Number Of Surface Active Sites Research Articles

Experimental study of the catalytic effect of iron on low-rank coal gasification

Acid-washing low-rank coal samples were loaded with different content of iron catalyst and then pyrolyzed. FT-IR, Raman spectra, and temperature-programmed experiments were used to investigate the influence of iron on the coal char. The FT-IR results revealed that iron catalyst rises the number of –OH, –CH3, and –CH2 functional groups. The Raman spectra results showed that partial large polyaromatic ring structures transform into small polyaromatic ring structures after the addition of iron. The results of temperature-programmed desorption indicated that the number of surface active sites is increased due to the addition of iron. For low-rank coal char with 3% Fe, the number of active sites increased with the increase of adsorption temperature until 800 °C and then start to decrease. At 750 °C, the adsorption capacity of CO2 increased with the increase of time and reached saturation state after 45 min. The results of the char-steam isothermal gasification experiment suggested that the iron catalyst enhances the gasification reactivity of low-rank coal. It is verified that iron catalysts can improve the gasification reactivity of low-rank coal by increasing the number of surface active sites.

A review on transition metal oxides based nanocomposites, their synthesis techniques, different morphologies and potential applications

In the field of nanotechnology and nanoscience, transition metal oxides based nanocomposites (TMONCs) are promising for various application uses such as Supercapacitors, Sensors, Bactericidal properties, Photocatalytic Degradation, Solar Cells etc. Modification of transition metal oxide nanoparticles (TMONPs) to TMONCs by doping/mixing of another transition metal and metal oxide, carbon based nanoparticles, conducting polymers etc. to achieve enhanced surface area, increasing surface activities or number of active surface sites, reducing electron-hole recombination, increasing charge transfer processes etc. have been reported in literature. These improved properties are the possible reason for the enhancement in its practical applications efficiencies. This review summarizes recent development on transition metal oxides based nanocomposites for different potential applications. Also synthesis methods of transition metal oxide based nanocomposites have obtained an increasing attractions to achieve cost effectiveness and environment friendly routes of synthesis with high rate of production, high yield of product and also less toxic waste production. Transition metal oxides nanocomposites have been fabricated by various methods such as Microwave assisted synthesis technique, Sol-Gel method, Biosynthesis method, Co-precipitation process, Simple Chemical method etc. Different morphologies of transition metal oxides based nanocomposites have been summarized in this review article.Herein, this paper discuss about several reported synthesis techniques, various characterization techniques used for structural and surface properties identifications, different morphologies and various potential applications of transition metal oxide based nanocomposites.

Radial growth kinetics of epitaxial pyrolytic carbon layers deposited on carbon nanotube surfaces by non-catalytic pyrolysis

Chemical vapor deposition of pyrolytic carbon (PyC) onto carbon nanotube (CNT) surfaces by hydrocarbon pyrolysis can thicken the nanotube diameter until the desirable size. Vapor-induced thickening of CNTs may require no metal catalysts because the CNT-templated growth can easily convert PyC deposits into epitaxial graphene shells. However, little work has been done on the kinetics of the vapor-induced CNT thickening process during the non-catalytic pyrolysis. In this study, we discuss the growth mechanism of epitaxial PyC layers on CNT surfaces achieved by the low-pressure (≤1.5 kPa) pyrolysis of ethylene, which is distinct from previous studies using much higher gas pressures (4–100 kPa) for the PyC deposition. The average thickness of deposited PyC layers is calculated by analyzing the transmission electron microscopy images of PyC-coated CNTs. The crystallinity of PyC-coated CNTs is evaluated by Raman spectroscopy and X-ray diffraction. The thickness of PyC layers on CNT surfaces can be adjusted by simply changing the growth time under typical pyrolysis parameters (800 °C-1.5 kPa of ethylene). We find a two-stage nonlinear behavior to describe the growth kinetics of PyC layers, indicating that the radial growth rate of PyC layers can be influenced by the number of surface active sites. This study reveals the self-assembly mechanism of graphitic layers on the CNT template, which is expected to promote the diameter-controlled synthesis of CNTs.

