Ti Cathode Research Articles

Polypyrrole-bound carbon nanotube conductive polysulfone membranes for self-cleaning of fouling

A novel conductive membrane, polypyrrole carbon nanotubes polysulfone (PPy-CNT-PSF), was successfully synthesized using the membrane phase infiltration in-situ polymerization method (MPIP). The resulting PPy-CNT-PSF, utilized as an anode in the electrochemical filtration reactor, exhibited a chain-like morphology of PPy extending from within to the exterior of the PSF membrane, effectively anchoring the CNT layer on its surface and establishing a stable conductive network with a surface resistance of 0.142 ± 0.052 kΩ/cm. Its electrical conductivity surpasses that of most conductive membranes derived from pyrrole (Py). Furthermore, the structural integrity of this conductive membrane remained intact following exposure to chlorine. Cyclic voltammetry (CV) analysis revealed a subtle redox peak with no significant alteration in surface structure after 50 CV cycles. This reaction can be attributed to a Fenton-like reaction process due to Fe presence detected by EDX on the surface. Current-time curves under constant potential further confirmed that the PPy-CNT-PSF conductive membrane possesses both a stable conductive network and favorable electrode stability. Additionally, self-cleaning occurred when voltage was applied during electrochemical experiments utilizing a conductive membrane anode paired with a Ti cathode due to electrostatic repulsive forces. At an applied voltage of 20 V, removal efficiency and flux restoration achieved values of 97.63 % and 100 %, respectively. This straightforward yet effective approach is believed to hold promise for fabricating conductive membranes characterized by structural stability and electrode reliability for practical applications aimed at mitigating membrane fouling.

Self-catalytic enhancement of Cu-EDTA decomplexation and simultaneous Cu recovery via a dual-cathode electrochemical process

Heavy metals that are readily chelated with coexisting organic ligands in industrial wastewaters impose threats to environment and human health but are also valuable metal resources. Traditional treatment methods generally require additional chemicals and generate secondary contaminants. Here, a reagent-free dual-cathode electrochemical system was proposed for the efficient destruction of Cu-organic complexes and synchronous cathodic recovery of Cu, whereby in situ production of H2O2 at carbon aerogel (CA) cathode was coupled with the reduction of Cu(II) to Cu(I) and finally to Cu(0) at Ti cathode. The intermediate Cu(II) complexes enabled the self-reinforced degradation owing to their higher activities toward •OH generation by activating H2O2 in contrast to initial Cu-ethylenediaminetetraacetic acid (Cu-EDTA). The enhanced production of Cu(I) by Ti cathode facilitated both •OH and Cu(III) formation, and the copper redox cycle was realized in the self-reinforced system, maintaining its sustainable catalytic activity. The energy cost of the dual-cathode system is 0.011 kWh/g for decomplexation and 0.057 kWh/g for Cu recovery, which is much lower than single Ti or CA cathode system. This established process provides a prospective approach for cost-effective destruction of chelating metal complexes and metal resources recovery from heavy metal wastewaters.

In situ evolution of electrocatalysts for enhanced electrochemical nitrate reduction under realistic conditions

Electrochemical nitrate reduction to ammonia (ENRA) is gaining attention for its potential in water remediation and sustainable ammonia production, offering a greener alternative to the energy-intensive Haber-Bosch process. Current research on ENRA is dedicated to enhancing ammonia selectively and productivity with sophisticated catalysts. However, the performance of ENRA and the change of catalytic activity in more complicated solutions (i.e., nitrate-polluted groundwater) are poorly understood. Here we first explored the influence of Ca2+ and bicarbonate on ENRA using commercial cathodes. We found that the catalytic activity of used Ni or Cu foam cathodes significantly outperforms their pristine ones due to the in situ evolution of new catalytic species on used cathodes during ENRA. In contrast, the nitrate conversion performance with nonactive Ti or Sn cathode is less affected by Ca2+ or bicarbonate because of their original poor activity. In addition, the coexistence of Ca2+ and bicarbonate inhibits nitrate conversion by forming scales (CaCO3) on the in situ-formed active sites. Likewise, ENRA is prone to fast performance deterioration in treating actual groundwater over continuous flow operation due to the presence of hardness ions and possible organic substances that quickly block the active sites toward nitrate reduction. Our work suggests that more work is required to ensure the long-term stability of ENRA in treating natural nitrate-polluted water bodies and to leverage the environmental relevance of ENRA in more realistic conditions.

