mJ Mol Research Articles

Unveiling the Mechanism of Plasma-Catalytic Low-Temperature Water-Gas Shift Reaction over Cu/γ-Al2O3 Catalysts.

The water-gas shift (WGS) reaction is a crucial process for hydrogen production. Unfortunately, achieving high reaction rates and yields for the WGS reaction at low temperatures remains a challenge due to kinetic limitations. Here, nonthermal plasma coupled to Cu/γ-Al2O3 catalysts was employed to enable the WGS reaction at considerably lower temperatures (up to 140 °C). For comparison, thermal-catalytic WGS reactions using the same catalysts were conducted at 140-300 °C. The best performance (72.1% CO conversion and 67.4% H2 yield) was achieved using an 8 wt % Cu/γ-Al2O3 catalyst in plasma catalysis at ∼140 °C, with 8.74 MJ mol-1 energy consumption and 8.5% H2 fuel production efficiency. Notably, conventional thermal catalysis proved to be ineffective at such low temperatures. Density functional theory calculations, coupled with in situ diffuse reflectance infrared Fourier transform spectroscopy, revealed that the plasma-generated OH radicals significantly enhanced the WGS reaction by influencing both the redox and carboxyl reaction pathways.

FePd2Te2: An Anisotropic Two-Dimensional Ferromagnet with One-Dimensional Fe Chains.

Two-dimensional (2D) magnets have attracted significant attention in recent years due to their importance in the research on both fundamental physics and spintronic applications. Here, we report the discovery of a new ternary compound FePd2Te2. It features a layered quasi-2D crystal structure with 1D Fe zigzag chains extending along the b-axis in the cleavage plane. Single crystals of FePd2Te2 with centimeter size could be grown. Density functional theory calculations, mechanical exfoliation, and atomic force microscopy on these crystals reveal that they are 2D materials that can be thinned down to ∼5 nm. Magnetic characterization shows that FePd2Te2 is an easy-plane ferromagnet with TC ∼ 183 K and strong in-plane uniaxial magnetic anisotropy. Magnetoresistance and the anomalous Hall effect demonstrate that ferromagnetism could be maintained in FePd2Te2 flakes with large coercivity. A crystal twinning effect is observed by scanning tunneling microscopy which makes the Fe chains right angle bent in the cleavage plane and creates an intriguing spin texture. Besides, a large electronic specific heat coefficient of up to γ ∼ 32.4 mJ mol-1 K-2 suggests FePd2Te2 is a strongly correlated metal. Our results show that FePd2Te2 is a correlated anisotropic 2D magnet that may attract multidisciplinary research interests.

A comparative study of magnetic behaviours in bulk and ribbon samples of PrMn2Ge2 compound

The magnetic properties of PrMn2Ge2 samples in both the as-cast bulk and melt-spun ribbon forms have been investigated in detail by a comprehensive set of x-ray and neutron powder diffraction, magnetic and heat capacity measurements and corresponding sets of data analyses. Thermal expansion measurements indicate the presence of magnetoelastic coupling effects around all transition temperatures in the bulk sample. The bulk modulus K0 = 42.0 GPa and its first derivative K0’ = 18.7 have been derived from the pressure-volume data. The Curie temperature from the intralayer antiferromagnetism (AFl) of PrMn2Ge2 to a canted spin structure (Fmc) is TCinter = 332 K for the bulk sample, decreasing to TCinter = 320 K for the ribbon sample. The critical components γ, β and δ of this second order magnetic transition as determined from Kouvel-Fisher analyses, indicate long range magnetic interactions around TCinter. Based on these critical exponents the magnetization, field and temperature data around TCinter collapse onto two curves obeying the single scaling equation M(H,ε)=εβf±(Hεβ+γ). The Debye temperatures and the density of states at the Fermi level are θD=306K and N(EF)=3.47state/eVatom for the bulk sample and θD=320K and (EF)=2.18state/eVatom for the ribbon sample with the nuclear specific heat coefficient for bulk PrMn2Ge2 derived from the splitting of the nuclear hyperfine levels as CN = 517 mJ mol−1 K−1. With a field change of ΔB = 5 T, the maximum values of the magnetic entropy changes -ΔSmax in the region around TCinter are -ΔSmax = 3.00 J/kg K and 2.35 J/kg K for the bulk and ribbon samples respectively, while the relative cooling power (RCP) for the ribbon-spun sample, RCP = 135.9 J/kg, is significantly higher than the value of RCP = 116.6 J/kg for the bulk sample. These findings indicate that PrMn2Ge2 could be a promising candidate for magnetic refrigeration applications in the room temperature region.