Reversible down-regulation and up-regulation of catalytic activity of poly(N-isopropylacrylamide)-anchored gold nanoparticles

Regulating catalytic activity plays an important role in further optimizing and developing multifunctional catalysts with high selectivity and high activity. Reversible dual regulation of catalytic activity has always been a challenging task. Here, we prepared poly(N-isopropylacrylamide)-anchored gold nanoparticles (AuNP@CDs-Azo-PNIPAM) through host-guest interaction of cyclodextrin capped gold nanoparticles (AuNP@CDs) and azobenzene-terminated poly(N-isopropylacrylamide) (Azo-PNIPAM). Azo-PNIPAM as thermal and light responsive ligand allows reversible dual regulation of catalytic activity. When the temperature is higher than the lowest critical solution temperature, the PNIPAM chain shrinks rapidly, increasing the steric hindrance around AuNPs and reducing the catalytic activity. Under ultraviolet light irradiation, cis-azobenzene disassembles from cyclodextrin and the number of surface active sites of AuNPs increases, which improves the catalytic activity. The reaction rate of UV irradiation is almost 1.3 times that of visible light irradiation. This work provides a simple and effective strategy for the construction of reversible catalysts.

Number of surface sites and turnover frequencies for oxide catalysts

Unlike for metal catalysts where selective chemisorption probes (H2, O2, CO and N2O) have been successfully applied to count the number of active surface sites and allow determination of TOF values, the analogous situation for oxide catalysts has developed very slowly. The reason for the sluggish development of selective chemisorption probes for oxides is that the same chemisorption probes that work well with metals aren’t compatible with oxides since these chemical probes weakly adsorb on oxides. Methanol, however, is a very reactive molecule that has been found to readily chemisorb on oxides and allows for quantitative determination of the number of active surface sites (Ns). In this mini-review, the determination of the number of active sites by methanol chemisorption is reviewed with examples for pure oxides (one-component oxides), supported oxides (submonolayer, monolayer and above monolayer) and bulk mixed oxides (surface enriched oxide present in submonolayer, monolayer and in excess of monolayer coverages).

Size and surface-energy dependence of the adsorption/desorption equilibrium in ethanol electro-oxidation by Pd-nanoparticles. Theory and experiment.

The relation between current and voltage in the electro-oxidation of ethanol by metal nanoparticles depends on experimental parameters like the applied potential, peak potential, temperature, the electron-transfer coefficient, and the number of molecules adsorbed at active sites on the nanoparticle surface. In this form, the oxidation current depends on the ability of the nanoparticles to adsorb the ethanol molecules. Though the Laviron model well describes this phenomenology, few studies focus on the dependence of the oxidation current on the size and surface properties of the metal nanoparticles. Here, we present an experimental and theoretical study that comprises the synthesis of palladium-based nanoparticles and the generalization of the Laviron model that allows determining the dependence of the oxidation current on the size, surface energy, and adsorption–desorption properties of the nanoparticles for the ethanol oxidation. The determination of the adsorption–desorption equilibrium and the electro-oxidation current dependence with the physicochemical properties of the materials was carried out by electrochemical characterization.

Modified Catalysts and Their Fractal Properties

Obtaining high-area catalysts is in demand in heterogeneous catalysis as it influences the ratio between the number of active surface sites and the number of total surface sites of the catalysts. From this point of view, fractal theory seems to be a suitable instrument to characterize catalysts’ surfaces. Moreover, catalysts with higher fractal dimensions will perform better in catalytic reactions. Modifying catalysts to increase their fractal dimension is a constant concern in heterogeneous catalysis. In this paper, scientific results related to oxide catalysts, such as lanthanum cobaltites and ferrites with perovskite structure, and nanoparticle catalysts (such as Pt, Rh, Pt-Cu, etc.) will be reviewed, emphasizing their fractal properties and the influence of their modification on both fractal and catalytic properties. Some of the methods used to compute the fractal dimension of the catalysts (micrograph fractal analysis and the adsorption isotherm method) and the computed fractal dimensions will be presented and discussed.

Monitoring oxygen production on mass-selected iridium–tantalum oxide electrocatalysts

Development of low-cost and high-performance oxygen evolution reaction catalysts is key to implementing polymer electrolyte membrane water electrolysers for hydrogen production. Iridium-based oxides are the state-of-the-art acidic oxygen evolution reaction catalysts but still suffer from inadequate activity and stability, and iridium’s scarcity motivates the discovery of catalysts with lower iridium loadings. Here we report a mass-selected iridium–tantalum oxide catalyst prepared by a magnetron-based cluster source with considerably reduced noble-metal loadings beyond a commercial IrO2 catalyst. A sensitive electrochemistry/mass-spectrometry instrument coupled with isotope labelling was employed to investigate the oxygen production rate under dynamic operating conditions to account for the occurrence of side reactions and quantify the number of surface active sites. Iridium–tantalum oxide nanoparticles smaller than 2 nm exhibit a mass activity of 1.2 ± 0.5 kA gIr–1 and a turnover frequency of 2.3 ± 0.9 s−1 at 320 mV overpotential, which are two and four times higher than those of mass-selected IrO2, respectively. Density functional theory calculations reveal that special iridium coordinations and the lowered aqueous decomposition free energy might be responsible for the enhanced performance.