Novel Cu(200)/Ti cathode for the enhancement of N2 selectivity in direct ammonia electrolysis: The controls of Cu cathode facet orientation

Direct electrochemical ammonia oxidation reaction (AOR) using NiCu-based anodes is effective in removing ammonia from wastewater. However, this type of anode frequently produces undesired byproducts NO3−. Here, we investigated three configurations of novel Cu/Ti cathodes (Cu(111)/Ti, Cu(200)/Ti, Cu(220)/Ti) coupled with Cu/Ni foam (Cu/NF) anode to enhance N2 selectivity (SN2) in a direct ammonia electrolysis cell. Cu(200)/Ti cathode improved SN2 from 35 % (bare Ti cathode) to 60 % and it achieved 10–15 % higher SN2 compared to Cu(111)/Ti and Cu(220)/Ti. The improvement of SN2 on Cu(200) facet was ascribed to the high nitrate electroreduction activity and its conversion to N2. In real wastewater, Cu/NF anode-Cu(200)/Ti cathode paired electrolysis system demonstrated its excellent capability of 88 % NH3 removal with 95 % SN2. Our electrolysis system was capable to maintain the residual NH3-N and the NO3-N below 8 mg L−1, meeting effluent discharge standards. Our findings highlighted the importance of the control of Cu cathode facet orientations for an efficient elimination of NO3– and improvement of N2 production during direct ammonia electrolysis.

Mechanism insights into H2O2in situ generation and activation for ciprofloxacin degradation by electro-peroxidation using the ACF@RuO2/Ti cathode

Electrocatalytic H2O2 production via the two-electron oxygen reduction reaction on the cathode surface plays a crucial role in the electro-peroxidation (EO-H2O2). In this work, the H2O2 generation potential of the EO-H2O2 process using an activated carbon fiber attached RuO2/Ti cathode (ACF@RuO2/Ti) was evaluated by simulation experiments with a high-precision syringe pump. Results shown that the actual average H2O2 accumulation rate reached up to 4.92 mg h−1 cm−2, while more than 95 % of the electrogenerated H2O2 was decomposed quickly. Electron paramagnetic resonance and quenching tests confirmed that the primary oxidant •OH was produced from H2O2 activation by ACF, RuO2 catalyst and their synergistic effect, while RuO2 played dominant role. The production of •OH in the EO-H2O2 process was also confirmed by the degradation and mineralization of antibiotic ciprofloxacin. The characterization results indicated that heterogeneous catalysis of cathode was due to both the pyridinic nitrogen and oxygen-containing groups of ACF, along with RuO2 catalyst on the RuO2/Ti surface. This study provides new insights into the mechanisms of the in situ H2O2 generation and activation in the EO-H2O2 process.

Sodium citrate enhancing electrodeposition of metallic arsenic from toxic trivalent arsenic and the mechanism understanding

Electrochemical conversion of hypertoxic trivalent arsenic to value-added metallic arsenic can not only contribute to pollution abatement, but also resources reutilization, therefore being widely explored. Electrochemical reduction of trivalent arsenic as a promising way is widely explored. However, the high efficiency conversion is retarded by the sluggish reduction kinetics of AsO33− and fierce evolution of side products of both H2 and toxic AsH3. Herein, by using the sodium citrate as the additive, the current efficiency for metal arsenic production is increased greatly from 60% to 91%, with the accompanied evolution of hypertoxic AsH3 being restrained from 0.15 Nm3/tAs to 0.022 Nm3/tAs, promising a high-efficiency and green process. The electrochemical tests and electrode surface characterizations as well as DFT calculations indicate that the added sodium citrate promotes both the diffusion of reactive AsO33− towards the cathode and its subsequent adsorption on the Ti cathode, contributing to smoother reduction for generating metal arsenic, with the evolution of toxic AsH3 being hindered at the same time. The results can provide new insights for the high-efficiency and greener conversion of hypertoxic trivalent arsenic to value-added metallic arsenic.

High-Performance and Stable Perovskite X-ray Detection and Imaging Based on a Ti Cathode.

