Linda Dyorisse NYAMEN

A Study of the structural, optical, and photocatalytic properties of Cu3BiS3 nanoparticles by co-thermal decomposition of precursor complexes

Idriss G. Fando, Olalekan C. Olatunde, Adrien P. Yepseu, Gervais A. Tigwere, Linda D. Nyamen, Damian C. Onwudiwe and 1 more

Inorganic Chemistry Communications

In this study, Cu 3 BiS 3 (CBS) nanoparticles were synthesised by the co-thermal decomposition of Cu(II) and Bi(III) dithiocarbamate complexes at 200 °C using oleylamine (OLA) as both solvent and capping agent. The reaction was carried out at different reaction times (60, 90, and 120 min) to study the influence of synthesis time on the structural and optoelectronic properties of the nanomaterials. Powder X-ray diffraction (XRD) analysis of the ternary nanomaterial confirmed the formation of a single-phase orthorhombic wittichenite structure, with lattice parameters of a = 7.705 Å, b = 10.400 Å, and c = 6.730 Å, indicating high crystallinity and phase purity. Compositional analysis via energy-dispersive X-ray spectroscopy (EDX) corroborated the elemental makeup of Cu, Bi, and S in the synthesised nanoparticles. Optical absorption spectroscopy revealed a progressive blue shift in the absorption edge with decreasing reaction time, corresponding to an increase in band gap energies from 1.50 to 1.80 eV, attributed to size-dependent quantum confinement effects. Morphological study showed the formation of irregular rhombohedral particles with average sizes ranging from 49.86 to 50.04 nm according to transmission electron microscopy (TEM). The scanning electron microscopy (SEM) further revealed a microstructure composed of agglomerated, irregularly shaped spherical particles, enhancing surface area and active site accessibility. The as-synthesised CBS nanoparticles exhibited moderate photocatalytic performance in the degradation of methylene blue under visible light irradiation. The activity is attributed to their tailored band gap, high surface area, and porous morphology, rendering them promising candidates for improvement as photocatalysts in wastewater treatment applications. • Cu₃BiS₃ nanoparticles were synthesised at 200 °C via co-thermal decomposition in oleylamine. • XRD confirmed a single-phase orthorhombic wittichenite with high crystallinity. • Band gaps (1.50–1.80 eV) showed a blue shift with shorter reaction times, suggesting quantum confinement. • TEM showed ∼50 nm rhombohedral particles; SEM revealed agglomerated spheres. • Nanoparticles showed moderate visible-light degradation of methylene blue.

• #chalcogenide semiconductor thin films
• #quantum dots synthesis and properties
• #copper-based nanomaterials and applications
• #photocatalysis

Effects of transition metal (Mn2+, Ni2+, and Co3+) doping on the structural and optical properties of pyrrhotite (Fe1-xS) nanoparticles

Gervais A. Tigwere, Malik Dilshad Khan, Linda D. Nyamen, Neerish Revaprasadu, Peter T. Ndifon

Transition Metal Chemistry

• #chalcogenide semiconductor thin films
• #quantum dots synthesis and properties
• #copper-based nanomaterials and applications
• #organometallic chemistry

The nexuses of micro(nano)plastics at environmental interfaces: Challenges in wastewater treatment and sustainable water management

B.G. Fouda-Mbanga, Bothwell Nyoni, Jabulani I. Mnyango, Calvin Phiri, Shanganyane Percy Hlangothi, Aliemeke Miracle and 8 more

