Pyrite Research Articles

Fast pedogenesis of tropical Technosols developed from dolomitic limestone mine spoils (SE-Brazil)

Technosols occur wherever human activity led to the construction of artificial soils. Attention has been given to the use of these soils as a strategy for mine reclamation. Nevertheless, research on pedogenesis of Technosols in the tropical environment is still missing. This study evaluated the pedogenetic evolution of artificial soils constructed with dolomitic limestone mine spoils, where sugarcane has grown over two (SC2) and six years (SC6), and pasture has grown over 20 years (P20). Chemical and physical soil characterization as well as detailed macro and micromorphological description were conducted. We observed specific pedogenetic processes, mainly evidenced by the micromorphological investigation, such as: pedoplasmation, rubification and melanization. Pedoplasmation led to aggregation and was more intense after 6 years of pedogenesis. Dissolution of iron nodules and pyrite oxidation caused rubification and color development especially after 6 years. In P20, the predominant pedogenetic process was melanization. High contents of organic carbon (>7.4%) were observed throughout this profile, due to the addition of organic matter by roots and the organo-mineral interaction probably mediated by calcium. As a result, this profile presented structure and color equivalent to a mollic horizon. Our data evidenced the high intensity of different pedogenetic processes and the fast evolution of tropical Technosols highlighting its potential for land reclamation.

Remediation of hexavalent chromium in contaminated soil using amorphous iron pyrite: Effect on leachability, bioaccessibility, phytotoxicity and long-term stability

A large amounts of arable land is facing a high risk of hexavalent chromium (Cr(VI)) pollution, which requires remediation using a low toxic agent. In this study, the remediation effect of amorphous iron pyrite (FeS2(am)) on Cr(VI) in Cr(VI)-contaminated soil was evaluated by systematically analyzing the variation of the leachability, bioaccessibility, phytotoxicity, and long-term stability of the remediated soil. The effectiveness of FeS2(am) on the leachability was assessed by alkaline digestion and the toxicity characteristic leaching procedure (TCLP); the effect on the bioaccessibility was evaluated via the physiologically based extraction test (PBET) and the Tessier sequential extraction; the effect on the phytotoxicity was assessed via phytotoxicity bioassay (seed germination experiments) based on rape (Brassica napus L.) and cucumber (Cucumis Sativus L.), and the long-term stability of the Cr(VI)-remediated soil was appraised using column tests with groundwater and acid rain as the influents. The results show that FeS2(am), with a stoichiometry of 4× exhibited a high efficiency in the remediation of Cr(VI) and decreased its leachability and bioaccessibility during the 30-day remediation period. In addition, seed germination rate, accumulation and translocation of Cr, and root and shoot elongation of rape and cucumber of remediated soil are not significantly different from those of clean soil, illustrating that FeS2(am) is suitable for remediating Cr(VI) contaminated arable soil. The stabilization of Cr(VI) in contaminated soil using FeS2(am) was maintained for 1575 days. The long-term effectiveness was further confirmed by the increasing amount of free Fe and Mn in the effluent and the decreasing redox potential. In summary, FeS2(am) has an excellent efficiency for the remediation of Cr(VI), demonstrating it is a very promising alternative for use in the contaminated arable soil.

Geochemical signatures of transgressive shale intervals from the 811 Ma Fifteenmile Group in Yukon, Canada: Disentangling sedimentary redox cycling from weathering alteration

