ray Analysis (EDX) confirmed the existence of Ti, Cu, and O elements in the composite material. The X-ray photoelectron spectroscopy (XPS) data suggest the presence of CuO and Cu2O species in addition to the TiO2 phase in the as-prepared composite samples. Transmission electron microscopy (TEM) and UV–vis spectroscopy indicated the successful fabrication of multiple heterostructures of TiO2 and copper oxides components. The assessment of gas-phase photocatalytic performance in the 2-propanol photodegradation under both UV and visible light irradiation was done through the measurement of the reaction rate and quantum efficiency. The composite photocatalysts demonstrated about 2.5 times more active photocatalytic behavior in gas phase photo-oxidation compared with the pure CuO-Cu2O and titania because of the simultaneous presence of different copper oxide types in the structure and TiO2 nanoparticles as a surface decorated part. A cascade-type mechanism was also proposed for the photocatalytic behavior of the system. Furthermore, the stability of the specimens was proved during the photocatalytic reaction.

Stable, Efficient, Copper Coordination Polymer-Derived Heterostructured Catalyst for Oxygen Evolution under pH-Universal Conditions.

The constructure of a heterostructured interface is an effective way to design highly durable and efficient water oxidation electrocatalysts. Herein, Cu/CuCN with heterointerfaces is the first synthesized case through a simple epitaxial-like growth method, displaying superior activity and stability under pH-universal media. Associated with high electron transport and transfer of the epitaxial interfacial area, the Cu/CuCN pre-catalyst is applied to deliver the oxygen evolution reaction (OER) with lower overpotentials of 250 mV (forward scan) and 380 mV (backward scan) at 10 mA cm–2 and demonstrates better intrinsic activity (jECSA of 1.0 mA cm–2 at 420 mV) and impressive stability (136 h) in 1.0 M KOH, which exceeds most previous catalysts. Even using a nominal voltage of 1.5 V of a AA battery can drive the overall water-splitting setup. Experiments combined with theoretical simulations further uncover the existence of CuO species at the heterointerface during basic OER, which is evidence of better OER performance with abundant active sites that accelerate the conversion kinetics.

Catalytic Oxygenation of Hydrocarbons by Mono-μ-oxo Dicopper(II) Species Resulting from O-O Cleavage of Tetranuclear CuI /CuII Peroxo Complexes.

One of the challenges of catalysis is the transformation of inert C−H bonds to useful products. Copper‐containing monooxygenases play an important role in this regard. Here we show that low‐temperature oxygenation of dinuclear copper(I) complexes leads to unusual tetranuclear, mixed‐valent μ4‐peroxo [CuI/CuII]2 complexes. These Cu4O2 intermediates promote irreversible and thermally activated O−O bond homolysis, generating Cu2O complexes that catalyze strongly exergonic H‐atom abstraction from hydrocarbons, coupled to O‐transfer. The Cu2O species can also be produced with N2O, demonstrating their capability for small‐molecule activation. The binding and cleavage of O2 leading to the primary Cu4O2 intermediate and the Cu2O complexes, respectively, is elucidated with a range of solution spectroscopic methods and mass spectrometry. The unique reactivities of these species establish an unprecedented, 100 % atom‐economic scenario for the catalytic, copper‐mediated monooxygenation of organic substrates, employing both O‐atoms of O2.

Influence of Copper Locations on Catalytic Properties and Activities of Cu/SAPO-34 in C3H6-SCR

Herein, Cu-modified SAPO-34 catalysts with various copper loadings are synthesized via a pH-controlled ion-exchange method. Cu exists predominantly as isolated cations at lower loadings, located at octahedrally coordinated sites in the ellipsoidal cavity of SAPO-34 zeolites, while CuO is gradually generated on the external surface at higher loadings. Our results reveal that the isolated Cu cations are the active sites for C₃H₆-SCR. The presence of CuO species enhances the C₃H₆ activation ability of the catalysts, which thus, improves the C₃H₆-SCR performance at medium and low temperatures (below 400 °C). At high temperatures, however, the formation of CuO accelerates the nonselective oxidation of C₃H₆ and causes activity decline. These findings suggest that the active temperature window for hydrocarbons-selective catalytic reduction (HC-SCR) reactions over Cu/SAPO-34 catalysts can be tailored by tuning the proportion of various copper species to fit the need in real applications, which provide new insights into understanding and designing highly efficient Cu-based zeolite catalysts.