Journal of environmental chemical engineering

Micro(nano)plastics (MNPs) have emerged as persistent and complex pollutants, particularly within aquatic systems, with reported concentrations ranging from 0.1 to 1000 particles/L in freshwater and up to 10,000 particles/m 3 in marine environments. Their small size, diverse sources, and high surface reactivity enable interactions with co-contaminants and facilitate long-range transport, posing significant ecological and human health risks. This review explores the critical nexuses of MNPs at environmental interfaces, emphasizing their occurrence in aquatic systems, removal in wastewater treatment plants (WWTPs), and implications for sustainable water management. Bibliometric analysis was used to elucidate research trends, hotspots, and knowledge gaps. The paper discusses MNP transport, persistence, and ecological impacts, as well as current monitoring and detection techniques, highlighting limitations in quantification at sizes below 1 µ m. Conventional WWTPs typically achieve 20–90 % removal of MPs, depending on treatment stages, while advanced approaches—including membrane filtration, adsorption using biochar, carbon nanotubes, and graphene, as well as photocatalytic and electrochemical methods—demonstrate enhanced efficiencies, often exceeding 95 % removal under lab conditions. Policy frameworks and regulatory responses are examined, emphasizing the need for harmonized international standards. Finally, key research needs are outlined, including the development of standardized analytical methods, life cycle assessments, and integrated treatment strategies. Overall, this work provides a multidisciplinary overview of MNP pollution, guiding future research, technological innovation, and policy toward safer and more sustainable water systems.

• #microplastics and plastic pollution
• #recycling and waste management techniques
• #graphene and nanomaterials applications
• #sewage treatment

Hot injection synthesis of CuS decorated CdS and ZnS nanomaterials from metal thiosemicarbazone complexes as single source precursors: Application in the photocatalytic degradation of methylene blue

Adrien P. Yepseu, Line Edwige Tsakeng Ngoudjou, Gervais A. Tigwere, Linda D. Nyamen, Neerish Revaprasadu, Siphamandla C. Masikane and 3 more

Inorganic Chemistry Communications

• #advanced photocatalysis techniques
• #copper-based nanomaterials and applications
• #nanomaterials for catalytic reactions
• #methylene blue

Hot Injection Synthesis of Cus Decorated CDS and Zns Nanomaterials from Metal Thiosemicarbazone Complexes as Single Source Precursors: Application in the Photocatalytic Degradation of Methylene Blue

Peter T. Ndifon, ADRIEN P. YEPSEU PAMEN, Line Edwige Tsakeng Ngoudjou, Gervais A. Tigwere, Linda D. Nyamen, Walter N. Kun and 4 more

SSRN Electronic Journal

• #nanomaterials for catalytic reactions
• #catalysis and hydrodesulfurization studies
• #chemical synthesis and reactions
• #methylene blue

Thiourea‐Derived Single‐Source Molecular Precursor For Spin‐Coated PbS Thin Films

Kevin I.Y. Ketchemen, Vaidehi Lapalikar, Eduardo Carrillo‐Aravena, Linda D. Nyamen, Peter T. Ndifon, Michael Ruck

ChemistryOpen

Abstract In search of a suitable single‐source precursor for the deposition of nanostructured PbS thin films at moderate temperatures under ambient conditions, we have synthesized the ligand N ‐(thiomorpholine‐4‐carbothioyl)benzamide and its corresponding lead(II) complex. The structures of both compounds were determined by single‐crystal X‐ray diffraction. In the complex, two ligands coordinate to a lead(II) atom in hemi‐directed geometry through S and O atoms. Secondary intermolecular Pb⋅⋅⋅S interactions group the complexes into pairs. As bulk powders, both the ligand and complex show nominal composition and purity as evidenced by elemental analysis, 1 H NMR and IR spectroscopy. Thermal analysis of the lead(II) complex was carried out to understand its thermal decomposition behaviour for establishing a thin film fabrication protocol. Thin films of phase‐pure PbS were fabricated using this new molecular precursor at the comparatively low annealing temperature of 250 °C. The film showed nanoparticles with cuboidal morphology and a blue‐shifted optical absorption.