Despite iron and trace element proxies informing much of our insight into Earth’s oxygenation history, the processes that controlled their accumulation and distribution in ancient sedimentary environments are not fully understood. Furthermore, deciphering between primary, depositional signals and oxidative weathering alteration poses a substantial challenge to reconstructing Earth’s redox history using its sedimentary record. Here, we present a multi-proxy geochemical investigation of three transgressive shale intervals from the ca. 811 Ma Reefal assemblage (upper Fifteenmile Group) in Yukon, Canada to help resolve these issues. Systematic stratigraphic trends from low to high FeHR/FeT and FeT/Al compositions across shale intervals represent shoaling of a discrete redoxcline that separated oxygenated surface waters from anoxic, ferruginous deep waters during marine transgression. In some cases, these trends are followed by a symmetric fall, which represents a full “transgressive-regressive cycle” of the redoxcline. The high proportion of glauconite to total illite indicate short-term oscillating redox conditions as the redoxcline migrated across the sediment-water interface during relative sea-level rise. These conditions invigorated dissimilatory iron reduction (DIR) within anoxic sediment pore waters, which released Fe(II) into the overlying water column where it was oxidized to iron oxy(hydr)oxide and shuttled downslope. High rates of DIR within sediment replete with highly reactive iron oxy(hydr)oxide and organic matter removed isotopically light, bio-available iron, rendering the residual sediment depleted in FeT/Al relative to the detrital baseline and enriched in 56Fe. The low iron content of the detrital flux to the basin (Fe/Al ∼ 0.3) rendered the sediment susceptible to changes in its bulk δ56Fe composition by modification of its authigenic components alone and enabled fractionation from DIR to drive bulk-rock δ56Fe values up to 0.8‰. Anomalously high concentrations of redox-sensitive elements in three samples (up to 5792 ppm Cr, 586 ppm Mn, 726 ppm Mo, and 3509 ppm Ni) and their relative distribution patterns show similarities to co-enrichment due to particulate shuttling within a weakly restricted basin. However, SEM-EDS element maps and large-area BSE image mosaics show the remains of framboidal pyrite “ghosts” with secondary enrichment of redox-sensitive elements. Thus, these geochemical trends in redox-sensitive trace metals most likely reflect mobilization and re-accumulation following pyrite dissolution during outcrop weathering. The low primary pyrite content and local transformation of pyrite iron to iron oxy(hdr)oxide suggest that δ56Fe and FeHR/FeT data were unaltered despite indications of pyrite weathering. Ultimately, this dataset elucidates key aspects of sedimentary redox cycling directly preceding evolutionary milestones and a major perturbation to the global carbon cycle and also provides a template for evaluating the effects of outcrop weathering on commonly used sedimentary redox proxies.

Layered iron pyrite for ultrafast photonics application

Abstract Two-dimensional (2D) transition metal dichalcogenide materials have attracted much attention in recent years due to their excellent electro-optical properties. FeS2, the ideal composition of iron pyrite, is a 2D transition metal dichalcogenide which has been potentially used in the electronic, optical, and chemical fields. On the other hand, the narrow band gap of FeS2 (≈0.96 eV) makes it very suitable and promising for the ultrafast application in near-infrared regimes. However, the potential application of FeS2 in laser technology has not been explored till now. Ultrashort pulse lasers have great applications in industry and science because of its stability, ease of operation, and portability. Passively mode-locked fiber lasers using 2D materials (such as MoS2, CuS2, and WS2) as saturable absorber are intensively investigated. Here, layered FeS2 has been characterized systematically. It is successfully applied in ultrafast photonics and plays a key component in the passively mode-locked laser for the first time. The single pulse can be obtained with 1.7-ps pulse duration, 1.89-nm spectral width, and fundamental repetition of 6.4 MHz at 1563 nm central wavelength. Through controlling the pump power, the evolution of the pulse train can be observed, which can be transformed from single pulse to bound states. Also, the harmonic mode-locked fiber laser is observed with the pump power high enough.

Soluble Fe release from iron-bearing clay mineral particles in acid environment and their oxidative potential

Soluble iron from atmospheric aerosol particles has toxicological effects on ambient environment due to their oxidative potential. However, the dissolution process and factors affecting this process are poorly understood. In this study, by solid phase characterization and aqueous dissolution experiments, we investigated the influence of acids, including HCl, H2SO4 and HNO3, and H+ concentration on iron dissolution rate, solubility and speciation of iron in chlorite, illite, kaolinite and pyrite. The dissolution of iron-bearing clay minerals, i.e. chlorite, illite and kaolinite, was a multi-stage process with a rapid rate in the initial stage and then decreasing rate in the following stages. In contrast, the regularly crystallized pyrite proceeded with an extremely rapid dissolution rate at very beginning and then remained almost constant. In all acid solutions, the dissolution rate was in the order of pyrite > illite > chlorite > kaolinite. H2SO4 was stronger than HCl and HNO3 in the destruction of mineral structures to release iron, while HNO3 dissolved more iron in pyrite (FeS2). High H+ concentration easily destroyed the mineral structures to release the structural or interlayer iron, whereas low H+ concentration increased the proportion of Fe (II) in clay minerals. Non-linear fitting of continuous dissolution models showed that the iron dissolution rates and iron redox speciation as functions of time were well predicted, with r2 > 0.99 for chlorite and illite, and r2 > 0.96 for kaolinite. Oxidative potential analysis proved that the dissolved iron possessed a considerable potential to generate reactive oxygen species.