Electrospun PVDF/ZnO- Based Composite Fibers for Oil Absorption and Photocatalytic Degradation of Organic Dyes from Waste Water

The one-dimensional PVDF/ZnO composite nanofibers exhibit a large specific area, which is beneficial for the absorption of pollutants in wastewater. Moreover, the uniformly distributed ZnO nanoparticles provide a large number of reaction sites for the degradation of the organic contaminants in wastewater. The prepared multifunctional nanofiber membranes have been exploited to both dye degradation and oil absorption. This multifunctional composite nanofiber membrane are characterized and studied the photocatalytic degradation of organic pollutants. In addition, the oil absorption capacity of PVDF/ZnO composite fibers is examined using engine oil.In this work, a hydrophobic membrane was successfully prepared by incorporating ZnO nanofiller into polyvinylidene fluoride (PVDF) using an electrospinning method (Figure-1) for organic dye degradation and oil absorption applications. The hydrothermal method was used to prepare pure ZnO. The structural properties of PVDF/ZnO composite fibers and pure ZnO were studied using the X-ray diffraction technique (XRD). The crystallite size value for ZnO is calculated using Scherrer’s formula. The calculated crystallite size is 20 nm. The TEM image of pure ZnO shows a flower-like structure. The EDX spectrum shows that the ZnO sample consists of Zn and O elements. SEM images of pure PVDF and PVDF/ZnO composite electrospun mat shows uniformly oriented, interconnected structure with bead free fibers. Finally, the prepared fibers were tested for oil absorption and the photocatalytic degradation of organic dyes. Comparing the oil absorption capacity results of both pure PVDF and PVDF/ZnO, shows that the oil absorption capacity is higher for the composites with the addition of ZnO nanofiller. This is due to the addition of ZnO filler increase the hydrophobicity of the fibers. The superhydrophobic materials can allows oil to flow through and repel water. The photocatalytic activity of PVDF/ZnO was evaluated by the degradation of Azocarmine G (AZG) and Malachite green (MG) dye under sunlight irradiation. The absorption spectra shows the decrease in intensities of the absorption peak of AZG and MG dye upon the increasing of irradiation time. The results showed that 85% of AZG and 90% of MG dye could be degraded within 120 min and 240 min. When the time increases, the photodegradation efficiency also increases for the PVDF/ZnO composite fibers. The results indicate that the PVDF/ZnO composite play an vital role in AZG and MG dye degradation. The smaller crystallite size of ZnO catalyst play a key role in photocatalytic activity. As particle size decreases, the number of active surface sites increases. This in tern enhances the photocatalytic activity. The photocatalytic degradation mechanism of the PVDF/ZnO composite fiber can be explained as follows; When photon energy is irradiated on a ZnO surface, holes and electrons are formed. Superoxide radicals are formed when excited electrons in the conduction band react with adsorbed oxygen, whereas hydroxyl radicals are formed when holes in the valence band react with surface bound water molecules. Both hydroxyl and superoxide radicals have the ability to directly oxidize dye molecules. Good oil absorption efficiency (115 %) was achieved using PVDF/ZnO membrane. The results show that the prepared composite fibers can be used to absorb oil and degrade organic contaminants. This cost-effective, easy operation, reusability, and efficiency of the PVDF/ZnO fiber mats could be potentially useful for water treatment and oil recovery. Figure 1

Potential Co-catalyst application of novel M3P2 (M=Zn, Cd) in photocatalytic hydrogen evolution reaction from water splitting