• #quantum dots synthesis and properties
• #copper-based nanomaterials and applications
• #chalcogenide semiconductor thin films
• #thin film

Copper (II) Heterocyclic Thiosemicarbazone Complexes as Single-Source Precursors for the Preparation of Cu9S5 Nanoparticles: Application in Photocatalytic Degradation of Methylene Blue

Adrien P. Yepseu, Thomas Girardet, Linda D. Nyamen, Solenne Fleutot, Kevin I.Y. Ketchemen, Franck Cleymand and 1 more

Catalysts

In this study, two copper(II) complexes, [Cu(C6H8N3S2)2]Cl2 (1) and [Cu(C7H10N3S2)2]Cl2·H2O (2), were synthesized from 2-(thiophen-2-ylmethylene)hydrazine-1-carbothioamide (L1H) and 2-(1-(thiophen-2-yl)ethylidene)hydrazine-1-carbothioamide (L2H) respectively and characterized using various spectroscopic techniques and elemental analyses. The as-prepared complexes were used as single-source precursors for the synthesis of oleylamine-capped (OLA@CuxSy), hexadecylamine-capped (HDA@CuxSy), and dodecylamine-capped (DDA@CuxSy) copper sulphide nanoparticles (NPs) via the thermolysis method at 190 °C and 230 °C and then characterized using powder X-ray diffraction (p-XRD), UV-visible spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The p-XRD diffraction patterns confirmed the formation of crystalline rhombohedral digenite Cu9S5 with the space group R-3m. The TEM images showed the formation of nanoparticles of various shapes including hexagonal, rectangular, cubic, truncated-triangular, and irregularly shaped Cu9S5 nanomaterials. The SEM results showed aggregates and clusters as well as the presence of pores on the surfaces of nanoparticles synthesized at 190 °C. The UV-visible spectroscopy revealed a general blue shift observed in the absorption band edge of the copper sulphide NPs, as compared to bulk CuxSy, with energy band gaps ranging from 2.52 to 3.00 eV. Energy-dispersive X-ray spectroscopy (EDX) confirmed the elemental composition of the Cu9S5 nanoparticles. The nanoparticles obtained at 190 °C and 230 °C were used as catalysts for the photocatalytic degradation of methylene blue (MB) under UV irradiation. Degradation rates varying from 47.1% to 80.0% were obtained after 90 min of exposure time using only 10 mg of the catalyst, indicating that Cu9S5 nanoparticles have potential in the degradation of organic pollutants (dyes).

• #nanocluster synthesis and applications
• #quantum dots synthesis and properties
• #chalcogenide semiconductor thin films
• #nanoparticle

Molecular precursor route for the phase selective synthesis of α-MnS or metastable γ-MnS nanomaterials for magnetic studies and deposition of thin films by AACVD

Gervais A. Tigwere, Malik Dilshad Khan, Linda D. Nyamen, Ahmed A. Aboud, T. Moyo, Sanele Dlamini and 2 more

Materials Science in Semiconductor Processing

• #quantum dots synthesis and properties
• #chalcogenide semiconductor thin films
• #gold and silver nanoparticles synthesis and applications
• #materials science

Optical and Photocatalytic Properties of CuxS/ZnO Composite Thin Films Deposited by Robotic Spray Pyrolysis Deposition

Adrien P. Yepseu, Luminita Isac, Linda D. Nyamen, Franck Cleymand, Anca Duţă, Peter T. Ndifon

Journal of Nanomaterials

This article reports on VIS-active composite thin films based on zinc oxide (ZnO) and copper sulfide (CuxS) deposited using robotic spray pyrolysis deposition (SPD) for the study of the optical and photocatalytic properties. The first step involves the SPD deposition of a CuxS layer onto the glass substrate at 300°C. The second step consists of the deposition of a ZnO layer onto the CuxS layer to form glass/CuxS-ZnO composites that were further annealed at 400°C. The development of the composite thin films was confirmed by XRD and EDX analyses. The band gap energy ( <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:msub> <a:mrow> <a:mi>E</a:mi> </a:mrow> <a:mrow> <a:mtext>g</a:mtext> </a:mrow> </a:msub> </a:math> ) of the bare ZnO thin films decreased from 3.15 eV to an activation energy value of 2.8 eV after the deposition of the ZnO thin layer onto the CuxS layer and from 2.8 to 2.08 eV after annealing the CuxS-ZnO composite at 400°C. The UV-VIS irradiation (5.5% of UV, <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mi>G</c:mi> <c:mo>=</c:mo> <c:mn>55</c:mn> <c:mtext> </c:mtext> <c:mtext>W</c:mtext> <c:mo>/</c:mo> <c:msup> <c:mrow> <c:mtext>m</c:mtext> </c:mrow> <c:mrow> <c:mn>2</c:mn> </c:mrow> </c:msup> </c:math> ) of a 10 ppm methylene blue solution was used to investigate the photocatalytic properties of the CuxS-ZnO composites. The annealed CuxS-ZnO thin films at 400°C demonstrates better photocatalytic activity compared to CuxS-ZnO composites deposited at 300°C. The enhanced photocatalytic efficiency of the annealed CuxS-ZnO thin films may be the result of the diode structure and the increased crystallinity that prevent the electron-hole recombination.