High-energy radiation detectors with a good imaging resolution, fast response, and high sensitivity are desired to operate at a high electric field. However, strong ion migration triggered by electrochemical reactions at the interface between a high-potential electrode and an organic-inorganic hybrid perovskite limits the stability of radiation detectors under a high electric field. Herein, we demonstrate that such ion migration could be effectively suppressed in devices with a Ti cathode, even at a high electric field of 50 V mm-1, through time-of-flight secondary-ion mass spectrometry. X-ray photoelectron spectroscopy illustrates that Ti-N bonds formed at the interface of MAPbBr3 perovskite single crystals/Ti electrode effectively inhibit the electrochemical reaction in organic-inorganic hybrid perovskite devices and ultimately improve the operating stability under a high electric field. The device with a Ti electrode reaches a high sensitivity of 96 ± 1 mC Gyair-1 cm-2 and a low detection limit of 2.8 ± 0.3 nGy s-1 under hard X-ray energy.

Highly selective recovery of gold and silver from E-waste via stepwise electrodeposition directly from the pregnant leaching solution enabled by the MoS2 cathode

The recycling of electronic waste, i.e., waste Printed Circuit Boards (WPCBs), provides substantial environmental and economic advantages. In fact, the concentration of valuable precious and base metals in WPCBs is even higher compared to those found in mined ores. Nevertheless, it is still challenging to selectively extract precious metals with low concentrations from the pregnant leaching solution, due to the co-deposition of base metals, like Cu, which have higher concentrations. In this research, stepwise recovery of precious metals and copper directly from WPCBs thiosulfate leaching solution was facilitated by the Ti cathode coated with MoS2 (MoS2/Ti). The in-situ enrichment of Au(S2O3)23- and Ag(S2O3)23- at the surface of MoS2 enables the high efficiency and selectivity of electrodeposition, which has been confirmed through COMSOL Multiphysics simulations and visualization. As a result, the first-step electrodeposition at 0.6 V recovered 92.44 % Au and 98.18 % Ag without any co-deposition of Cu. Subsequently, the second-step recovery employed a constant current of 0.03 A, achieving 100 % recovery of copper within 12 h. Furthermore, this study optimized the reduction potential, NH3·H2O concentration, and S2O32- concentration for the stepwise electrodeposition process. These findings provide valuable insights for establishing a closed loop circular economy in the electronics industry.

Time-of-Flight Measurements in the Jet of a High-Current Vacuum Arc Thruster

Measurements of ion speed in the plume of a pulsed high-current vacuum arc thruster were performed by means of electrostatic probes. The probes were designed to provide direct speed measurements with minimum disturbance on the plasma jet. Typical mean values of vi for Ti and Cu cathodes are determined at different locations downstream of the electrodes, in the far field region. From one VAT discharge to another, the mean ion speed strongly varies which leads to a large statistical dispersion. Single-shot analysis allows the observation of the plume anisotropy and its high divergence as well as the existence of several ion groups of different speeds throughout a discharge.

Deposition of Ti[sbnd]Zr alloy films using Ti and Zr dual-cathode high-power impulse magnetron co-sputtering

In this study, titanium–zirconium binary alloy films were deposited using heterogeneous dual-cathode high-power impulse magnetron sputtering with a closed magnetron field. For both Ti and Zr cathodes, the discharge voltage pulses were synchronized with an equal pulse width. In addition, we investigated the effects of the average discharge power ratios of the two cathode materials, deposition pressure, and substrate bias voltage on the mechanical strength and microstructure of the deposited films. The results revealed that the film composition could be controlled by the average power ratio of the two cathodes at a constant deposition pressure; however, the deposition rate of each element varied with the deposition pressure. At a constant average power ratio at the two cathodes, the Zr content in the films decreased with decreasing the deposition pressure. Decreasing the deposition pressure can smoothen the film surface, but the dependence of the film composition on two cathode powers also changes. An adequate enhancement of the negative substrate bias can further increase the film hardness and reduce the film elastic modulus, yielding only a moderate loss in the film deposition rate and marginal variations in the film composition. However, the magnitudes of the increase in hardness and the decrease in elastic modulus brought by enhancing negative substrate bias varies with the film composition, and will be minimized when the atomic fractions of Ti and Zr are near equal. Notably, with adjusting the negative substrate bias, adding Zr can change the film hardness from 4.8 to 10.6 GPa, and the film elastic modulus from 100 to 162 GPa. Overall, the advantageous mechanical and structural properties of the TiZr alloy films deposited using HiPIMS might be useful in tools, biomedical devices, wearable equipment applications.