New noble-metal-free co-catalysts based on transition metal phosphides, Zn3P2 and Cd3P2, were fabricated and loaded on hetero-structure of BiFeO3–CdWO4 with the aim of promoting hydrogen evolution from water splitting without using sacrificial agent. The opto-electrochemical properties of the photocatalysts were investigated by various characterization techniques and it was observed that the co-catalyst loaded BiFeO3–CdWO4 exhibited better light harvestability, charge separation efficiency and charge mobility. The photocatalytic hydrogen productivity reached up to 572.81 μmol h−1.gcat−1 h by loading 12 wt% Zn3P2 and 488.25 μmol h−1.gcat−1 by loading 9 wt% Cd3P2 over BiFeO3–CdWO4. Zn3P2 and Cd3P2 have shown light absorption in visible to near IR region, thus they may also have the additional role of a photocatalyst other than being active sites for the photocatalytic reduction half-reaction. Loading the co-catalysts also resulted in multiplication of specific surface area which means an increase in the number of surface active sites. We observed a higher hydrogen productivity with lower photocatalytic rate by loaded Zn3P2 in compared with Cd3P2. This is attributed to the different photoresponsivity and band edge energy of the co-catalysts. The details of charge transfer mechanism between the host hetero-structure photocatalyst and loaded co-catalysts has been discussed.

Development of hollow δ-FeOOH structures for mercury removal from water

Abstract δ-FeOOH, a magnetic iron oxyhydroxide, has a significant number of -OH groups on its surface. These provide an attractive platform for heavy metal species in contaminated water, giving it potential as an adsorbent. Its performance can be improved by increasing the number of active surface sites. δ-FeOOH hollow structures were synthesized on a mesoporous silica surface then treated with NaOH solution. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed that structure synthesis was successful. δ-FeOOH, 5,27 nm, hollow crystals were produced with 63 m2 g−1 surface area and 20 nm average pore size. The point of zero charge was 4.72, which is beneficial for Hg(II) adsorption near neutral pH. The maximum Hg(II) adsorption capacity at pH 7 was determined as 89.1 mg g−1. The kinetics data were best fitted by a pseudo-second-order model with k2 equal 0,1151 g mg−1min−1. Finally, a nanomaterial filter was developed and used to remove mercury in water samples from a Brazilian river.

Inductive effects in cobalt-doped nickel hydroxide electronic structure facilitating urea electrooxidation

Electrochemical oxidation of urea provides an approach to prevent excess urea emissions into the environment while generating value by capturing chemical energy from waste. Unfortunately, the source of high catalytic activity in state-of-the-art doped nickel catalysts for urea oxidation reaction (UOR) activity remains poorly understood, hindering the rational design of new catalyst materials. In particular, the exact role of cobalt as a dopant in Ni(OH)2 to maximize the intrinsic activity towards UOR remains unclear. In this work, we demonstrate how tuning the Ni:Co ratio allows us to control the intrinsic activity and number of active surface sites, both of which contribute towards increasing UOR performance. We show how Ni90Co10(OH)2 achieves the largest geometric current density due to the increase of available surface sites and that intrinsic activity towards UOR is maximized with Ni20Co80(OH)2. Through density functional theory calculations, we show that the introduction of Co alters the Ni 3d electronic state density distribution to lower the minimum energy required to oxidize Ni and influence potential surface adsorbate interactions.

Investigation of morphologically tuned Sb2S3 nanostructures as an effective electrocatalyst for hydrogen evolution reaction

A simple solvothermal route has been adopted for the successful development of morphologically varied Sb2S3 nanostructures by incorporating various organic complex reagents into the reaction process. The prepared Sb2S3 nanostructures were investigated for electrocatalytic performance towards HER. The nanostructured Sb2S3 (PVP) catalyst exhibiting dumbbell shape formed together by the aggregation of nanowires revealed better performance in catalyzing HER with low overpotential of − 0.168 V vs. RHE in attaining the current density of 10 mA/cm2 when compared with other catalyst possessing different morphology. It also revealed least Tafel slope value of 85 mV/dec corroborating that the reaction kinetics follows Volmer-Heyrovsky step. The nanowires possess large number of active surface sites and interfaces as it facilitates transfer of charges across the electrode-electrolyte interface which helped in the evolution of hydrogen molecules more rapidly with low onset potential.

