Metallic State Research Articles

Spin Manipulation of Co sites in Co9S8/Nb2CTx Mott-Schottky Heterojunction for Boosting the Electrocatalytic Nitrogen Reduction Reaction.

Regulating the adsorption of an intermediate on an electrocatalyst by manipulating the electron spin state of the transition metal is of great significance for promoting the activation of inert nitrogen molecules (N2) during the electrocatalytic nitrogen reduction reaction (eNRR). However, achieving this remains challenging. Herein, a novel 2D/2D Mott-Schottky heterojunction, Co9S8/Nb2CTx-P, is developed as an eNRR catalyst. This is achieved through the in situ growth of cobalt sulfide (Co9S8) nanosheets over a Nb2CTx MXene using a solution plasma modification method. Transformation of the Co spin state from low (t2g 6eg 1) to high (t2g 5eg 2) is achieved by adjusting the interface electronic structure and sulfur vacancy of Co9S8/Nb2CTx-P. The adsorption ability of N2 is optimized through high spin Co(II) with more unpaired electrons, significantly accelerating the *N2→*NNH kinetic process. The Co9S8/Nb2CTx-P exhibits a high NH3 yield of 62.62µg h-1 mgcat. -1 and a Faradaic efficiency (FE) of 30.33% at -0.40V versus the reversible hydrogen electrode (RHE) in 0.1m HCl. Additionally, it achieves an NH3 yield of 41.47µg h-1 mgcat. -1 and FE of 23.19% at -0.60V versus RHE in 0.1m Na2SO4. This work demonstrates a promising strategy for constructing heterojunction electrocatalysts for efficient eNRR.

Effect of hydrogen on oxidative dissolution of epsilon particles-doped UO2 pellets under carbonate condition with hydrogen peroxide

The epsilon particles that result from nuclear fission of UO2 fuel possess both advantages and disadvantages from a spent nuclear fuel (SNF) management perspective. In this study, the effect of epsilon particles, namely Ru, Mo, and Pd, inherent in simulated UO2 pellets is examined. Various analytical methods have been used to explore the changes in the structural, surface, and electrochemical properties of which contain epsilon particles. A notable finding is that the epsilon particles are not evenly distributed and tend to clump together, transforming into a metallic state after sintering, as detailed in the X-ray diffraction analyses. Energy-dispersive X-ray spectroscopy analyses highlight interesting aspects of the distribution of elements, especially the disappearance of Pd during sintering, which is likely due to its high vapor pressure. Although the lattice structure of UO2 remains unchanged, the sizes of the grains and pores visibly change, which may influence the tendency of UO2 pellet-cracking. Despite the addition of the epsilon particles, the electrical conductivity analyses show no significant changes, suggesting that they act as minor impurities without affecting the structural lattice. However, their possible role as catalysts in electrochemical reactions opens new and interesting areas that require thorough investigation. Moreover, examining the anodic dissolution under various conditions provides detailed insights into UO2 dissolution and oxidation, revealing how epsilon particles subtly influence the oxidative dissolution process. This study clarifies the basic interactions and effects of epsilon particles in UO2 pellets and broadens the path for a deeper understanding and improvement of nuclear fuel matrices and steering advancements in the safe and effective use of nuclear energy.

High-performance long-wavelength infrared switchable stealth based on In3SbTe2 metasurface

Metasurface based on phase change material (PCM) for switchable thermal radiation is of great significance to the application of infrared (IR) stealth and thermal management in multi-scenario. However, the previously reported results based on GST and VO2 metasurface face the challenges of relatively low intrinsic loss in metallic state and weak stability, respectively. In this paper, we have designed a plasmonic metasurface thermal emitter (PMTE) based on the PCM of In3SbTe2 (IST), which can manage the thermal emissivity in the wavelength range of 5–14 μm as the IST changes from the amorphous to the crystalline state. For IST in the amorphous state, the PMTE's average emissivity in the wavelength ranges of 5–8 μm and 8–14 μm, are 0.22 and 0.44 respectively, which can be used for the long-wavelength IR (LWIR) stealth of object with low temperature in high-temperature environment. For IST in the crystalline state, the PMTE's average emissivity in the wavelength ranges of 5–8 μm and 8–14 μm, are 0.68 and 0.14 respectively, which can achieve radiative heat dissipation and LWIR stealth of object with high temperature in low-temperature environment. We displayed simulated infrared images of the PMTE in amorphous and crystalline states to demonstrate its switchable LWIR stealth at different temperatures. In addition, the radiative heat dissipation properties of the PMTE are discussed. Our proposed PMTE based on IST can be potentially applied to IR stealth and thermal management in different scenarios.