Possible use of waste from marcasite jewelry industry as iron pyrite source incorporated with titanium dioxide for photodegradation of lignin under a halogen tungsten lamp

This paper observes the possibility of utilization of the marcasite waste (MW) from jewelry industry as pyrite FeS2 source for preparing the pyrite FeS2/titanium dioxide (TiO2) photocatalyst composite powder with simple method. The photocatalyst composite powder was fabricated by mixing the washed and milled MW with commercial TiO2 in ethanol and calcining at 300 °C for 4 h under low oxygen atmosphere. The particle was core–shell structure constructed of TiO2 shell and pyrite FeS2 core. Photocatalytic activity of the prepared powder, investigated by lignin degradation under irradiation by a halogen tungsten lamp, was higher than that of the commercial TiO2. This work provides an opportunity of waste recycling for removing organic matter from wastewater.

Amide-Assisted Synthesis of Iron Germanium Sulfide (Fe2GeS4) Nanostars: The Effect of LiN(SiMe3)2 on Precursor Reactivity for Favoring Nanoparticle Nucleation or Growth.

Olivine Fe2GeS4 has been identified as a promising photovoltaic absorber material introduced as an alternate candidate to iron pyrite, FeS2. The compounds share similar benefits in terms of elemental abundance and relative nontoxicity, but Fe2GeS4 was predicted to have higher stability with respect to decomposition to alternate phases and, therefore, more optimal device performance. Our initial report of the nanoparticle (NP) synthesis for Fe2GeS4 was not well understood and required an inefficient 24 h growth to dissolve an iron sulfide impurity. Here, we report an amide-assisted Fe2GeS4 NP synthesis that directly forms the phase-pure product in minutes. This significant advance was achieved by the replacement of the poorly understood hexamethyldisilazane (HMDS) additive and TMS2S by the conjugate base, lithium bis(trimethylsilyl)amide (LiN(SiMe3)2), and elemental S, respectively. We hypothesized that fragments of both TMS2S and HMDS had carried out the roles that Brønsted bases play in amide-assisted NP syntheses and were necessary for Ge incorporation. Convolution of this role with the supply of S in TMS2S caused the iron sulfide impurities. Separating these effects in the use of LiN(SiMe3)2 and elemental S resulted in synthetic control over the ternary phase. Herein we explore the Fe-Ge-S reaction landscape and the role of the base. Its concentration was found to increase the reactivities of the Fe, Ge, and S precursors, and we discuss possible metal-amide intermediates. This affords tunability in two areas: favorability of NP nucleation versus growth and phase formation. The phase-purity of Fe2GeS4 depends on the molar ratios of the cations, base, and amine as well as the Fe:Ge:S molar ratios. The resultant Fe2GeS4 NPs exhibit an interesting star anise-like morphology with stacks of nanoplates that intersect along a 6-fold rotation axis. The optical properties of the Fe2GeS4 NPs are consistent with previously published measurements showing a measured band gap of 1.48 eV.

In situ observations of thermally induced phase transformations in iron sulfide nanoparticles

Iron pyrite (FeS2) exhibits dynamic thermal stability and represents an ideal model system to probe complex phase transformations in materials. At elevated temperatures, the sublimation of S atoms from the FeS2 lattice results in a phase transformation to one of the many polymorphic forms of pyrrhotite, i.e., from Fe1-XS (where 0 ≤ X < 0.2) to stoichiometric FeS. The complex nature of this phase transformation remains relatively unexplored at the nanoscale. Here, we use in situ transmission electron microscopy (TEM) and in situ X-ray diffraction (XRD) to observe the phase transformation of ~150 nm pyrite nanoparticles to pyrrhotite in vacuum. Although the overall shape of the nanoparticles remains cubic, the crystal structure of the nanoparticles changes from cubic pyrite to hexagonal pyrrhotite at ~400–450oC, which is ~100–150oC lower than reported values of bulk pyrite. Interestingly, our in situ observations do not evidence a core-shell transformation model which has been reported for the phase transformation of bulk pyrite to pyrrhotite, indicating the role of shorter length scales for diffusion in nanoparticles, as well as the role of S vacancies that facilitate faster atomic diffusion and rearrangements. In addition, the heating ramp rate was found to influence the phase transition temperature with lower temperatures of transformation seen for higher heating rates indicating the role of kinetic effects on phase transformation. We expect our detailed insights will help advance the use of FeS2 nanoparticles in high-temperature applications including catalysis and high-temperature batteries.