• #advanced photocatalysis techniques
• #copper-based nanomaterials and applications
• #zno doping and properties
• #materials science

CCDC 1569168: Experimental Crystal Structure Determination

Kevin I.Y. Ketchemen, Malik Dilshad Khan, Sixberth Mlowe, Matthew P. Akerman, Íñigo J. Vitórica‐Yrezábal, George F. S. Whitehead and 4 more

The Cambridge Structural Database

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

• #crystallization and solubility studies
• #x-ray diffraction in crystallography
• #crystallography
• #crystal structure

CCDC 2021575: Experimental Crystal Structure Determination

Kevin I.Y. Ketchemen, Malik Dilshad Khan, Sixberth Mlowe, Matthew P. Akerman, Íñigo J. Vitórica‐Yrezábal, George F. S. Whitehead and 4 more

The Cambridge Structural Database

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

• #crystallization and solubility studies
• #x-ray diffraction in crystallography
• #crystallography
• #chemistry

Synthesis of (Bi 1−x Sb x ) 2 S 3 solid solutions via thermal decomposition of bismuth and antimony piperidinedithiocarbamates

Walter N. Kun, Paul D. McNaughter, Linda D. Nyamen, Ben F. Spencer, Paul O’Brien, Peter T. Ndifon and 1 more

RSC Advances

A full range of (Bi _1−x Sb _x ) ₂ S ₃ solid solutions from bismuth and antimony piperidine dithiocarbamate complexes is reported.

• #electronic and structural properties of oxides
• #chalcogenide semiconductor thin films
• #metal extraction and bioleaching
• #antimony

Tailoring Shape and Crystallographic Phase of Copper Sulfide Nanostructures Using Novel Thiourea Complexes as Single Source Precursors

Kevin I.Y. Ketchemen, Malik Dilshad Khan, Sixberth Mlowe, Linda D. Nyamen, Peter T. Ndifon, Paul O’Brien and 1 more

Journal of Inorganic and Organometallic Polymers and Materials

• #quantum dots synthesis and properties
• #chalcogenide semiconductor thin films
• #gold and silver nanoparticles synthesis and applications
• #oleylamine

CCDC 1545392: Experimental Crystal Structure Determination

Kevin I.Y. Ketchemen, Sixberth Mlowe, Linda D. Nyamen, Ahmed A. Aboud, Matthew P. Akerman, Peter T. Ndifon and 2 more

The Cambridge Structural Database

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

• #crystallization and solubility studies
• #x-ray diffraction in crystallography
• #crystallography
• #materials science

CdS thin films deposition by AACVD: effect of precursor type, decomposition temperature and solvent

Kevin I.Y. Ketchemen, Sixberth Mlowe, Linda D. Nyamen, Peter T. Ndifon, Neerish Revaprasadu, Paul O’Brien

Journal of Materials Science Materials in Electronics

• #quantum dots synthesis and properties
• #chalcogenide semiconductor thin films
• #copper-based nanomaterials and applications
• #dithiocarbamate

Synthesis and Crystal Structure of N-(2-Pyridylmethyl)-L-Alanine) Isothiocyanate Cobalt(III)

Sally-Judith E. Ntum, Awawou G. Paboudam, Asseng M. Conde, Linda D. Nyamen, Aminou Mohamadou, James Raftery and 1 more