Switchable terahertz polarization converter with dual-functional reflective conversion and asymmetric transmission based on vanadium dioxide

A dual-functional polarization converter designed for both reflective polarization conversion and asymmetric transmission in the terahertz band is proposed, leveraging the phase transition of vanadium dioxide. In its metallic state, vanadium dioxide facilitates reflective mode operation. Simulation results demonstrate that the polarization conversion rate exceeds 90%, converting linearly polarized or circularly polarized waves into cross-polarized waves, with relative bandwidths of 100.6% and 100.8%, respectively. Experimental validation confirms the polarization conversion capabilities of the device. In the insulating state of vanadium dioxide, the converter demonstrates a notable asymmetric transmission effect for wide-angle incident circularly polarized waves. The proposal of this converter fills the gap of switchable polarization conversion and asymmetric transmission functions, and has broad application prospects in multifunctional polarization devices and multi-channel polarization detection.

Versatile tunable metastructure based on liquid crystal-VO2 for polarization conversion and refractive index sensing

This paper presents a metastructure device (MSD) modulated by liquid crystal (LC) and vanadium dioxide (VO2), suitable for circular-to-linear polarization conversion and refractive index (RI) sensing. The MSD employs a 2 × 2 array as a unit cell, forming a circular-to-linear polarization conversion. Filling the MSD with analytes of different RIs can cause changes in the electromagnetic properties of the MSD, thus realizing the sensing function. Furthermore, the detection range of the sensing can be modified by changing the long-axis pointing of the LC molecules under an applied voltage, resulting in multi-range detection. The RI unit is denoted as RIU. Without an applied voltage, the RI detection range is 1.949–2.607, with a sensitivity of 199 GHz/RIU; under full-bias conditions, the detection range is 2.828–3.391, with a sensitivity of 143 GHz/RIU. In the initial state of LCs, this paper also explores the use of the phase transition of VO2 to adjust the conductivity of VO2 to achieve changes in the detection range. In the insulating state, the detection range is 2.12–2.607, with a sensitivity of 225 GHz/RIU, while in the metallic state, the detection range is 1–2, with a sensitivity of 183 GHz/RIU. Furthermore, altering the thickness of the analyte also affects the electromagnetic properties of the device, causing a shift in the peak axial ratio frequency, making the MSD suitable for analyte thickness detection. The MSD has a wide detection range, high sensitivity, and adaptability, making it suitable for identifying cancer cells and giving a new method of monitoring human health.

Narrow gap semiconductor to metal transition in GdNiSb under pressure

The electronic structure of the GdNiSb compound under pressure has been investigated in the course of first-principles calculations accounting for spin-orbit coupling. At ambient conditions this compound is found to be a narrow gap semiconductor with an indirect band gap of 0.38 eV. Decreasing in the cell volume leads to a gradual redistribution of the density of states caused by band broadening and partial delocalization of the electronic states, in particular the 3d Ni states are strongly modified. The band gap is closed when the volume of the lattice decreases by 35 % or more with a slight metallization at the Fermi energy with the appearance of the Fermi surfaces. For the smaller volumes, the metallic states with non-trivial topological features are calculated for GdNiSb.

Hazard and Health Risk Assessment of Heavy Metals in Non-Alcoholic Beverage Consumed in Abia State, Nigeria

The quality of non-alcoholic beverages consumed in Aba, Abia State, southeastern Nigeria and health risk assessment of heavy metals required periodic evaluation so as to avert potential health hazard. Hence, the objective of this paper as to evaluate the hazard and health risk assessment of heavy metals in non-alcoholic beverages consumed in Abia State, Nigeria using health risk assessment models. Heavy metals concentrations were determined using atomic absorption spectrophotometer (Agilent 280FS AA). The average heavy metal concentrations of non-alcoholic drink samples ranged from 0.040 - 1.132 mg/l in ascending order of Zn < Cd < Co < Cu < Pb <Cr < Mn < Fe respectively. The average concentrations of Mn, Cr, Cd, Fe and Pb exceeded the standard maximum permissible limits for drinking water quality. The values of estimated daily intake for Cd, Fe, Pb, Cr, Mn and Zn were within acceptable provisional tolerable daily intake and safe limits. The hazard quotient (HQ) values for Mn, Cr, Cd, Zn and Fe were within safe limit (< 1.0), except for Co and Pb that had HQ values greater than one in over 37.5 % of the total samples, indicating associated potential chronic health risks. Hazard index of 72.5% of all the non-alcoholic drink samples were above the safe limit (>1.0), signifying potential chronic health risk as a result of combine effects of these heavy metals. The incremental life cancer for Cr, Cd and Pb ranged from 2.59E-05 - 1.79E-03, 1.35E-04 – 2.81E-04 and 3.92E-06 - 3.24E-05 respectively. The incremental life cancer values of Pb were within the recommended safe limit of not greater than 1.0 × 10-4 and has the least likelihood of any potential cancer risks. However, Cd, and Cr had cancer risk values higher than the save limits, indicating potential life cancer health risks in both children and adult population.

