Synergistic Enhancement of CO2 photoreduction through sulfur defects in (3D/2D) CdS-nanoflowers/CN Binary heterojunction photocatalyst under visible light.

Global warming is the biggest threat to the entire world owing to the continuous release of greenhouse gases such as CO2 from various sources. Herein, we have utilized renewable energy for the conversion of CO2 to valuable feedstocks through a semiconductor-mediated photocatalytic system. The cadmium sulfide nanoflowers (CS-NFs) decorated graphitic carbon nitride (CN) through a solvothermal route to form a Z-scheme CSCN heterojunction. The as-synthesized material has been characterized by various spectroscopic and microscopic tools. The optimal CSCN-0.5 (1:0.5) photocatalyst achieves a CO production rate of 130.9 µmol g-1 under visible light irradiation of 4h (λ > 420 nm), doubling that of pristine CS-NFs and CN. CO, along with CH4 (3.4 µmol g-1) and C2H6 (2.9 µmol g-1), is the sole product detected. Experimental results indicate that the CSCN-0.5 photocatalyst spatially separates electron-hole pairs, suppresses charge carrier recombination, and maintains robust redox ability, enhancing CO2 photoreduction. The CO2 reduction mechanism over CSCN heterojunction was also studied through in-situ DRIFTS and electron spin resonance (ESR) measurements. Therefore, CSCN proves that it could be used as a robust photocatalyst for the CO2 reduction reactions towards C1 and C2 feedstocks.

Electronic Structure of Mg-, Si-, and Zn-Doped SnO2 Nanowires: Predictions from First Principles.

We investigated the electronic structure of Mg-, Si-, and Zn-doped four-faceted [001]- and [110]-oriented SnO2 nanowires using first-principles calculations based on the linear combination of atomic orbitals (LCAO) method. This approach, employing atomic-centered Gaussian-type functions as a basis set, was combined with hybrid density functional theory (DFT). Our results show qualitative agreement in predicting the formation of stable point defects due to atom substitutions on the surface of the SnO2 nanowire. Doping induces substantial atomic relaxation in the nanowires, changes in the covalency of the dopant-oxygen bond, and additional charge redistribution between the dopant and nanowire. Furthermore, our calculations reveal a narrowing of the band gap resulting from the emergence of midgap states induced by the incorporated defects. This study provides insights into the altered electronic properties caused by Mg, Si, and Zn doping, contributing to the further design of SnO2 nanowires for advanced electronic, optoelectronic, photovoltaic, and photocatalytic applications.

Crystallinity and lattice vacancies of different mesoporous g-C3N4 for photodegradation of tetracycline and its cytotoxic implication.

Tetracycline (TC) antibiotic removal from water bodies is important to provide clean water and sanitation. Mesoporous graphitic carbon nitride (GCN) photocatalyst derived from three different types of precursors manages to remove TC effectively under visible light irradiation. Among urea, thiourea, and melamine precursors, melamine-prepared GCN (MGCN) via thermal polymerization has the highest efficiency to photodegrade tetracycline (TC) antibiotics up to 99.5% (0.0122 min-1) within 240 min. The COD for TC removal by using MGCN was up to 77.5% after 240 min of degradation. This is due to the slow charge recombination and rapid charge carrier migration. The MGCN encounters different properties such as high crystallinity, dense structure allowing fast charges migration, and nitrogen vacancies that create a defect state that suppresses charge recombination. It was found that the conduction band (CB) of MGCN was located at a more negative position (ECB = -0.33 V) than (O2/O2•-) and the valence band (VB) was placed at a more positive position (EVB = 2.30 V) than (H2O/OH•), which allows generation of both radicals for photodegradation. Based on the cell viability test, the photodegraded TC in the water how non-toxicity toward Balb/c 3T3 cells after being irradiated (λ > 420 nm) for 240 min under visible light. The MGCN prepared in this study demonstrated the highest effectiveness and recyclable photocatalyst for the removal of TC among all GCNs.

Highly Efficient Photothermal Reduction of CO2 on Pd2Cu Dispersed TiO2 Photocatalyst and Operando DRIFT Spectroscopic Analysis of Reactive Intermediates.