Crystal Structure Theory and Applications

The title compound, [N-(2-pyridylmethyl)-(L)-alanine]Co(III) thiocyanate (1) was obtained from the reaction of Co(OOCH3)2·H2O with the tridentate reduced Schiff base ligand, N-(2-pyridylmethyl)-(L)-alanine (L) and NH4SCN and characterized by elemental analysis, IR, UV-visible, TGA and single- crystal X-ray diffraction. Structural and spectroscopic analyses reveal [Co(L)2)]SCN to be monomeric with Cobalt(III) adopting a pseudo-octahedral geometry, coordinating to two reduce Schiff base ligands. In the crystal lattice, the thiocyanate anion forms an intermolecular SCN···HNamine hydrogen bond, while adjacent monomers are linked by intermolecular Ocarboxyl···HNamine···H-bonds to form a supramolecular network. This work is therefore undertaken in an attempt to construct coordination framework structures of varying properties using the mixed-ligand strategy involving reduced Schiff bases and the thiocyanate ion.

• #metal-organic frameworks: synthesis and applications
• #crystal structures of chemical compounds
• #metal complexes synthesis and properties
• #thiocyanate

CCDC 1405782: Experimental Crystal Structure Determination

Walter N. Kun, Mlowe, Sixberth, Linda D. Nyamen, Ndifon, Peter T., Malik, Mohammad A., Orde Q. Munro and 1 more

The Cambridge Structural Database

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

• #crystallization and solubility studies
• #x-ray diffraction in crystallography
• #computer science

Heterocyclic Bismuth(III) Dithiocarbamato Complexes as Single‐Source Precursors for the Synthesis of Anisotropic Bi 2 S 3 Nanoparticles

Walter N. Kun, Sixberth Mlowe, Linda D. Nyamen, Peter T. Ndifon, Mohammad Azad Malik, Orde Q. Munro and 1 more

Chemistry - A European Journal

New complexes catena-(μ2 -nitrato-O,O')bis(piperidinedithiocarbamato)bismuth(III) (1) and tetrakis(μ-nitrato)tetrakis[bis(tetrahydroquinolinedithiocarbamato)bismuth(III)] (2) were synthesised and characterised by elemental analysis, FTIR spectroscopy and thermogravimetric analysis. The single-crystal X-ray structures of 1 and 2 were determined. The coordination numbers of the Bi(III) ion are 8 for 1 and ≥6 for 2 when the experimental electron density for the nominal 6s(2) lone pair of electrons is included. Both complexes were used as single-source precursors for the synthesis of dodecylamine-, hexadecylamine-, oleylamine and tri-n-octylphosphine oxide-capped Bi2 S3 nanoparticles at different temperatures. UV/Vis spectra showed a blueshift in the absorbance band edge characteristic of a quantum size effect. High-quality, crystalline, long and short Bi2 S3 nanorods were obtained depending on the thermolysis temperature, which was varied from 190 to 270 °C. A general trend of increasing particle breadth with increasing reaction temperature and increasing length of the carbon chain of the amine (capping agent) was observed. Powder XRD patterns revealed the orthorhombic crystal structure of Bi2 S3 .

• #organometallic compounds synthesis and characterization
• #chalcogenide semiconductor thin films
• #chemical thermodynamics and molecular structure
• #oleylamine

Aerosol assisted chemical vapor deposition (AACVD) of CdS thin films from heterocyclic cadmium(II) complexes

Sixberth Mlowe, Linda D. Nyamen, Peter T. Ndifon, M. A. Malik, James Raftery, Paul O’Brien and 1 more

Inorganica Chimica Acta

• #quantum dots synthesis and properties
• #chalcogenide semiconductor thin films
• #semiconductor materials and interfaces
• #chemistry

CCDC 1008839: Experimental Crystal Structure Determination

Sixberth Mlowe, Linda D. Nyamen, Peter T. Ndifon, M. A. Malik, James Raftery, Paul O’Brien and 1 more