Detectable Adhesives: Nondestructive Detection of Adhesion

AbstractMetal‐to‐metal adhesives are vital across diverse sectors including automotive, aerospace, and industrial assembly. However, traditional adhesion detection methods are mainly based on the fracture mechanism, posing challenges for nondestructive detection. Here, a nondestructive method that leverages electrical signals to monitor the adhesion state of metal interfaces in real‐time is presented. The approach utilizes detectable adhesives (DA) synthesized from poly(ionic liquid) (PIL), which not only exhibit robust adhesion properties (4.9 MPa) but also function as ionic conductors. By correlating changes in capacitance and resistance with the adhesive state, the method allows for in situ monitoring of the curing process, prediction of adhesion strength, and early detection of potential failures. This dual‐sensing capability, combining electrical and mechanical aspects, enhances understanding of adhesive behavior in diverse conditions, presenting a fresh approach for digitally transforming adhesive technologies.

DFT study of electron energy loss spectra of sulfur in Janus MoSSe, MoSTe, WSSe and WSTe monolayers

In this paper, electronic properties of Janus MSX monolayers (M = Mo, W; X = Se or Te), including electron energy loss near edge structures (ELNES), as K and [Formula: see text] edge spectra of sulfur atoms, have been calculated using a full potential scheme and the augmented plane wave plus local orbitals (APW+lo) method in the framework of density functional theory (DFT). Due to the lack of experimental results, the obtained spectra are compared with the corresponding spectra of MoS2 monolayer. The band structure analysis shows that the Janus MoSSe and WSSe monolayers are direct bandgap semiconductors, while the Janus MoSTe and WSTe monolayers are indirect bandgap semiconductors. In comparison to MoS2, the main structures of the K edge ELNES spectra of sulfur atoms in Janus monolayers occur at lower energies, due to the structural change and increased bond length. The relative reduction of intensities in the main structures predicts the possibility of reducing the number of partial densities of states (PDOS), that is, the reduced p PDOS for the K edge in the corresponding energy range. In the K ([Formula: see text] edge ELNES spectra of the sulfur atom in Janus monolayers and MoS2 monolayers, the main structures are due to the electron transfer to the unoccupied [Formula: see text] and [Formula: see text] states (3s of sulfur and 4d states of the transition metal).

Dual-Tuned Terahertz Absorption Device Based on Vanadium Dioxide Phase Transition Properties.

In recent years, absorbers related to metamaterials have been heavily investigated. In particular, VO2 materials have received focused attention, and a large number of researchers have aimed at multilayer structures. This paper presents a new concept of a three-layer simple structure with VO2 as the base, silicon dioxide as the dielectric layer, and graphene as the top layer. When VO2 is in the insulated state, the absorber is in the closed state, Δf = 1.18 THz (absorption greater than 0.9); when VO2 is in the metallic state, the absorber is open, Δf = 4.4 THz (absorption greater than 0.9), with ultra-broadband absorption. As a result of the absorption mode conversion, a phenomenon occurs with this absorber, with total transmission and total reflection occurring at 2.4 THz (A = 99.45% or 0.29%) and 6.5 THz (A = 90% or 0.24%) for different modes. Due to this absorption property, the absorber is able to achieve full-transmission and full-absorption transitions at specific frequencies. The device has great potential for applications in terahertz absorption, terahertz switching, and terahertz modulation.

Polar Metallicity Controlled by Epitaxial Strain Engineering.