The photocatalytic conversion of CO2 to fuels using solar energy presents meaningful potential in the mitigation of global warming, solar energy conversion, and fuel production. Photothermal catalysis is one promising approach to convert chemically inert CO2 into value-added chemicals. Herein, we report the selective hydrogenation of CO2 to ethanol by Pd2Cu alloy dispersed TiO2 (P25) photocatalyst. Under UV-Vis irradiation, the Pd2Cu/P25 showed an efficient CO2 reduction photothermally at 150 °C with an ethanol production rate of 4.1 mmol g-1 h-1. Operando diffuse reflectance infrared Fourier transform (DRIFT) absorption studies were used to trace the reactive intermediates involved in CO2 hydrogenation in detail. Overall, the Cu provides the active sites for CO2 adsorption and Pd involves the oxidation of H2 molecule generated from P25 and C-C bond formation.

In-situ preparation of CuO nanoparticles decorated In2O3 pn heterojunction composite for the photoelectrochemical detection of ornidazole.

The eco-friendly synthesis of metal oxides pn junction composite with high visible light absorption and its photoelectrochemical monitoring on antibiotics is reported. The In2O3-CuO pn heterojunction composite was successfully prepared by in-situ hydrothermal decoration of CuO on the prepared In2O3 using a simple reflux method. The obtained nanorods like In2O3-CuO pn heterojunction exhibited high conductivity with excellent stability for the facilitated photoelectrochemical detection of ornidazole (ONZ) that plays a role in aquatic toxicology. The photo-stability and optical characteristics of the In2O3-CuO heterojunction composite were analyzed through photocurrent and UV-visible studies. Mechanism of ONZ signaling has been proposed with appropriate band levels derived by Mott-Schottky analysis. An optimized In2O3-CuO heterojunction detects ONZ in the range 0.05-65.3 nM with 0.0092 nM as the limit of detection at - 0.45 V (vs. Ag/AgCl) working potential. The practical applicability of the sensor device was tested in chicken meat, human urine, and lake water samples containing ONZ. The recoveries of real samples were above 95% and results obtained were compared with electrochemical methods.

Highly Mesoporous g-C3N4 with Uniform Pore Size Distribution via the Template-Free Method to Enhanced Solar-Driven Tetracycline Degradation.

A highly mesoporous graphitic carbon nitride g-C3N4 (GCN) has been produced by a template-free method and effectively photodegrade tetracycline (TC) antibiotic under solar light irradiation. The mesoporous GCN (GCN-500) greatly improves the photoactivity (0.0247 min-1) by 2.13 times, as compared to that of bulk GCN (0.0116 min-1). The efficiently strengthened photoactivity is ascribed to the high porosity (117.05 m2/g), and improves the optical absorption under visible light (Eg = 2.65 eV) and good charge carrier separation efficiency. The synthesized mesoporous GCN shows a uniform pore size (~3 nm) distribution. GCN-500 shows large pore volume (0.210 cm3/g) compared to GCN-B (0.083 cm3/g). Besides, the GCN-500 also exhibits good recyclability and photostability for TC photodegradation. In conclusion, GCN-500 is a recyclable photocatalyst for the removal of TC under visible light irradiation.

Operando Investigation of Structural and Chemical Origin of Co3O4 Stability in Acid under Oxygen Evolution Reaction.

Replacement of an expensive anode electrocatalyst in proton exchange membrane water electrolysis is of great importance. Recently explored Co3O4 shows good activity and stability toward oxygen evolution reaction (OER) in acid; however, the stability is not adequately explained. Lack of such information delays the design of an acid-stable OER electrocatalyst. Here, we investigate the structural origin of cobalt dissolution by various local atomic configurations of Co3O4. Operando Raman studies and voltammetric data reveal that chemical reduction of the CoO2 intermediate accompanied by lattice oxygen loss leads to undercoordinated CoO sites, which then react with water and form an amorphous three-dimensional (3D) porous network of CoO(OH)x, called the hydrous oxide layer (HOL). Growth of HOL mainly depends on the oxygen vacancies and near-surface OI- that impair the crystalline integrity and favor dissolution. These insights provide a fundamental relation between OER activity and stability and offer a specific guideline for the electrocatalyst design.

Morphology-Controlled Synthesis of α-Fe2O3 Nanocrystals Impregnated on g-C3N4-SO3H with Ultrafast Charge Separation for Photoreduction of Cr (VI) Under Visible Light.