The Cambridge Structural Database

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

• #crystallization and solubility studies
• #x-ray diffraction in crystallography
• #crystal structure
• #crystallography

Low temperature synthesis of PbS and CdS nanoparticles in olive oil

Linda D. Nyamen, Neerish Revaprasadu, Peter T. Ndifon

Materials Science in Semiconductor Processing

• #chalcogenide semiconductor thin films
• #quantum dots synthesis and properties
• #gold and silver nanoparticles synthesis and applications
• #dithiocarbamate

Synthesis of multi-podal CdS nanostructures using heterocyclic dithiocarbamato complexes as precursors

Linda D. Nyamen, Neerish Revaprasadu, Viswanadha Srirama Rajasekhar Pullabhotla, Adeola A. Nejo, Peter T. Ndifon, Mohammad Azad Malik and 1 more

Polyhedron

• #quantum dots synthesis and properties
• #chalcogenide semiconductor thin films
• #nanocluster synthesis and applications
• #oleylamine

The syntheses and structures of Zn(II) heterocyclic piperidine and tetrahydroquinoline dithiocarbamates and their use as single source precursors for ZnS nanoparticles

Linda D. Nyamen, Adeola A. Nejo, Viswanadha Srirama Rajasekhar Pullabhotla, Peter T. Ndifon, Mohammad Azad Malik, Javeed Akhtar and 2 more

Polyhedron

• #quantum dots synthesis and properties
• #chalcogenide semiconductor thin films
• #nanocluster synthesis and applications
• #high-resolution transmission electron microscopy

Synthesis of anisotropic PbS nanoparticles using heterocyclic dithiocarbamate complexes

Linda D. Nyamen, Viswanadha Srirama Rajasekhar Pullabhotla, Adeola A. Nejo, Peter T. Ndifon, Jamie H. Warner, Neerish Revaprasadu

Dalton Transactions

We report the synthesis of lead piperidine and lead tetrahydroquinoline dithiocarbamate (DTC) complexes and their use as single source precursors for the preparation of anisotropic PbS nanoparticles. The complexes were thermolysed in coordinating solvents such hexadecylamime (HDA), tri-n-octylphosphine oxide (TOPO), oleylamine (OA) and decylamine (DA) at various reaction temperatures. The variation of the reaction conditions and precursors produced PbS particles with shapes ranging from spheres to cubes and rods. The size of the particles is generally larger than those synthesized by conventional precursor routes. The electron microscopy and X-ray diffraction data confirm the particles to be very crystalline with the dominant cubic rock salt phase present in all samples.

• #quantum dots synthesis and properties
• #chalcogenide semiconductor thin films
• #nanocluster synthesis and applications
• #oleylamine

Heterocyclic dithiocarbamates: precursors for shape controlled growth of CdS nanoparticles

Linda D. Nyamen, Viswanadha Srirama Rajasekhar Pullabhotla, Adeola A. Nejo, Peter T. Ndifon, Neerish Revaprasadu

New Journal of Chemistry

We report the synthesis of hexadecylamine (HDA) and tri-n-octylphosphine oxide (TOPO) capped CdS nanoparticles using cadmium piperidine dithiocarbamate (DTC) and cadmium tetrahydroquinoline dithiocarbamate complexes as single source precursors. These complexes are easy to prepare, air stable for long periods and pyrolyze to give high quality nanoparticles. The nanoparticles obtained showed quantum confinement with near band edge luminescence. The reaction conditions such as the amount of capping group and reaction temperature were varied to study their influence on the properties and morphology of the nanoparticles. Elongated CdS particles in the form of rods, bipods and tripods were obtained for the HDA capped CdS whereas spherical particles were observed when TOPO was used as the capping material. The X-ray diffraction studies revealed the hexagonal phase to be dominant. Details on the particle crystallinity, size and size distribution were investigated by transmission electron microscopy (TEM) and high resolution TEM.

• #quantum dots synthesis and properties
• #chalcogenide semiconductor thin films
• #nanocluster synthesis and applications
• #dithiocarbamate