The discovery of polar metal opens the door to incorporating electric polarization into electronics with the potential to invigorate next-generation multifunctional electronic devices. Especially, electric polarization can be induced by geometric design in non-polar perovskite oxides. Here, the epitaxial strain exerted on the deposited single-crystalline NdNiO3 thin films is systematically varied in both sign and amplitude by choosing substrates with different lattice mismatch. The pseudocubic NdNiO3(111) film, which is non-polar in its bulk state, is induced to be polar under both compressive and tensile strain. The fine-tuning of epitaxial strain is realized by continuously varying the film thickness using the "thickness-wedge" growth technique, and from the elucidated thickness dependence, the electric polarization and metallicity can be further optimized. Moreover, transitioning from isotropic to anisotropic epitaxial strain gives rise to an ideal polar metal state in the pseudocubic NdNiO3(102) film on an orthorhombic substrate, achieving a remarkably low resistivity of 173 µΩcm at room temperature. The metal-insulator transition in NdNiO3 is completely suppressed and the polar metal state becomes the ground state at all temperatures. These results demonstrate alluring possibilities of induction and manipulation of both electric polarization and electric transport properties in functional perovskite oxides by epitaxial strain engineering.

Modulating the valence states of transition metals in FeCoNiMnW high-entropy alloys for enhanced oxygen evolution reaction activity

Amorphous high-entropy alloys (HEA) are promising electrocatalysts with multi-element active sites and dense defect distribution, high valences of 3d transition metals (3d TMs) are beneficial for the oxygen evolution reaction (OER). However, it is still unknown how to enhance the 3d TMs valence state in amorphous HEA to improve OER catalytic activity. Herein, we successfully boosted the valence state of 3d TMs in HEA through electronegativity. The prepared FeCoNiMnW HEA exhibited significant amorphous characteristics. X-ray photoelectron spectroscopy analysis confirmed the formation of Ni3+ sites after adding electronegative W and the widespread occurrence of oxygen vacancies through amorphization. The enhanced oxidation state of Ni reduced the overpotential, while the abundant oxygen vacancies significantly facilitated electron transfer and thus boosting the rate of catalytic reactions. These characteristics lead to the amorphous FeCoNiMnW HEA exhibiting excellent OER performance. Amorphous FeCoNiMnW HEA films deposited on carbon cloth loaded with carbon nanotubes (FeCoNiMnW@CCC) only require an overpotential of 253 mV to generate a current density of 10 mA cm−2, which is much lower than RuO2 films (399 mV) and commercial RuO2 (309 mV), and shows excellent durability for 700 h at 20 mA cm−2 and 100 h at 200mA cm−2. This work provides a novel strategy for designing high-performance OER catalysts through structural and electronic modulation.

Plasmonic resonance and sensing based on Sb2Te3 topological insulator nanocolumn array

Topological insulators (TIs) are new kind of electronic materials with special energy band structures and topological properties. With topologically-protected metallic surface state and insulating bulk state, TIs have excellent electronic and optical characteristics containing the excitation of surface plasmons. Herein, we deposited the antimony telluride (Sb2Te3) TI layer using the magnetron sputtering method and employed focused ion beam (FIB) lithography to fabricate a nanocolumn array on the Sb2Te3 layer. The experimental measurements show that the localized surface plasmon resonance (LSPR) can be excited in the Sb2Te3 TI nanocolumn array in the visible region. The resonance wavelength is dependent on the size and period of the Sb2Te3 nanocolumn array. The experiment results are in good agreement with the finite-difference time-domain (FDTD) numerical simulations. Moreover, the LSPR enables to realize the microscale optical sensing of the surrounding refractive index with a high sensitivity of 450 nm/RIU. This work will pave a new pathway for the excitation of surface plasmons in TI materials and their applications in optical sensing at the microscale.

Rational design of titanium-doped Y zeolite for hydrodenitrogenation of aromatic N-heterocyclic compounds

Ti modified Y zeolites with different Ti content were synthesized by in-situ hydrothermal crystallization method and used as the support of hydrodenitrogenation (HDN) catalyst. The forms of Ti species in the zeolites and the effect of Ti incorporation on the active metal states of the corresponding catalysts were investigated by XRD, UV–Vis DRS, XPS, HAADF-STEM, ICP-OES, Py-FTIR, H2-TPR, HRTEM, and DFT calculation. The results show that the incorporation of in-situ Ti species into Y zeolite led to a decrease in the Brønsted acid sites (BAS) /Lewis acid sites (LAS) value of the corresponding catalyst, but effectively enhanced the stacking layer number of the WS2 active phase by weakening the interaction between the active metals and the supports, which is manifested in the improvement of the hydrogenolysis activity and the decrease of the hydrogenation activity of the catalyst. When the hydrogenolysis activity and hydrogenation activity in the catalyst match to a certain extent, that is, the BAS/LAS value and the stacking layer number of the active phase reach an appropriate value, the HDN catalyst exhibited the highest catalytic activity. The NiW/Y-0.1Ti catalyst with suitable amount of BAS and stacking layer number of active phase showed the maximum kHDN values (11.7 × 10-4 mol·g−1·h−1 and 3.9 × 10-4 mol·g−1·h−1) and TOFs (1.91 h−1 and 1.04 h−1) of quinoline and indole HDN.