Feasibility of band gap engineering of iron pyrite (FeS2) by codoping Os, Ru or Zn together with O

For increasing the band gap of iron pyrite (FeS2) to make it more suitable for photovoltaic applications, we calculated the structural, electronic and optical properties of pure FeS2 and doped systems M0.25Fe0.75O0.25S1.75 (M = Zn, Ru or Os) by first-principle within the GGA + U method. The results show that doping with Zn and O simultaneously decreases the band gap of the iron pyrite and thus makes Zn0.25Fe0.75O0.25S1.75 unusable for photovoltaic applications. Fortunately, doping with either Ru and O or Os and O simultaneously increases obviously the band gap of the iron pyrite and thus makes Ru0.25Fe0.75O0.25S1.75 and Os0.25Fe0.75O0.25S1.75 useable for photovoltaic applications. The optical properties of the iron pyrite are also improved by doping with either Ru and O or Os and O simultaneously, the red shift phenomena also make both Ru0.25Fe0.75O0.25S1.75 and Os0.25Fe0.75O0.25S1.75 promising for photovoltaic applications with large photovoltage and high device efficiency.

Facile synthesis of FeS2/PVP composite as high-performance electrodes for supercapacitors

Abstract Polyvinyl pyrrolidone (PVP) and iron pyrite (FeS2) films are good to enhance the electrochromic devices as they serve as a surface stabilizer, nanoparticle dispersant, growth modifier, and reducing agent. The synthesis of FeS2 with PVP provides an easy pathway for electrolyte penetration which can improve the electrochemical performances in supercapacitor applications. In this work, we report a facile single-step chemical bath deposition technique to synthesis the FeS2/PVP on Ni foam for the first time. The broad bean-like nanostructure of FeS2 is fully covered with PVP nanoparticles and formed like a coagulation nanostructure on Ni foam. The FeS2/PVP/NF composite was evaluated as an efficient electrode for supercapacitor in 3 M KOH solution, exhibited a greater specific capacitance of 526.08 F g−1 at 1 A g−1, high cyclic stability, remain 91.2% of the initial capacitance after 3000 cycles and high rate capability which is higher compared to bare FeS2/NF electrode (434.9 F g−1 at 1 A g−1 and cyclic stability of 76.7%). The remarkable electrochemical performance of FeS2/PVP/NF composite is attributed to its enhanced electroactive sites, higher surface area, fast electron, and ion transport pathway and most importantly for its facile electrolyte infiltration into the FeS2/PVP/NF.

Iron pyritization in shallow methane fields in sediments of the Ría de Vigo (NW Iberian Peninsula)

Iron pyritization in shallow methane fields in sediments of the Ría de Vigo (NW Iberian Peninsula)

A review of “pyrite disease” for paleontologists, with potential focused interventions

A review of “pyrite disease” for paleontologists, with potential focused interventions

Surface polarity, water adhesion and wettability behaviors of iron pyrite

Earth abundant iron pyrite (FeS2) has attracted considerable attention as a potential non-toxic absorber material in lieu of widely used but toxic and relatively rare Indium containing CIGS and CdTe for thin-film solar cells. Research in this regard has been progressed in understanding its fundamental electronic, optical and chemical properties, while its surface polarity is rarely been studied. In this contribution, we have investigated the adhesion of water to determine the wettability (i.e. hydrophilic or hydrophobic) of naturally grown FeS2, and thereof, the polarity of the surface. FeS2 has a cubic crystal structure that grows and cleaves along its cubic faces. Based on the measurements using Sessile drop method, we have found that the surfaces of the pyrite phase of FeS2 crystals are intrinsically super-hydrophilic and highly polar. Our finding is corroborated with X-ray diffraction, Fourier Transform Infrared, Raman Spectroscopy, particle size determination, and contact angle measurements of the pyrite phase. The surface polarity would be a critical factor for choosing surface passivation protocols and type of contact materials as well as for interpreting surface field effects in the system for solar cell application with material heterojunctions.