Single crystal synthesis and physical property of Ba8Cu1·0Ni2.5Ga10Si33.5 clathrate

This study reports the synthesis of type-I Ba8CuNi2.5Ga10Si33.5 clathrate as a single crystal by the flux method and physical properties investigations such as structural, chemical, magnetic, and thermal properties. Structural refinements indicate Ba atoms are situated at 2a and 6d positions with mixed occupancy across framework sites. Raman spectroscopy assessed host-guest interactions, while the compound's morphology and composition were investigated by the scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) analyses. Magnetic properties revealed ferromagnetic interactions characterized by a positive Weiss constant and weak ferromagnetic hysteresis. The compound's metallic nature is evidenced by increased resistivity with temperature. The Sommerfeld coefficient, estimated at 12.59 mJ mol−1 K−2 from heat capacity data, alongside a pronounced peak around 15 K in the Cp/T3 vs T plot, suggests an Einstein contribution in heat capacity.

Discovery and Characterization of Antiferromagnetic UFe5As3.

This work presents a study on a new uranium iron arsenide UFe5As3. By implementing Bi-flux synthesis, we were able to grow mm-sized single crystals of this compound, which show twinning. UFe5As3 is one of only two known uranium iron arsenides. It adopts a monoclinic, UCr5P3-type crystal structure (space group P21/m, Pearson symbol mP18, a = 7.050(2) Å, b = 3.8582(9) Å, c = 9.634(1) Å, β = 100.25(1)°). The magnetic susceptibility of UFe5As3 indicates it to be an antiferromagnet with TN = 47 K and μeff = 4.94 μB per formula unit, signaling that both U and Fe are likely magnetic in this material. The material appears to be anisotropic, with a small (likely ferromagnetic) spin reorientation transition around T = 29 K. The Sommerfeld coefficient γ0 = 135 mJ mol-1 K-2 suggests enhanced effective electron mass in UFe5As3, while electrical resistivity indicates metallic, Kondo-like behavior.

Plasma nitrogen fixation system with dual-loop enhancement for improved energy efficiency and its efficacy for lettuce cultivation

Plasma nitrogen fixation (PNF) has been emerging as a promising technology for greenhouse gas-free and renewable energy-based agriculture. Yet, most PNF studies seldom address practical application-specific issues. In this work, we present the development of a compact and automatic PNF system for on-site agricultural applications. The system utilized a gliding-arc discharge as the plasma source and employed a dual-loop design to generate from air and water under atmospheric conditions. Experimental results showed that the system with a dual-loop design performs well in terms of energy costs and production rates. Optimal operational parameters for the system were determined through experimentation, resulting in an energy cost of 13.9 MJ mol−1 and an energy efficiency of 16 g kWh−1 for production, respectively. Moreover, the concentration of exhausted NO x was below the emission standards. Soilless lettuce cultivation experiments demonstrated that produced by the PNF system could serve as liquid nitrate nitrogen fertilizer. Overall, our work demonstrates the potential of the developed PNF system for on-site application in the production of green-leaf vegetables.

Research on key influencing factors and mechanisms of improved nitrogen fixation efficiency in magnetic-driven gliding arc

Gliding arc is considered to be an efficient method for nitrogen fixation. In this study, an improved magnetic-driven rotating gliding arc method was adopted to investigate the effects of gas flow rate, current, magnetic field, nitrogen-to-oxygen ratio in the working gas, and relative humidity on nitrogen fixation efficiency. To further understand the relationship between the discharge mechanism and nitrogen fixation efficiency, the arc length, arc diameter, arc rotation frequency, and reaction pathway were studied to find the relationship between external parameters, discharge characteristics, and nitrogen fixation efficiency. The research results indicate that the discharge current and magnetic field not only change the rotation frequency of the gliding arc, but also affect its length and diameter, and the amount of ionizing gases involved in the working gas, thus affecting nitrogen fixation efficiency. When the nitrogen volume ratio in the feed gas is 60%, the lowest energy cost can be achieved, which is 18.6% lower than that of air. The energy cost of nitrogen fixation is closely related to the humidity of the air. As the humidity increases, the energy cost also increases. At the magnetic field strength of 160 mT, gas flow rate of 10 l min−1, and current of 40 mA, the energy cost of 1.708 MJ mol−1 is realized which is the current lowest for plasma nitrogen fixation in this study.