Surface functionalization and shape modifications are the key strategies being utilized to overcome the limitations of semiconductors in advanced oxidation processes (AOP). Herein, the uniform α-Fe2O3 nanocrystals (α-Fe2O3-NCs) were effectively synthesized via a simple solvothermal route. Meanwhile, the sulfonic acid functionalization (SAF) and the impregnation of α-Fe2O3-NCs on g-C3N4 (α-Fe2O3-NCs@CN-SAF) were achieved through complete solvent evaporation technique. The surface functionalization of the sulfonic acid group on g-C3N4 accelerates the faster migration of electrons to the surface owing to robust electronegativity. The incorporation of α-Fe2O3-NCs with CN-SAF significantly enhances the optoelectronic properties, ultrafast spatial charge separation, and rapid charge transportation. The α-Fe2O3-HPs@CN-SAF and α-Fe2O3-NPs@CN-SAF nanocomposites attained 97.41% and 93.64% of Cr (VI) photoreduction in 10 min, respectively. The photocatalytic efficiency of α-Fe2O3-NCs@CN-SAF nanocomposite is 2.4 and 2.1 times higher than that of pure g-C3N4 and α-Fe2O3, respectively. Besides, the XPS, PEC and recycling experiments confirm the excellent photo-induced charge separation via Z-scheme heterostructure and cyclic stability of α-Fe2O3-NCs@CN-SAF nanocomposites.

One-pot sonochemical synthesis of CuS nanoplates decorated partially reduced graphene oxide for biosensing of dopamine neurotransmitter.

The sonochemical methods have been used as a straight forward method for the synthesis of various composite materials, including the transition metal dichalcogenide composites. In the present work, we report a simple sonochemical synthesis of CuS nanoplates decorated partially reduced graphene oxide (PrGO) nanocomposite for the first time. The PrGO-CuS nanocomposite was synthesized using bath-sonication (frequency: 37 kHz; power: 150 W) of graphene oxide (GO), and CuS precursors at 80 °C for 60 min. The physicochemical characterization (FESEM, XRD, FTIR, and Raman spectroscopy) results confirmed the successful formation of CuS nanoplates on PrGO nanosheets. The as-synthesized PrGO-CuS nanocomposite was further utilized for electroanalysis of dopamine neurotransmitter. The obtained electroanalytical results revealed that PrGO-CuS nanocomposite has superior electrochemical activity towards dopamine than those obtained for GO, CuS, and GO-CuS composite. The fabricated biosensor shows a lower limit of detection (0.022 µM) with a more comprehensive linear response range (0.1-155.1 µM) for the detection of dopamine. Moreover, the PrGO-CuS nanocomposite electrode was successfully used for the detection of dopamine in bovine serum albumin.

Studies on the sonochemical polymorphism of Sb2O3 on activated graphite for the electrochemical determination of imipramine.

This work reports the simultaneous sonochemical activation of graphite and sonohydrolysis of antimony chloride (SbCl3) in the alkaline medium. The experiments conducted by bath sonicator operated at 37 kHz of frequency and a maximum power of 150 W. The simple sonohydrolysis of SbCl3 alone produced an orthorhombic phase of Sb2O3, whereas, it produced mixed phases of cubic and orthorhombic Sb2O3 when introduced with graphite. Herein, the activated graphite (aGR) provides the best support to the growth of cubic phase. This cubic Sb2O3 is grown only on the graphite basal planes, which confirmed by scanning electron microscope. Moreover, the phase changes have identified by the X-ray diffraction, Raman and X-ray photoelectron analysis. The prepared aGR-Sb2O3 composite has applied to the electroanalytical studies of anti-depressant drug imipramine (IMP). The results showed that aGR-Sb2O3 revealed better activity than Sb2O3; the reasons are discussed comprehensively. Furthermore, aGR-Sb2O3 exhibited comparable analytical results for the determination of IMP.

In-situ DRIFT investigation of photocatalytic reduction and oxidation properties of SiO2@α-Fe2O3 core-shell decorated RGO nanocomposite.

In this work, SiO2@α-Fe2O3 core-shell decorated RGO nanocomposites were prepared via a simple sol-gel method. The nanocomposites were prepared with different weight percentages (10, 30, and 50 wt %) of the SiO2@α-Fe2O3 core-shell on RGO, and the effects on the structural and optical properties were identified. The photocatalytic reduction and oxidation properties of the nanocomposites in the gas phase were assessed through the reduction of CO2 and oxidation of ethanol using in-situ diffuse-reflectance infrared fourier transform spectroscopy (DRIFT). The prepared nanocomposite with (30 wt %) of SiO2@α-Fe2O3 showed superior photocatalytic activity for the gas phase reduction of CO2 and oxidation of ethanol. Enhancement in the activity was also perceived when the light irradiation was coupled with thermal treatment. The DRIFT results for the nanocomposites indicate the active chemical conversion kinetics of the redox catalytic effect in the reduction of CO2 and oxidation of ethanol. Further, the evaluation of photoelectrochemical CO2 reduction performance of nanocomposites was acquired by linear sweep voltammetry (LSV), and the results showed a significant improvement in the onset-potential (-0.58 V) for the RGO (30 wt %)-SiO2@α-Fe2O3 nanocomposite.