Role of transition-metal electrocatalysts for oxygen evolution with Si-based photoanodes

A comprehensive understanding of the role of the electrocatalyst in photoelectrochemical (PEC) water splitting is central to improving its performance. Herein, taking the Si-based photoanodes (n+p-Si/SiOx/Fe/FeOx/MOOH, M = Fe, Co, Ni) as a model system, we investigate the effect of the transition-metal electrocatalysts on the oxygen evolution reaction (OER). Among the photoanodes with the three different electrocatalysts, the best OER activity, with a low-onset potential of ∼1.01 VRHE, a high photocurrent density of 24.10 mA cm−2 at 1.23 VRHE, and a remarkable saturation photocurrent density of 38.82 mA cm−2, was obtained with the NiOOH overlayer under AM 1.5G simulated sunlight (100 mW cm−2) in 1 M KOH electrolyte. The optimal interfacial engineering for electrocatalysts plays a key role for achieving high performance because it promotes interfacial charge transport, provides a larger number of surface active sites, and results in higher OER activity, compared to other electrocatalysts. This study provides insights into how electrocatalysts function in water-splitting devices to guide future studies of solar energy conversion.

Key factors that affect catalytic activity of activated carbon-based catalyst in chemical looping methane decomposition for H2 production

Chemical looping methane decomposition for hydrogen production is widely discussed, and activated carbon (AC) is widely studied as a cheap, easily-available catalyst with high initial activity. In this study, 10%, 30% and 50% HNO3 was used to treat AC to change its specific surface area, pore structure, and surface functional groups. After reactions at 900 °C and 950 °C, the AC is characterized and analyzed, and key factors affecting its catalytic performance are assessed. After acid treatment, the specific surface areas and pore volumes of AC are decreased, the number of oxygen-containing and nitrogen-containing functional groups is increased. It may be expected that increases of functional groups would increase the number of active surface sites, however, experiments have shown surface areas and pore volumes are representative and perhaps linearly correlated with methane conversions. The decreases in surface areas and pore volumes are predominantly associated with the elimination of micropores. Simultaneously, conclusions from molecular simulations are that smaller pore sizes in AC promotes adsorption of methane molecules on the AC and their conversion to hydrogen. Therefore, the unfavorable influences of decreased specific surface area and changed pore structure are detrimental to the initial steps of methane adsorption and then decomposition.

Experimental methods in chemical engineering: Temperature programmed surface reaction spectroscopy—TPSR

AbstractTemperature programmed surface reaction spectroscopy (TPSR) is a powerful technique to determine the surface chemistry of bulk metal, supported metal, bulk metal oxide, supported metal oxide, zeolite, and molecular sieve catalysts. It can provide both qualitative and quantitative analysis of the surface active sites present on the catalyst surface, the reaction mechanisms, and kinetics occurring on the catalyst surface by using chemical probe molecules such as alcohols, carboxylates, and specific acidic‐basic reacting gases. In this tutorial review, the highly informativeCH3OHchemical probe molecule was used to highlight the information that can be obtained fromCH3OH‐TPSR experiments. TheCH3OHmolecule readily interacts with the catalyst surface to form surfaceCH3O·andHCOO·intermediates that react to produce HCHO/HCOOCH3/(CH3O)2CH2,CH3OCH3, andCO/CO2products related to the surface redox, acid and basic nature, respectively. Integration of theCH3OH‐TPSR spectra peaks provide the number of surface active sites. The surface kinetic information provided byCH3OH‐TPSR allows to discriminate between different reaction mechanisms (first‐order, second‐order, Langmuir‐Hinshelwood, and Mars‐van Krevelen). We discuss the uncertainty inherent inCH3OH‐TPSR experiments and address source of errors and detection limits. Web of Science indexed over 800 articles citing TPSR since 1990. A bibliometric analysis identified four clusters of reactions and catalysts: the dominant catalysts for partial oxidation and water gas shift were Ni, Ru, and Pt;CeO2, Co, Cu, Rh, Pd, and perovskites were the main catalysts for combustion and hydrogenation; Ag and zeolites were grouped with reduction; and,Al2O3,ZrO2,SiO2, andV2O5were applied for dehydrogenation.

Ultrasensitive NO2 gas sensor based on Sb-doped SnO2 covered ZnO nano-heterojunction

Sb-doped SnO2 covered ZnO nano-heterojunction (Sb-doped SnO2/ZnO NHs) are prepared by using a microwave hydrothermal method. The effect about morphology and gas sensor performance of the SnO2/ZnO NHs with Sb-doping is studied in detail. The SEM indicated that the morphology of SnO2 changed from nanowires to nanosheets by Sb-doping and the growth direction of SnO2 was vertical to the plane of ZnO from the TEM. Compared with undoped SnO2/ZnO NHs, the gas sensor response became higher as the concentration of Sb-doping increased which shows the sensor performance can be enhanced by Sb-doped SnO2. The change of morphology by Sb-doping increased the number of surface active sites and defects. In addition, a certain concentration of O vacancy was induced by Sb-doping to provide more free electrons that can also be captured by NO2. The research may provide a reference for studying the effect of Sb-doped composite materials and gas sensor performance.