Enhanced magnetocaloric effect accompanying successive magnetic transitions in TbMn2Si2-xGex compounds

The lack of magnetic refrigeration (MR) materials with high magnetocaloric effect (MCE) and large relative cooling power (RCP) in the temperature range required for hydrogen liquefaction (20 K–77 K) is a bottleneck for practical applications of MR cooling systems. The present investigation of TbMn2Si2-xGex compounds (x = 0.1, 0.2) by variable temperature neutron and synchrotron X-ray diffraction, magnetization and heat capacity measurements, establish that substitution of Si with Ge in TbMn2Si2 leads to a significant enlargement of the unit cell and modification of the magnetic properties. Two consecutive ferromagnetic first-order transitions occur below 77 K with the third transition from paramagnetism to a collinear antiferromagnetic state being determined around 500 K. The resultant plateau-like MCE with large RCP below 77 K in these designed compounds offers scope for application for hydrogen liquefaction. Detailed neutron investigation confirm that four magnetic states exist within the temperature range 5 K to 500 K, with two successive first-order magnetic transitions below 77 K responsible for the large MCE. Our specific heat studies provide evidence of strong contributions from the nuclear specific heat and the corresponding nuclear specific heat coefficients of A = 430 ± 50 mJ mol−1 K and A = 418 ± 60 mJ mol−1 K have been determined for TbMn2Si2-xGex with x = 0.1 and x = 0.2, respectively. The overlapping entropy curves near these successive transitions lead to a plateau-like magnetothermal effect as well as a large reversible MCE for both samples (e.g. ΔSMmax = 14.0 J/kg K and ΔTmax = 7.6 K; RCP = 379 J/kg for TbMn2Si1.9Ge0.1 for an applied field of 5 T) indicating that the material can operate over a wide temperature range – particularly for hydrogen liquefaction.

Efficient N2 fixation in air enabled by mechanical-energy-driven triboelectric plasma jet

N2 fixation driven by mechanical energy is a promising strategy for production of nitrogen-enriched compounds. However, the activity of mechanical-energy-driven N2 fixation is very low. Herein, a mechanical-energy-driven triboelectric plasma jet was constructed to achieve N2 fixation in air at room temperature and atmospheric pressure. Under optimal conditions, the NOX production rate of 4.82 μmol h−1 is 23-fold better than the previous record using a triboelectric nanogenerator. The electrical to chemical energy conversion efficiency and energy cost for NOX production are 4.92% and 1.76 MJ mol−1 N−1, respectively, and the energy cost is the best result in the reported plasma N2 fixation reaction at room temperature and atmospheric pressure. Because of the lower average energy of electrons in the triboelectric plasma jet, the vibrational excitation dissociation process with low energy barriers is the major mechanism for N2 fixation. This study provides an effective strategy for N2 fixation using mechanical energy.

Realization of Z2 Topological Metal in Single‐Crystalline Nickel Deficient NiV2Se4

AbstractTemperature‐dependent electronic and magnetic properties are reported for nickel‐deficient NiV2Se4. Single‐crystal X‐ray diffraction shows it to crystallize in the monoclinic Cr3S4 structure type with space group and vacancies on the Ni site, resulting in the composition Ni0.85V2Se4 in agreement with our electron‐probe microanalysis. Structural distortions are not observed down to 1.5 K. Nevertheless, the electrical resistivity shows metallic behavior with a broad anomaly around 150–200 K that is also observed in the heat capacity data. This anomaly indicates a change of state of the material below 150 K. It is believed that this anomaly could be due to spin fluctuations or charge‐density‐wave fluctuations, where the lack of long‐range order is caused by vacancies at the Ni site of Ni0.85V2Se4. The non‐linear temperature dependence of the resistivity as well as an enhanced value of the Sommerfeld coefficient mJ mol−1 K−2 suggest strong electron–electron correlations in this material. First‐principles calculations performed for NiV2Se4, which are also applicable to Ni0.85V2Se4, classify this material as a topological metal with and coexisting electron and hole pockets at the Fermi level. The phonon spectrum lacks any soft phonon mode, consistent with the absence of periodic lattice distortion in the present experiments.