Study on the importance of the reductive degradation of GenX in its overall electrochemical degradation process on different cathode materials

Per- and polyfluoro alkylated substances (PFAS) are well known for their recalcitrant nature caused by the abundance of CF bonds. It has been proven that electrochemical degradation is a potentially suitable technique for treating PFAS; however, most studies solely focus on electrochemical oxidation, with limited attention given to electrochemical reduction, and the relative contribution of the two towards the total PFAS degradation has not yet been elucidated. This manuscript reports an investigation on the contribution of electroreduction to the overall electrodegradation of a target PFAS, HFPO-DA (i.e. GenX), using a boron doped diamond (BDD) anode and different cathode materials (Cu, Ti, Au). The oxidation and reduction reactions were successfully decoupled from each other and studied simultaneously using an electrochemical H-cell with an agar membrane. It was determined that reduction plays a significant role in the overall degradation of GenX for each of the cathodes studied, with its contribution ranging from 52 % for the Ti cathode, to 66 % for Cu, and to 92 % for Au.

Electrochemical reduction of aqueous nitrate using metallic silver particles as spatially suspended catalyst

Increasing nitrate concentrations in water sources is a serious concern. The current study demonstrates the electrochemical reduction of nitrate in the presence of silver metallic particles (AgMPs). Using Ti/RuO2 anode and a Ti cathode, nitrate removal in undivided and divided cells was limited to 18% and 77%, respectively, in the absence of AgMPs. Total Nitrogen (TN) removal in undivided and divided cells was nil and 29.5%, respectively, in the absence of AgMPs. Under identical conditions, the presence of 8 mM AgMPs increased nitrate removal to 63% and 99%, respectively, with significant improvement in nitrate conversion to N2. The effect of various parameters on nitrate removal and selectivity of products was studied using a divided cell: concentration of AgMPs, inter-electrode distance, cathode material, current density, initial nitrate concentration, and reusability of AgMPs. In the presence of 8 mM AgMPs, nitrate removal using different cathodes was Ti ≈ Fe > Cu > SS > Fe/Sn. The cathode type also affected the selectivity, with the maximum conversion to N2 achieved with the Ti cathode. Nitrate removal and conversion to N2 improved with the increase in current density up to 10 mA/cm2. Overall, the presence of AgMPs substantially improved nitrate removal and conversion to N2. The production of reductive species (AgHx) by the intercalation of nascent hydrogen on metallic silver appears to promote catalytic nitrate reduction. AgMPs could be reused up to 10 times with consistent performance. This work offers a new approach to nitrate reduction using an efficient and reusable catalyst.

Development of methods for controlling the quality of hypochlorous acid solution obtained by electrochemical synthesis

The article presents materials on developing quality control methods for hypochlorite acid obtained by electrochemical synthesis. Electrochemical synthesis of hypochlorous acid was carried out using a combined electrochemical-pyrolytic method. The electrocatalytic activity of the obtained materials in the hypochlorite acid synthesis reaction was evaluated under the electrolysis of 0.05 M NaCl solutions in a duct cell with a Ti cathode at 25 ºС. The cathode area was varied, so the cathode current density was 40 mA/cm2. The pH of the solutions was monitored with a pX-150MI universal ionometer. The volumetric current density in the channel cell was 2.4 A/dm3, and the volumetric rate of solution supply was 9.5 l/h. The authors developed an original method of iodometric titration, which is based on the sequential determination of the content of hypochlorite ions, their total content with chlorite ions, and the total content simultaneously with chlorite and chlorate ions. The content of individual components of the mixture is determined as the difference between the total content of ions and the content of hypochlorite ions. The iodometric method of titration of oxidants is based on the reaction of replacing oxygen-containing compounds of chlorine with elemental iodine with its subsequent titration with standard solutions of sodium thiosulfate. It is proposed to fix the endpoint of the titration potentiometrically, which allows you to speed up the analysis, and it is also relatively easy to automate it using an automatic titrator. The content of oxygen-containing compounds in the solutions depends on the oxidation conditions and the specified operating modes of the electrochemical catalyst. The solution's acidity determines the presence of hypochlorous acid and can be calculated based on the equilibrium constant of its dissociation. The developed analysis methods will allow the control of the quality of veterinary drugs based on hypochlorous acid obtained by electrochemical synthesis.