Sonochemical synthesis and anchoring of zinc oxide on hemin-mediated multiwalled carbon nanotubes-cellulose nanocomposite for ultra-sensitive biosensing of H2O2.

In this work, the metal oxide and biopolymer nanocomposites on multiwalled carbon nanotubes (MWCNT) were prepared using a simple sonochemical method. The hexagonal nanorods of zinc oxide (ZnO NR) were synthesized by probe sonication (frequency = 20 kHz, amplitude = 50) method and were integrated on ultrasonically functionalized MWCNT-cellulose nanocrystals (MWCNT-CNC) for the first time. The stable hemin bio-composites also were prepared using the bath sonication (37 kHz of frequency, 150 W of power) method, and was used for the selective and ultrasensitive electrochemical detection of H2O2. The UV-Vis spectroscopy studies confirmed the presence of native hemin on MWCNT-CNC/ZnO NR nanocomposite. Cyclic voltammetry studies revealed that an enhanced redox electrochemical behaviour of hemin was observed on hemin immobilised MWCNT-CNC/ZnO NR nanocomposite than that of other hemin modified electrodes. Also, the MWCNT-CNC/ZnO NR/hemin modified SPCE showed 2.3 folds higher electrocatalytic activity with a lower reduction potential (-0.2 V) towards H2O2 than that of other investigated hemin modified electrodes including hemin/MWCNT and hemin/CNC-ZnO. The fabricated biosensor displayed a stable amperometric response (-0.2 V vs Ag/AgCl) in the linear concentration of H2O2 ranging up to 4183.3 µM with a lower detection limit of 4.0 nM.

Tin disulfide nanorod-graphene-ß-cyclodextrin nanocomposites for sensing dopamine in rat brains and human blood serum.

In the present work describes a facile synthesis of tin disulfide (SnS2) nanorods decorated graphene-ß-cyclodextrin (SnS2/GR-ß-CD) nanocomposite for robust and novel dopamine (DA) electrochemical biosensor applications. The DA biosensor was fabricated using the glassy carbon electrode (GCE) modified with SnS2/GR-ß-CD nanocomposite. The sonochemical and hydrothermal methods have been used for the synthesis of SnS2/GR-ß-CD. Different physicochemical methods were used to confirm the formation of the GR-ß-CD, SnS2, and SnS2/GR-ß-CD nanocomposite. The cyclicvoltammetric cathodic current response of DA was 5 folds higher than those observed at bare, ß-CD, SnS2-ß-CD, and GR-ß-CD modified GCEs. Under optimised conditions, the biosensor's DPV response current is linear to DA from the concentration of 0.01-150.76 µM. The detection limit of the biosensor was 4 nM. The SnS2/GR-ß-CD biosensor shows an excellent selectivity towards DA in the presence of common interfering species, including ascorbic acid and uric acid. Also, the as-prepared nanocomposite-modified electrode exhibited satisfactory long-term stability, sensitivity (2.49 µAµM-1 cm-2) along with reusability for detection of DA. The fabricated SnS2/GR-ß-CD biosensor was successfully used for the detection of DA in the rat brain and human blood serum samples.

Sonochemical synthesis of gum guar biopolymer stabilized copper oxide on exfoliated graphite: Application for enhanced electrochemical detection of H2O2 in milk and pharmaceutical samples.

A novel and cost-effective synthesis of biopolymer-based organic and inorganic composite materials have received substantial attention in a broad range application including electroanalysis of small molecules. In this perspective, we report the synthesis of gum guar (guar) biopolymer stabilized cupric oxide decorated on exfoliated graphite (GR-guar/CuO) composite. Different physicochemical characterization methods were used to confirm the successful exfoliation of graphite and formation of the GR-guar/CuO composite. A simple sonochemical method has been used for the preparation of guar stabilized exfoliated graphite (GR-guar). The flower-like CuO on GR-guar and guar stabilized CuO (CuO-guar) composites were synthesized using a hydrothermal method. Cyclic voltammetric studies revealed that the GR-guar/CuO composite modified screen-printed carbon electrode (SPCE) had enhanced electro-reduction ability towards H2O2 than GR-guar and pristine graphite/CuO-guar modified SPCEs. Under optimized experimental conditions, the GR-guar/CuO composite modified electrode detects H2O2 in the response ranges from 0.02 to 1296.6 µM. The sensor shows a lower detection limit of 5.8 nM with high sensitivity. The as-prepared GR-guar/CuO composite sensor is highly reproducible and had excellent selectivity and practicality towards the detection of H2O2. Consequently, the fabricated sensor can be used for the accurate detection of H2O2 in real samples.