Prevailing surface reactions in the plasma-catalytic ammonia synthesis with Ru/CeO2 and Ru/Ti-CeO2

Sustainable plasma-catalytic NH3 synthesis is receiving an increasing amount of interest as a greener alternative for the conventional Haber-Bosch (HB) process. However, the best energy efficiency for the plasma synthesis reported so far is still low compared to the one of HB. This research was conducted to experimentally investigate one of the plasma process rate-limiting steps, which is N2 bond breaking. This study aimed at identifying the enhancing-surface reactions as well as limiting surface reactions such as H-inhibition. Ru/CeO2 and Ru/Ti-CeO2 were tested in a packed-bed DBD reactor to investigate the influence of TiO2 addition, which possibly prevented H-inhibition, and simultaneously enhanced different surface reactions. Variations of feed gas ratios and designed operation schemes were studied to elucidate the effect of the catalyst composition. Results showed that Ru/Ti-CeO2 outperformed Ru/CeO2 in terms of energy consumption and a N2-rich atmosphere was needed to obtain minima of 84.5 MJ mol−1 and 126.5 MJ mol−1, respectively. The addition of TiO2 in the catalysts provided more surface sites for H2 to adsorb on, which was identified as main reason for improving the energy efficiency of the plasma-catalytic NH3 synthesis.Three detailed reaction mechanisms were proposed to elaborate on the behavior between N2-rich plasma and Ru/Ti-CeO2.

Synthesis, structural and physical properties of new ternary metal-rich phosphides M3Ge2P (M = Mo and W)

We report on the successful synthesis of two new ternary metal-rich phosphides Mo3Ge2P and W3Ge2P, and on their structural, electrical, magnetic, thermal and electronic properties. Mo3Ge2P is thermally stable below 1500 ​°C, while W3Ge2P decomposes initially at 1110 ​°C and finally evolves into W, Ge, and P above 1360 ​°C. They adopt a non-centrosymmetric orthorhombic structure with space group C2v16—Ama2 (No. 40). In the unit cell with content Z ​= ​4, Mo (W) atoms are located at two inequivalent sites, respectively 4b (Mo1/W1) and 8c (Mo2/W2) Wyckoff positions, Ge and P atoms occupy 8c and 4b positions, respectively. The structure is made up of networks organized by edge-shared (Mo1/W1)3P3 planar six-membered rings and edge-shared (Mo2/W2)3Ge3 chair-form six-membered rings. Both compounds exhibit weak magnetism and metallic conduction with electron-dominant charge carriers at high temperatures, as revealed by magnetic susceptibility, electrical resistivity and Seebeck effect. Sommerfeld coefficient γ and Sommerfeld-Wilson ratio Rw were derived as 8.87 ​mJ ​mol−1 ​K−2, 1.69 for Mo3Ge2P and 9.85 ​mJ ​mol−1 ​K−2, 1.78 for W3Ge2P, indicating weak electron-electron correlation in the system. Analyses on thermal conductivity (κ) suggest a considerable phonon contribution κL to the total one in these metallic materials. First-principles calculations demonstrate that the Mo-4d (W-5d) orbital electrons dominate the band structures and density of states near the Fermi level.

MgPdSb─An Electron-Deficient Half-Heusler Phase

The half-Heusler family consists of many semiconducting intermetallic compounds, virtually all of them having a valence electron count (VEC) of 18. We have studied an electron-deficient (VEC = 17) phase MgPdSb and its Pd-stuffed variant MgPd1.25Sb. The cubic F4̅3m crystal structure was confirmed by the Rietveld refinement of powder X-ray diffraction (XRD) data. The lattice parameter is a = 6.284 and 6.335 Å for MgPdSb and MgPd1.25Sb, respectively. The Debye temperature and Sommerfeld coefficient for MgPdSb are ΘD = 282 K and γ = 3.3 mJ mol–1 K–2, respectively, and are similar to those obtained for MgPd1.25Sb. There is neither phase transition nor superconductivity observed above 1.8 K. The differences between the electronic structures of Mg-based half-Heusler compounds make them robustly metallic, irrespective of the electron count and the introduction of interstitial transition metal (Pd) atoms.