Characterization of Bismuth Composited to Carbon Nanotube-Coated Titanium Cathode in Electro-Fenton System

Bismuth (Bi) is a highly reactive catalyst for the generation of hydroxyl (∙OH) radicals. Cathodes constructed from composites of Bi and carbon nanotube (CNT) exhibit high stability and low resistance, which enhance their electron transfer capability. In this work, a titanium substrate was coated with multi-walled carbon nanotube (MWCNT/Ti) using electrophoretic deposition process, followed by electrodeposition of Bi onto the MWCNT-coated Ti (Bi/MWCNT/Ti). The effects of Bi electrodeposition time on the surface morphology of Bi/MWCNT/Ti cathodes were investigated by scanning electron microscopy and energy-dispersive X-ray spectroscopy, and the electrochemical characteristics of each cathode were identified via a series of electrochemical analyses further. The results demonstrated that electrodeposition at −0.85 V vs. Ag/AgCl for 5 min revealed uniform distribution of dense Bi across the surface of cathode, which provides better hydrophilicity for cathode and promotes highest electron transfer rates, respectively; when the Bi/MWCNT/Ti cathode was used as an electro-Fenton (EF) cathode, the EF system achieved a rhodamine B degradation rate of 80.8% after 30 min, which is a significant increase (83.63%) than the unmodified Ti cathode. The use of Bi in EF cathodes improves the efficiency of the EF process.

Study of the Structure and Mechanisms of Wear of Solid-Lubricant Coatings of the TiN–Pb System

Сomposite solid lubricating coatings TiN–Pb with a thickness of ~2 μm were produced by co-sputtering of Ti and Pb cathodes of two separate magnetrons on titanium alloy VT6. The Pb content in the coating averages ~12 at. %. The inner layer is coating characterized by a uniform distribution of Pb, and the upper layer is characterized by the presence of islands with a high content of Pb. The coating structure is globular, predominantly containing nanometer-sized crystallites. The absence of a columnar structure of the coating is associated with a high content of Pb, which is insoluble in the TiN matrix and interrupts the growth of crystallites. X-ray diffraction analysis showed the presence of Pb, PbO, and TiN phases in the coatings. The diffraction lines are broadened, which indicates that the crystallite size is ~10–20 nm in the coating. Tribological tests of the TiN–Pb coating were carried out under conditions of low-amplitude friction – fretting wear in a wide range of loading parameters. In the full slip mode, a friction coefficient of ~0.25 is observed. During the transition from the full slip mode to the reciprocating slip mode, the energy dissipated during friction drops by more than three times, which is also reflected in a sharp decrease in the friction coefficient from 0.25 to 0.05.

A coupling mechanism of anodic oxygen evolution reaction during organic pollutants oxidation

In this work, β-PbO2/Ti and RuO2-IrO2/Ti anodes and Ti cathodes were employed to conduct electrocatalytic phenol degradation experiments at various current densities. The difference in degradation rates between the two anodes indicated that the oxygen evolution reaction (OER) is related to the organic matter concentration. Consequently, a coupling mechanism “active-site competition mechanism (ACM) + adsorbate evolution mechanism (AEM)” for anodic oxygen evolution was described. Based on this mechanism and experimental results, it can be concluded that the ACM influences the initial degradation rate, and the AEM affects final organic matter concentrations. DFT calculations showed that RuO2-IrO2 exhibits excellent AEM activity attributed to the lower OER overpotential (0.7 V) and stronger adsorption energies of *O oxygenated intermediate (-1.52 eV). At the same time, RuO2-IrO2 possesses slight thermodynamic reaction energy of ACM, which are 103.3, 31.6 and 89.5 kJ/mol. Therefore, the slower degradation rates and lower removal efficiency on RuO2-IrO2/Ti are owing to the better ACM and AEM activity. Then, electrocatalytic experiments at various pH were conducted to verify the conclusion that AEM affects final organic matter concentrations. Finally, this work has implications for a better understanding of the OER mechanism and provides theoretical guidance for improving the removal efficiency of organic pollutants.