Effect of cavitation erosion in the sonochemical exfoliation of activated graphite for electrocatalysis of acebutolol.

This study mainly covered the cavitation erosion in probe sonication and its electrochemical behavior. The activated graphite was exfoliated by the probe sonication wherein the titanium alloy (TA) is used as a probe (micro-tip). The sonication performed in the aqueous solution contains a mixture of sulfuric acid and nitric acid (1:1). The exfoliated graphite (EG) was examined by field emission scanning electron microscope, Raman and X-ray diffraction pattern analysis. The results showed that some TA particles dissolute from the TA micro-tip accompanied with graphite exfoliation. This dissolution experienced from the cavitation erosion, because the acoustic cavitation makes severe deformation on probe tips due to the bubble collapse. The dissolution rate increased when increasing sonication time; the resultant TA particles are randomly distributed over the EG. These EGTAs applied to the electrochemical oxidation of acebutolol which revealed an appreciable electrochemical performance and also exhibited better analytical performances to the electrochemical determinations. The obtained analytical parameters viz., sensitivity (0.234 µA µM-1 cm-2), linear range (0.01-15.1 µM), and limit of detection (0.003 µM) are highly comparable with the previous reports. Moreover, it has an acceptable tolerance with the interfering substances.

Undoped and Eu3+ Doped Magnesium-Aluminium Layered Double Hydroxides: Peculiarities of Intercalation of Organic Anions and Investigation of Luminescence Properties.

The Mg3/Al and Mg3/Al0.99Eu0.01 layered double hydroxides (LDHs) were fabricated using a sol-gel chemistry approach and intercalated with different anions through ion exchange procedure. The influence of the origin of organic anion (oxalate, laurate, malonate, succinate, tartrate, benzoate, 1,3,5-benzentricarboxylate (BTC), 4-methylbenzoate (MB), 4-dimethylaminobenzoate (DMB) and 4-biphenylacetonate (BPhAc)) on the evolution of the chemical composition of the inorganic-organic LDHs system has been investigated. The obtained results indicated that the type and arrangement of organic guests between layers of the LDHs influence Eu3+ luminescence in the synthesized different hybrid inorganic⁻organic matrixes. For the characterization of synthesis products X-ray diffraction (XRD) analysis, infrared (FTIR) spectroscopy, fluorescence spectroscopy (FLS), and scanning electron microscopy (SEM), were used.

Facile synthesis of cellulose microfibers supported palladium nanospindles on graphene oxide for selective detection of dopamine in pharmaceutical and biological samples.

The cost-effective synthesis of novel functional nanomaterials has received significant attention in the physical and chemical sciences due to their improved surface area, high catalytic activity along with unique morphological features. This paper reports a facile and eco-friendly synthesis of spindle-like palladium nanostructures (PdSPs) on graphene oxide-cellulose microfiber (GO-CMF) composite for the first time. The GO-CMF/PdSPs composite was synthesized by an electrochemical method without the use of additional surfactants and capping agents. The synthesized materials were characterized and confirmed by using transmission electron microscopy, high-resolution scanning electron microscopy, X-ray diffraction spectroscopy, Raman spectroscopy and Fourier-transform infrared spectroscopy. As-synthesized GO-CMF/PdSPs composite modified electrode was used as a selective electrocatalyst for the oxidation of dopamine (DA). The electrochemical redox behaviors of DA were investigated using cyclic voltammetry (CV). The CV results revealed that the GO-CMF/PdSPs composite modified electrode has 10 folds enhanced oxidation current response to DA than GO, PdSPs and GO-CMF modified GCEs. Under optimized conditions, the GO-CMF/PdSPs composite sensor exhibits a linear response to DA in the concentration range from 0.3 to 196.3 µM with the lower detection limit of 23 nM. The nanocomposite electrode also shows promising features towards the reliable and selective detection of DA, which includes high stability, reproducibility and high selectivity towards the commonly interfering species such as ascorbic acid, uric acid, and dihydroxybenzene isomers. The sensor was successfully tested for the real-time detection of DA in the commercial DA injections and human serum samples.