CuW/CeZr Catalysts: A Dual-Function Catalyst for Selective Catalytic Reduction of NO and CO Oxidation Under Oxygen-Rich Conditions

In this study, a series of CuW/CeZr (denoted as xCu–yW–CZ hereafter) catalysts with both NO reduction and CO oxidation activity was synthesized by the co-impregnation method, aiming for simultaneous removal of NO and CO under oxygen-rich conditions. Characterizations including N2 adsorption and desorption, XRD, SEM, H2–TPR, and NH3–TPD were used to interpret the influence of WO3/CuO loading amount on catalytic activity. The results suggested that the addition of WO3 species increased the surface acidity of the catalyst while weakening its redox property. On the contrary, the addition of CuO species greatly enhanced the redox property of the catalyst while hardly changing its surface acidity. Notably, too high content CuO was prone to aggregate, which was unfavorable to catalytic activity. Consequently, 5Cu–10W–CZ with 5 wt% CuO and 10 wt% WO3 presented the most optimal catalytic activity because of high components dispersion, appropriate redox property, and surface acidity. A novel dual-function catalyst (CuW/CeO2–ZrO2) that can simultaneously catalyze NH3–SCR reaction and CO oxidation reaction, was synthesized by the co-impregnation method, aiming for simultaneous removal of NO and CO under oxygen-rich conditions.

Electrodeposition of Cu2O nanostructures with improved semiconductor properties

In the present research, nanocomposites based on copper (I) oxide poly(1-vinyl-2—pyrolidone-co-itaconic acid) nanostructures (Cu2O/p(NVP-co-AI)) were synthesized by the electrodeposition method using the copolymer p(NVP-co-AI) as a stabilizing agent in the reduction of Cu+2 to Cu+. The chemical and physical properties of the nanostructures were characterized by techniques such as scanning electron microscopy, infrared (IR) spectroscopy, Raman and ultraviolet-visible spectrophotometry. The obtained nanostructures are mainly a mixture of agglomerated nanospheres with a diameter of approximately 78 to 91 nm, with an alternation of nanolaminar structures, composed of copper (I) oxide species. In the case of the Cu2O/p(NVP-co-AI) nanocomposite, it was observed a decrease in the carbon-oxygen vibration links of the carbonyl groups in IR intensity for the polymer when it was dissolved in the electrolytic solution, which indicates that interactions are produced by the carbonyl groups with the Cu2O species. In addition, bandgap values of 1.80 and 1.63 eV were estimated by the Kubelka–Munk method for Cu2O and Cu2O/p(NVP-co-AI) samples, respectively.

In-Depth Investigation of Copper Surface Chemistry Modification by Ultrashort Pulsed Direct Laser Interference Patterning.

Surface patterning in the micro- and nanometer-range by means of pulsed laser interference has repeatedly proven to be a versatile tool for surface functionalization. With these techniques, however, the surface is often changed not only in terms of morphology but also in terms of surface chemistry. In this study, we present an in-depth investigation of the chemical surface modification occurring during surface patterning of copper by ultrashort pulsed direct laser interference patterning (USP-DLIP). A multimethod approach of parallel analysis using visualizing, topography-sensitive, and spectroscopic techniques allowed a detailed quantification of surface morphology as well as composition and distribution of surface chemistry related to both processing and atmospheric aging. The investigations revealed a heterogeneous surface composition separated in peak and valley regions predominantly consisting of Cu2O, as well as superficial agglomerations of CuO and carbon species. The evaluation was supported by a modeling approach for the quantification of XPS results in relation to heterogeneous surface composition, which was observed by means of a combination of different spectroscopic techniques. The overall results provide a detailed understanding of the chemical and topographical surface modification during USP-DLIP, which allows a more targeted use of this technology for surface functionalization.