A terahertz broadband and narrowband switchable absorber based on joint modulation of vanadium dioxide and graphene surfaces

Abstract In this paper, a terahertz broadband and narrowband switchable absorber is proposed. The absorption performance tuning for both broadband and narrowband functions is realized based on the joint modulation of vanadium dioxide (VO2) and graphene surfaces. Concretely, while VO2 is in the metallic state, the absorber achieves broadband absorption function. The overall bandwidth of over 90% absorption is 4.04 THz corresponding to a relative bandwidth of 84%. Through regulating the conductivity of VO2, dynamic tuning of the absorption amplitude is obtained and the modulation depth is 96%. By manipulating the graphene Femi energy and VO2 conductivity simultaneously, dynamic tuning of the absorption bandwidth is realized. In particular, the spectral center frequency of broadband absorption remains stable without drifting during the tuning process. While VO2 is in the insulating state, the absorber achieves narrowband absorption function. Calculated results show that two separate perfect absorption peaks are formed, and the absorption amplitudes are 99.6% and 99.2% respectively. Through regulating the Fermi energy of graphene surface, the dynamic tuning of narrowband absorption frequency is realized. Compared with the ones reported in recent years, our absorber has the advantage on function realization, absorption characteristics and performance tuning.

Deep neural network-enabled multifunctional switchable terahertz metamaterial devices

Under the support of deep neural networks (DNN), a multifunctional switchable terahertz metamaterial (THz MMs) device is designed and optimized. This device not only achieves ideal ultra-wideband (UWB) absorption in the THz frequency range but enables dual-functional polarization transformation over UWB. When vanadium dioxide (VO2) is in the metallic state, the device as a UWB absorber with an absorption rate exceeding 90% in the 2.43–10 THz range, with a relative bandwidth (RBW) of 145.2%, and its wideband absorption performance is insensitive to polarization. When VO2 is in the insulating state, the device can switch to a polarization converter, achieving conversions from linear to cross polarization and from linear to circular polarization in the ranges of 4.58–10 THz and 4.16–4.43 THz, respectively. Within the 4.58–10 THz range, the polarization conversion ratio approaches 100% with an RBW of 74.3%, the polarization rotation angle is near 90°. Within the 4.16–4.43 THz range, the RBW is 6.29% and the ellipticity ratio approaches 1, Moreover, the effects of incident angle and polarization angle on the operational characteristics are studied. This THz MMs due to its advantages of wide angle, broad bandwidth, and high efficiency, provides valuable references for the research of new multifunctional THz devices. It has great application potential in short-range wireless THz communication, ultrafast optical switches, high-temperature resistant switches, transient spectroscopy, and optical polarization control devices.

Superconductivity and Metallic Behavior in Heavily Doped Bulk Single Crystal Diamond and Novel Transportation Behavior at Graphene/Diamond Heterostructure

AbstractOwing to extremely large bandgap of 5.5 eV and high thermal conductivity, diamond is recognized as the most important semiconductor. The superconductivity of polycrystalline diamond has always been reported, but there are also many controversies over the existence of superconductivity in bulk single crystal diamond. Besides, it remains a question whether a metallic state exists for such a large bandgap semiconductor. Herein, a single crystal superconducting diamond with a Hall carrier concentration larger than 3 × 1020 cm−3 is realized by co‐doped of boron and nitrogen, with an extremely low resistivity of 2.07 × 10−3 Ω cm at room temperature and dominated acceptor–donor bounded exciton photoluminescence. Furthermore, it is shown that diamond can transform from superconducting to metallic state under similar carrier concentration with tuned carrier mobility degrading from 9.10 cm2 V−1 s−1 or 5.30 cm2 V−1 s−1 to 2.66 cm2 V−1 s−1 or 1.34 cm2 V−1 s−1. Through integrating graphene on a nitrogen and boron heavily co‐doped diamond, a novel transportation behavior in the monolayer graphene similar with superconducting behavior is realized through combining Andreev reflection and exciton‐mediated superconductivity, which may reveal more interesting superconducting behavior of diamond.