Exploring halloysite nanotubes as catalyst support for methane combustion: Influence of support pretreatment

Catalytic combustion of methane is considered an environmentally friendly route for energy generation owing to the high H/C ratio of methane and low CO2 emissions compared to other hydrocarbons fuels. The utilization of heterogeneous catalysts permits combustion at lower temperatures compared with thermal combustion. Herein, we developed new catalysts of palladium-supported halloysite nanotubes (HNTs) for methane combustion. This was performed via chemical modification of HNTs using four different species i.e. H2SO4 (HNTs-H2SO4), NaOH (HNTs-NaOH), sodium dodecyl sulfate (HNTs-SDS), and cetyltrimethylammonium bromide (HNTs-CTAB). After chemical modification, Pd was deposited on the pretreated HNTs and the impact of chemical treatment on the morphology, crystal structure, textural properties, and methane oxidation activity was studied. All catalysts based on chemically modified HNTs exhibited enhanced catalytic performance towards methane combustion compared to Pd-supported on pristine HNTs, in particular, Pd/alkali-treated HNTs (Pd/HNTs-NaOH) revealed the highest catalytic activity towards methane combustion with the temperature of complete conversion (T100) equals 385 °C and activation energy of 79.15 kJ mol−1. Furthermore, the same sample displayed enhanced stability compared to other counterparts. This was assigned to the confinement of Pd nanoparticles at the inner surface which enhances the catalyst-support interaction, increases the number of surface active sites, and enhances the resistance to sintering at high temperatures.

Experimental and Theoretical Investigations into the Performance and Mechanism of CO2 Capture by 3D and 2D ZnAl Layered Double Hydroxides.

Two-dimensional (2D) materials have a wide range of applications in adsorption and catalysis because of their high specific surface areas and large number of surface active sites. In this paper, bulk ZnAl layered double hydroxides (ZnAl-LDHs or bulk-LDHs) and 2D monolayer ZnAl-LDHs (monolayer-LDHs) were constructed and used for CO2 capture at temperatures of 298-573 K. The experimental results show that monolayer-LDHs have a large specific surface area (455 m2 g-1) and shows an excellent CO2 capture performance (4.5 mmol g-1). The CO2 adsorption capacity of monolayer-LDHs decreases greatly with an increase of the temperature, while bulk-LDHs are less affected by the temperature. Moreover, the parameters of charge distribution, density of states, and charge transfer of bulk-LDHs and monolayer-LDHs were studied in detail by density functional theory, and the difference of the adsorption mechanism between two LDH materials in CO2 capture was compared. It is found that monolayer-LDHs have better electronic activity than bulk-LDHs. At low temperature, CO2 is more likely to be physically adsorbed on the surface of monolayer-LDHs, and the adsorption process is more likely to occur. CO2 is more easily adsorbed on the surface of bulk-LDHs in the form of chemisorption, the adsorption energy is larger (-1.01 eV), but the CO2 capture capacity is quite stable at high temperature.

Morphologically tailored CuO nanostructures toward visible-light-driven photocatalysis

Nanostructures of transition metal oxides, such as copper oxide (CuO), are attractive for their stability and cost-effectiveness. This work reveals that the precursor materials play a crucial role in tailoring the morphologies, properties of CuO nanostructures. Herein, three different copper precursors, such as copper acetate, copper chloride, and copper nitrate, have been used to prepare CuO nanostructures. We find that nanosphere morphology is formed when copper acetate and copper chloride are used, whereas nanoflower morphology is formed when copper nitrate is used as precursors. The synthesis of flower-like CuO nanostructures is attained by altering the precursor material alone, and the petals of these flowers have a thickness of around 50 nm. The photocatalytic properties of the CuO nanoparticles prepared with the different precursors are investigated for the degradation of methylene blue dye. At a certain dye concentration level, the small size of particles results in a higher surface-to-volume ratio, which causes an increase in the number of active surface sites. Owing to the lowest particle size, CuOsphere-A (copper acetate) performs the best photodegradation efficiency. Additionally, the nanoflower-like structure could provide better accessibility of the reactants on the surface of photocatalytic material, resulting in more favorable for the photodegradation.