Enhanced photoelectrocatalytic oxidation of hypophosphite and simultaneous recovery of metallic nickel via carbon aerogel cathode

Carbon aerogel (CA) cathode was adopted to an undivided-chamber photoelectrocatalytic system with TiO2 nanotube arrays (TNA) photoanode to enhance the oxidation of hypophosphite (H2PO2−) and simultaneous recovery of metallic nickel (Ni). Both the efficiencies of H2PO2− oxidation and Ni recovery were significantly enhanced after replacing Ti or carbon fiber paper cathode with CA cathode. With 1.0 mM H2PO2− and 1.0 mM Ni2+, the ratio of PO43− production increased from ∼41% or ∼54% to ∼100%, and the ratio of Ni recovery increased from ∼20% or ∼ 37% to ∼93% within 180 min at 3.0 V. H2PO2− was finally oxidized to PO43− by •OH radicals, which was speculated to be generated from UV/H2O2 and bound on TNA photoanode. Meanwhile, Ni2+ was eventually electro-reduced to metallic Ni by a two-electron reduction reaction. The efficiencies of H2PO2− oxidation and Ni recovery were favored at higher cell voltage, faintly acid conditions and larger H2PO2− concentration. The stability of this system exhibited that the ratio of PO43− production increased significantly in each cycle, which was attributed to the increase of H2O2 in-situ-generation via CA cathode caused by deposition of metallic Ni. Finally, the treatment of actual electroless nickel plating effluents was demonstrated.

Performance Study and Assessment of Electrocatalytic Treatment of Substation Domestic Sewage

In China, the power grid construction process is accelerating. At the same time, the requirements for power grid water environment management are also constantly improving. There are a large number of substations and most of them are located in the countryside and surrounded by farmland. Therefore, it is important to treat the domestic sewage of the substation to meet the relevant standards. Recently, electrocatalysis technology has attracted much attention because of its high efficiency and no secondary pollution such as sludge. However, there are few reports on the application and performance evaluation of electrocatalytic treatment of domestic sewage in substations. Therefore, the experimental research aims to treat domestic sewage in substations reaching the corresponding standard. The optimal operating parameters and comprehensive performance assessment of the electrocatalysis technology are investigated, applying iridium-tantalum, ruthenium-iridium, boron-doped diamond anodes, titanium cathodes, and carbon fiber cathodes. The results show that the application of the three anodes can efficiently treat the sewage reaching the corresponding standard, indicating that electrocatalysis is suitable for the treatment of domestic sewage in substations. Moreover, comprehensively considering cost, treatment effect, energy consumption, and reaction temperature, the composite performance of iridium tantalum anode and Ti cathode is the best. In summary, this paper provides a comprehensive study and assessment of the performance of electrocatalytic treatment of domestic sewage in substations, providing theoretical support for the water environment management of power grids.

Numerical simulation on the impurity photovoltaic (IPV) effect in c-Si wafer-based dual-heterojunction solar cell

The impurity photovoltaic effect (IPV) with thallium (TI) impurity has theoretically been investigated in crystalline silicon (c-Si) wafer reigned dual-heterojunction (DH) solar cell that ensures an extended absorption of longer wavelength light with zinc selenide (ZnSe) window and aluminium antimonide (AlSb) back surface layers. The results imply that the incorporation of impurity enhances the photocurrent while the dual-heterojunction ensures the higher V OC of the proposed solar cell structure. The pristine Si (150 µm wafer) solar cell exhibits a power conversion efficiency (PCE) of 35.04% with J SC = 38.85 mA/cm 2 and V OC = 1.05 V, respectively. On the contrary, the introduction of Tl impurity within the bandgap of absorber enhances the PCE to 44.47%, with a J SC = 48.95 mA/cm 2 , V OC = 1.063 V and FF= 85.46%, respectively. This augmentations of the V OC and J SC and hence PCE is originated from the DH structure and longer wavelength light absorption due to impurity-assisted two-step photon upconversion phenomena in the solar cell. • IPV effect in an n + -p-p + Si DH solar cell with Tl impurity has been simulated. • ZnSe and AlSb have been used as window and BSF layers, respectively. • The optimized metal contacts Ti (cathode) and Ni (anode) has been established. • A maximum J SC of 48.95 mA/cm 2 and PCE= 44.47% with V OC = 1.063 V has been achieved. • n + - ZnSe /p- Si /p + - AlSb DH solar cell with Tl impurity shows potential in future.

Ion energy distribution of plasma ions of a hollow cathode discharge in Ar + N_2 and Ar + O_2 gas mixtures

A hollow cathode discharge with a Ti cathode and a positively biased ring anode was operated in Ar + N_2 or Ar + O_2 gas mixtures. The energy distribution of plasma ions is investigated with the help of energy-resolved mass spectrometry. Singly and doubly charged Ar^+ and Ar^{2+} ions and molecular N_2^+ or O_2^+ ions are the most abundant ionic species. The kinetic energy of all plasma ions is enhanced by a positive anode voltage.Graphical abstract