Présentation et intégration régionale des sépultures campaniformes de Trémery « ZAC de la Fontaine-des-Saints » site 19 (Moselle)

Site 19 Trémery ZAC de la Fontaine-des-Saints, which lies 14 km north-east of Metz, was excavated in 1999. The site is located on a slope on the right bank of the river Moselle. The site produced several occupation phases, dating from the Early Neolithic to the Early Iron Age and a group of four Bell Beaker graves, one of which was discovered during trial trenching. The burials are located in an area of around 500 m2 on the western edge of the site. A pit and a post-hole near the graves also produced residual finds dating to the Bell Beaker culture, possibly indicating other activities on the site during this period. The grave pits are generally of rectangular shape with rounded corners. As the pits are not very well preserved due to truncation, it was not possible to observe any of the burials’ external features. They contain single primary inhumations burials, in varying positions and with different grave goods. The state of bone preservation ruled out reliable sex diagnosis. The first burial discovered during trial-trenching contained an individual of unknown sex and age accompanied by a dagger made from local Secondary flint, a fragment of a retouched flake and two flakes, as well as a decorated vessel with a sinuous profile. While the dagger is a feature of early Bell Beaker burials, the incised pottery decoration, with its tripartite organisation, can be dated to the middle Bell Beaker period. Two of the graves discovered during excavation produced no finds. They contain the remains of individuals of indeterminate sex, an adult in extended position on the back (2113), a young adult lying on the right side (2154). The third burial (2105) is that of an adult with a flat-based beaker of mixed style, decorated with comb-impressed hatched bands bordered by cord impressions. Nine barbed-and-tanged arrowheads, typical of the western Bell Beaker area, were found on and around the body. They are made from a Cretaceous flint that could be from the Senonian outcrops in the Champagne area. Some of the blanks are Kombewa flakes. Three arrowheads grouped on the west side of the pit indicate a dismantled quiver, with the dispersion of the other arrowheads probably taking place after the burial. Lastly, a strike-a-light and a piece with an abrupt retouch were located under the thorax. A fragment of iron pyrite associated with these elements suggests that they made up a fire-lighting kit. The analysis of residues identified on the two sides of the strike-a-light reveals the presence of mineralised and oxidised organic matter consisting of bone fragments and traces of alder. The wood is apparently not from a hafting system, but could either be the remains of an arrow shaft or a container for the fire-lighting kit. The burial discovered during the trial trenching is later than the other three, due to the decoration style of its pottery. The radiocarbon dates from the three burials found during the excavation phase place them in the earliest Bell Beaker period, 2700 – 2450 BC. According to the chronological system established by L. Salanova, this grave group can be dated to stage 2 of the final Neolithic of Northern France (early Bell Beaker). During this early phase, the graves are mostly individual inhumations, which are isolated or loosely clustered, with no particular layout of the pit, nor preferential organisation in the position and orientation of the body. The grave group at Trémery clearly fits this model. The date obtained for grave 2105 is one of the earliest in the Paris Basin, 2582 – 2472 BC cal. (96% probability) or 2697 – 2455 BC cal. (94% probability). The characteristics of the grave-goods, previously observed in early Bell Beaker contexts, seem coherent with this radiocarbon date. This type of assemblage and the accumulation of arrowheads are nevertheless unusual, with few comparable examples in the region.

Iron-regulated NiPS for enhanced oxygen evolution efficiency

High-purity pyrite iron nickel monophosphosulfides (Ni1−xFexPS,x= 0, 0.1, 0.15, 0.2) were synthesized as efficient OER catalysts for the first time by a clean high-pressure and high-temperature (HPHT) technique.

Direct growth of FeS2 on paper: A flexible, multifunctional platform for ultra-low cost, low power memristor and wearable non-contact breath sensor for activity detection