Interface-stabilized high-valent Sn enables efficient CO2 electroreduction to formate/formic acid across the full pH range

The electrocatalytic synthesis of formate/formic acid (HCOO−/HCOOH) from CO2 can mitigate environmental issues and provide high-value-added products. Although tin oxide is an excellent catalyst for HCOO−/HCOOH production, it is easily reduced to its metallic state at high potentials, which decreases its activity. Additionally, tin oxide is challenging to stabilize in acidic electrolytes. Here, we introduced Cu to tin oxide catalysts to form Cu6Sn5@SnOx during the CO2 electroreduction process (CO2RR), achieving a high HCOO−/HCOOH Faradaic efficiency (88.4 % at 800 mA cm−2 in 1 M KOH electrolyte, 87.8 % at 300 mA cm−2 in 0.1 M H2SO4 electrolyte containing 1 M K+) and a maximum HCOO− partial current density (757.5 mA cm−2). The in situ spectroscopy and DFT calculations results revealed that the SnOx/Cu6Sn5 alloy interface plays a crucial role in stabilizing the surface high-valent Sn, which provides a thermodynamically stable environment for adsorbed *OCHO intermediate. This discovery offers new insights into the roles of each component in bimetallic catalysts in CO2 reduction.

Achieving broadband multifunctional modulation of wavefront via terahertz anisotropic metasurface

Vanadium dioxide (VO2) has become a reliable phase change material (PCM) and is increasingly utilized in multifunctional metasurface design. This study introduces designs of bilayer anisotropic VO2meta-atoms in simulation for multifunctional wavefront modulation in the terahertz band. By leveraging the phase change property of VO2 and incident wave polarization, a reconfigurable metasurface composing anisotropic meta-atoms is proposed with four distinct functions. When VO2 is in its insulating state, the metasurface serves as a hologram generator for the x-polarized wave and a focusing reflector for the y-polarized wave. Upon the transition of VO2 into the metallic state, the metasurface functions as a generator of vortex beam for the x-polarized wave, while as an anomalous reflector for the y-polarized wave. The proposed metasurface showcases an outstanding broadband performance, delivering impressive four-channel wavefront modulation within a frequency range of 2.2–3.0 THz. Depending on the compact structure and integrated multi-functionalities, our design may have immense potential across a wide range of terahertz applications, including communication exchange and multiplexing utilization.

Investigating Cu-Site Doped Cu-Sb-S Nanoparticles Using Photoelectron and Electron Paramagnetic Resonance Spectroscopy.

Tetrahedrite (Cu12Sb4S13) and famatinite (Cu3SbS4) are good candidates for green energy applications because they possess promising thermoelectric and photovoltaic properties as well as contain earth-abundant and nontoxic constituents. Herein, X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and electron paramagnetic resonance spectroscopy (EPR) methods examined inherent electronic properties and interatomic magnetic interactions of Cu-site doped tetrahedrite and famatinite nanomaterials. An energy-efficient modified polyol method was utilized for the synthesis of tetrahedrite and famatinite nanoparticles doped on the Cu-site with Zn, Fe, Ni, Mn, and Co. This is the first parallel study of tetrahedrite and famatinite nanomaterials with XPS, UPS, and EPR methods alongside a systematic analysis of dopant-dependent effects on the electronic structure and magnetic interactions for each material. XPS showed that the Cu and Sb species in tetrahedrite and famatinite possess different oxidation states, while UPS characterization reveals larger dopant-dependent shifts in the work function for tetrahedrite nanoparticles (4.21 to 4.79 eV) than for famatinite nanoparticles (4.57 to 4.77 eV). Finally, all famatinite nanoparticles display an EPR signal, indicating trace amounts of paramagnetic Cu(II) present below the detection limit of XPS. For tetrahedrite, EPR signatures were observed only for the Zn-doped and Mn-doped nanoparticles, suggesting signal broadening from Cu-Cu spin exchange or spin-lattice relaxation. This study demonstrates the complementary nature of XPS and EPR techniques for studying the oxidation states of metals in solid-state nanomaterials. Comparing the electronic and magnetic properties of tetrahedrite and famatinite while studying the impact of dopant incorporation will guide future endeavors in designing sustainable, high-performance materials for renewable energy applications.