An atmospheric pressure glow discharge in air stabilized by a magnetic field and its application on nitrogen fixation

AbstractAn atmospheric pressure glow discharge in air stabilized by a magnetic field is reported. The plasma is fixed at a position when the direction of the Lorentz force and the direction of the air flow is opposite. Under such condition, a stable glow discharge can be achieved and the plasma parameters can be independently controlled by the applied voltage, the magnetic field and the air flow rate, which is not the case for the widely used gliding arc (GA) discharge. For applied voltage of 6.5 kV, air flow rate of 2 L min−1, and magnetic field of 0.11 T perpendicular to the paper pointing outward, the discharge voltage (Vdis) and discharge current (Idis) are 1.2 kV and 49.7 mA, respectively. The rotational and vibrational temperature is about 3420 K and 4550 K, respectively. The electron density is on the order of 1014 cm−3 and the reduced electric field of plasma is about 36.9 Td, which is favorable for vibrational excitation of N2 to promote the production of NOx. As the plasma is fixed at a position, all the gas has to pass the plasma region and treated by the plasma when they are flowing, which is not the case for GA discharge where only a little percentage of gas is actually treated by the plasma. The energy cost of NOx production for the plasma stabilized by magnetic field of 0.19 T pointing outward is about 2.65 MJ mol−1, which is 41% lower than the GA discharge.

Pressure-Induced Intermetallic Charge Transfer and Semiconductor-Metal Transition in Two-Dimensional AgRuO 3

Pressure-Induced Intermetallic Charge Transfer and Semiconductor-Metal Transition in Two-Dimensional AgRuO ₃

Facile preparation of omniphobic PDTS-ZnO-PVDF membrane with excellent anti-wetting property in direct contact membrane distillation (DCMD)

Membrane distillation (MD) is a promising hybrid thermal/membrane desalination process to treat high salinity industrial wastewater with near-complete rejection of nonvolatile solutes. However, MD membrane still suffers the membrane wetting, which largely affects the desalination performance. In this study, a facile method includes one-step in-situ growth of ZnO nanorods and dip coating of low surface energy 1H,1H,2H,2H-perfluorodecytriethoxysilane (PDTS) was applied to fabricate omniphobic membrane (FZnO-PVDF) with excellent anti-wetting performance. The anti-wetting performance of FZnO-PVDF membrane was systemically evaluated by treating pure water, feed with surfactant and sparingly soluble salts for the first time. Theoretical analysis such as numerical simulation, dynamic liquid entry pressure (LEP) changes and nucleation condition was carried out to explain its anti-wetting mechanism. Results showed that FZnO-PVDF membrane displayed high contact angles towards water droplets with (∼121.1°) or without alcohol (∼164.9°), and low sliding angle for water (10.6°). The resultant membrane not only exhibited excellent resistance for surfactant-induced membrane wetting towards 0.6 mM sodium dodecyl sulfate (SDS) due to its enhanced LEP value (225 kPa), but also remarkable resistance for scaling-induced membrane wetting because of the high energy barrier for CaSO4 heterogeneous nucleation (34.2 mJ mol−1) and slip boundary condition of membrane. This study provides valuable insights for fabricating omniphobic membrane and comprehending its anti-wetting property in MD application.

Study of anisotropy in the superconducting properties of FeTe0.55Se0.45 single crystal grown by the self-flux method

We report anisotropy in the superconducting properties of FeTe0.55Se0.45 bulk single crystal synthesized via the self-flux method. We have performed magnetotransport, magnetic and heat capacity measurements on single crystals of same batch. The grown crystals have also been characterized by XRD, XPS and Raman measurements. The superconductivity at T C ∼ 14 K has been affirmed by the temperature-dependent resistivity, magnetic, and specific heat measurements. The anisotropy in the upper critical field (H C2), coherence length (ξ), and critical current density (J C) have been studied from the magnetotransport and magnetic measurements, respectively, under applied magnetic fields of 0–12 T along the ab-plane and c-axis. The critical current density has been estimated by Bean’s critical state model at different magnetic fields (J C(H)) and temperatures (J C(T)) measured for H‖ab-plane and H‖c axis. The anisotropic behaviour has also been observed for J C(H). The presence of ‘peak effect’ or fishtail characteristic has been noticed in M–H loops for H‖c only, which shows a shift towards the lower fields with increasing temperature. The nature of the pinning mechanisms in the sample has been determined by the normalized pinning force density using the Dew Hughes scaling rule, and the analysis of experimental data indicates the presence of δl-pinning in the sample. The temperature-dependent electronic specific heat has been fitted with the exponential law and the evaluated coupling constant 2Δ0/kBTc is ∼3.42 which is close to the universal BCS value of 3.53. The observed low value of residual Sommerfeld coefficient ≈ 4.59 mJ mol−1 K2 indicates good quality of the grown single crystal.