This is the first demonstration of direct growth of iron pyrite (FeS2) via a single step hydrothermal route on low cost, biodegradable, flexible cellulose paper substrate which is further explored as a versatile multifunctional platform for memristor (with top and bottom electrodes) and wearable breath sensor (with planar contacts) which exhibits excellent switching and response respectively. XRD, EDAX studies confirmed the formation of crystalline pyrite FeS2. Memristor device exhibits excellent bipolar resistive switching mechanism at very low set, reset voltages i.e. +0.25 V, −0.5 V with a very low power consumption in the range of few micro to nano watts, decent switching ratio of 4 × 102, good data retention up to 2 × 104 s and excellent switching endurance up to 500 cycles. Furthermore, FeS2 grown on paper displayed excellent response towards exhaled breath exhibiting distinguished response towards oral and nasal breath. The sensor was employed in monitoring the exhaled breath pattern during dynamic movements like walking, running and jumping. The mechanism of sensing can be attributed to the conductivity and hydrophilic nature of sensor aiding in adsorption and desorption of the water molecules from the exhaled breath on to the FeS2 microspheres. The strategy outlined here, presents a low cost approach using iron and its pyrites which are abundant, non-toxic and also cost effective based flexible devices for multifunctional electronic applications.

Larger root nodules increased Fe, Mo, Mg, P, Ca, Mn, K in the roots and higher yield in chickpea grown from nano FeS2 pre-treated seeds: emulating nitrogenase

N2-fixing bacteria symbiotically dwell inside the root nodules of legume and converts atmospheric N2 to NH3. Unlike high temperature–pressure Haber’s process, this conversion in the nodule is orchestrated by nitrogenase: an enzyme with Fe-S, Fe-Mo, Fe-V cofactor, at its heart. Strategies to increase the nodule population could reduce nitrogen fertilizer use. Here we discovered that pre-treating the chickpea seeds with nano FeS2 (iron pyrite) resulted in a denser root network with larger root nodules. It improved the shoot system and resulted in a higher yield. We observed a higher concentration of Fe, Mo, Mg, P, Ca, Mn, K in the roots of chickpea: possibly emulating nitrogenase.

Phase-pure iron pyrite (FeS2) micro- and nano-sized crystals synthesized by simple one-step microwave-assisted hydrothermal method

Iron pyrite micro- and nano-sized crystals are desirable as active materials in lithium ion batteries and photovoltaics, and are particularly suitable for nanocrystal inks for roll-to-roll deposited or ink-jet printed solar cells. In this paper we report the synthesis of iron pyrite micro- and nano-sized crystals via simple and convenient green one-step microwave-assisted hydrothermal (M − H) process at relatively low growth temperatures, using commonly used precursors such as FeCl3, Na2S and S8 and. The structural, morphological and optical properties of the resulting nanostructured materials have been thoroughly investigated for two typical M − H growth temperatures. X-ray diffraction (XRD) pattern and Raman data revealed good crystalline quality for the as synthesized pyrite NCs. Typical XRD patterns show the dominant peaks which can be indexed as a pure cubic phase of FeS2, with lattice constant values close to the lattice parameters reported for FeS2, and in agreement with a stoichiometric pyrite phase. XRD and Raman analysis also confirm that no other impurities phases such as hexagonal FeS, marcasite, pyrrhotite, greigite, S or Fe–O compounds were detected, confirming the high purity of the synthesized iron pyrite nanocrystals. Various shapes of pyrite like quasi-cubic, cubic and flower-like FeS2 nanocrystals have been observed, which can be modulated by using different synthetic conditions. The sizes of the pyrite micro- and nanostructures were in the range of 150 nm to 1 μm as obtained. The present study indicates that the M − H method is a facile one-step way to obtain phase pure iron pyrite micro- and nano-sized crystals. Optical characterization confirms direct bandgap transitions (values of 2.61 eV and 2.55 eV for iron pyrite NCs samples hydrothermal grown at 130 °C and 160 °C, respectively), and indirect bandgap transitions (values of 1.19 eV and 1.52 eV for samples hydrothermal grown at 130 °C and 160 °C, respectively). Optical studies show high absorbance in the entire UV–Vis wavelength range making the as-synthesized pyrite nanocrystals potential candidate as absorber in nanoscale photovoltaic solar cells.

Temporal Changes of Pyrite Oxidation Rate in Bolivian Sulphidic Mining Wastes

Temporal Changes of Pyrite Oxidation Rate in Bolivian Sulphidic Mining Wastes

Nitrogen Reduction: Photoactive Earth‐Abundant Iron Pyrite Catalysts for Electrocatalytic Nitrogen Reduction Reaction (Small 49/2019)

Nitrogen Reduction: Photoactive Earth‐Abundant Iron Pyrite Catalysts for Electrocatalytic Nitrogen Reduction Reaction (Small 49/2019)