Novel electrochemical synthesis of cellulose microfiber entrapped reduced graphene oxide: A sensitive electrochemical assay for detection of fenitrothion organophosphorus pesticide.

Over the past decades, the synthesis of carbohydrate polymers incorporated graphene or reduced graphene oxide has received greater attention in different disciplines owing to their unique physicochemical properties. In this context, we report a facile electrochemical synthesis of cellulose microfibers supported reduced graphene oxide and its application towards enhanced and lower potential electrochemical detection of fenitrothion. The synthesized cellulose microfibers supported reduced graphene oxide composite was further characterized using Fourier-transform infrared spectroscopy, Raman spectroscopy and high resolution scanning electron microscopy. Cyclic voltammetry studies reveal that cellulose microfibers supported reduced graphene oxide composite modified screen-printed carbon electrode exhibits a superior electro-reduction ability and lower reduction potential towards fenitrothion compared to screen-printed carbon electrodes modified with graphene oxide, graphene oxide-cellulose microfibers, and reduced graphene oxide. Furthermore, cellulose microfibers supported reduced graphene oxide composite modified electrode showed 141 mV lower reduction potential towards fenitrothion than the chemically reduced graphene oxide- cellulose microfibers composite modified screen-printed carbon electrode. The effect of accumulation time, catalyst loading, scan rate and pH for the detection of fenitrothion has been studied and discussed. Differential pulse voltammetric studies show that the fabricated composite electrode can detect the fenitrothion in a wider linear response range up to 1.134 mM with a detection limit of 8 nM. To validate the proof of concept, the fabricated sensor was successfully applied for the detection of fenitrothion in different water samples.

Enhanced reversible redox activity of hemin on cellulose microfiber integrated reduced graphene oxide for H2O2 biosensor applications.

In recent years, the carbohydrate polymers incorporated composite materials have shown significant interest in the bioanalytical chemistry due to their enhanced catalytic performances of various enzymes or mimics. This paper reports the fabrication of novel H2O2 biosensor using a hemin immobilized reduced graphene oxide-cellulose microfiber composite (hemin/RGO-CMF). The RGO-CMF composite was prepared by the reduction of GO-CMF composite using vitamin C as a reducing agent. Various physio-chemical methods have applied for the characterization of RGO-CMF composite. Cyclic voltammetry results revealed that the hemin/RGO-CMF composite shows a better redox electrochemical behavior than hemin/RGO and hemin/GO-CMF. Under optimized conditions, the hemin/RGO-CMF composite exhibit a linear response to H2O2 in the concentration range from 0.06 to 540.6 µM with the lower detection limit of 16 nM. The sensor also can able to detect the H2O2 in commercial contact lens solution and milk samples with functional recovery, which authenticates the potential ability in practical sensors.

Novel electrochemical synthesis of copper oxide nanoparticles decorated graphene-ß-cyclodextrin composite for trace-level detection of antibiotic drug metronidazole.

Over the past decades, the synthesis of inorganic and organic nanocomposites has received much attention in the range of fields including electroanalysis of organic chemicals. In this regard, we have prepared copper oxide nanoparticle (CuO NPs) decorated graphene/ß-cyclodextrin (GR-ß-CD) composites using a simple electrochemical methodology, where the CuO NPs are electrodeposited on GR-ß-CD composite modified electrodes. A stable GR-ß-CD composite was prepared by sonication of GR in ß-CD aqueous solution. As-prepared GR-ß-CD/CuO NPs composites were characterized by the high-resolution scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. Cyclic voltammetry results reveal that the GR-ß-CD/CuO NPs composite modified electrode exhibits an excellent catalytic activity and lower reduction potential towards the electrochemical detection of metronidazole (MTZ) over other modified electrodes including GR, GR-ß-CD, and CuO NPs. Under optimized conditions, amperometry was used for the determination of MTZ using GR-ß-CD/CuO NPs composite modified electrodes. The response of MTZ using the composite electrodes was linear over the range from 0.002 to 210.0 µM. This sensor showed the lowest limit of detection of 0.6 nM and was much lower than the previously reported MTZ sensors. In addition, the sensor is highly sensitive, selective and durable in the presence of a range of potentially interfering electroactive compounds.