La2Pd2In: superconductivity and lattice properties at ambient and elevated pressures

Lattice and electronic properties of La2Pd2In were studied at ambient and elevated pressures so as to determine features related to a specific atomic coordination without any influence of magnetism. We describe temperature dependences of lattice parameters, heat capacity and electrical resistivity of single-crystalline La2Pd2In (s.g. P4/mbm) in a broad temperature range 0.09–300 K. Together with the anisotropic effect of hydrostatic pressure, showing that the lattice is more compressible in the basal plane, we can conclude that the lattice is affected by degrees of freedom of the La atoms with positions not imposed by symmetry. The lattice anisotropy is smaller than that found for isostructural ferromagnet Ce2Pd2In. The equilibrium bulk modulus B 0 = (48 ± 3) GPa was determined on the basis of individual linear compressibilities. Measurement of electrical resistivity indicated a superconducting state below T = 0.59 K with a low critical field 0.005 T at T = 380 mK. The onset of superconducting state as a bulk property of La2Pd2In was confirmed by measurements of specific heat and AC magnetic susceptibility. Experimental data can be accounted by first-principles electronic-structure calculations based on density-functional theory. The measured Sommerfeld coefficient γ = 10.6 mJ mol−1 K−2, only marginally exceeding the calculated γ = 9.34 mJ mol−1 K−2, indicates only weak electronic correlations.

Evidence of strong correlation and magnetotransport scaling in YbFe2As2

Study of normal-state behaviour of YbFe2As2 single crystals has been reported through transport, specific heat and magnetotransport measurements. The YbFe2As2 crystals have been synthesized by using melt growth aided method. It is found that Sommerfeld coefficient (γ = 213.16 mJ mol−1K−1) is strongly enhanced suggesting existence of heavy quasiparticles. Analysis of resistivity data at low temperature yields Fermi-liquid co-efficient (A) value of 5.47 × 10−5 Ω cm K−2. Evaluation of Kadowaki-Woods ratio (A/γ2 = 1.204 × 10−5 μΩ cm mole2mJ−2) indicates that the YbFe2As2 crystal is a strongly correlated metal. The scaling analysis of magnetoresistance (MR) has been carried out. We have observed from MR results that YbFe2As2 show quadratic behaviour on magnetic field up to 5 T and beyond that it shows linear nature. Additionally, the verification of Kohler's rule has been explored. The measurement of MR as a function of magnetic field (B) up to 8 T indicates that Kohler's rule is not satisfied in YbFe2As2. However, it is found that YbFe2As2 satisfies an unusual scaling relationship between applied magnetic field and temperature within limited temperature range, which was reported in other iron-based superconductors recently.

Discovery of superconductivity in Nb4SiSb2 with a V4SiSb2-type structure and implications of interstitial doping on its physical properties.

We report on the discovery, structural analysis, and the physical properties of Nb4SiSb2 – a hitherto unknown compound crystallizing in the V4SiSb2-type structure with the tetragonal space group I4/mcm and unit cell parameters a = 10.3638(2) Å and c = 4.9151(2) Å. We find Nb4SiSb2 to be a metal undergoing a transition to a superconducting state at a critical temperature of Tc ≈ 1.6 K. The bulk nature of the superconductivity in this material is confirmed by the observation of a well defined discontinuity in specific heat with a normalized specific heat jump of ΔC(Tc)/γTc = 1.33 mJ mol−1 K−2. We find that for Nb4SiSb2, the unoccupied sites on the 4b Wyckoff position can be partially occupied with Cu, Pd, or Pt. Low-temperature resistivity measurements show transitions to superconductivity for all three compounds at Tc ≈ 1.2 K for Nb4Cu0.2SiSb2, and Tc ≈ 0.8 K for Nb4Pd0.2SiSb2 as well as for Nb4Pt0.14SiSb2. The addition of electron-donor atoms into these void positions, henceforth, lowers the superconducting transition temperature in comparison to the parent compound.