Zn Density Research Articles

Microstructure evolution and ductility improvement of additively manufactured biodegradable zinc–magnesium alloys via annealing

Zinc–magnesium (Zn–Mg) alloys, fabricated by laser powder bed fusion (LPBF) additive manufacturing techniques, have emerged as promising candidates for biomedical implants due to their biodegradation capability, superior mechanical strength, and excellent biocompatibility. However, LPBF-fabricated Zn–Mg alloys still face challenges related to extremely low ductility and limited exploration of degradation characteristics. In this study, the impact of Mg incorporation on the printability, degradation properties, microstructure, and mechanical properties of LPBF-fabricated Zn–Mg alloys was primarily investigated. Furthermore, we proposed a viable annealing post-processing route for the first time to tailor the microstructural characteristics of the fabricated Zn–Mg alloy and enhanced its limited ductility. The results demonstrated that by applying a laser power of 80 W and a scanning speed of 600 mm/s, the relative density of LPBF-fabricated Zn–Mg alloy reached 98.62%. Increasing the Mg amount from 1 to 5 wt% refined the grain size while promoting an increase in Mg2Zn11 and MgZn2 phases. Among these compositions, the Zn–1Mg alloy exhibited the greatest degradation rate at 0.126 mm/year. The annealing treatment facilitated the microstructure evolution of the Zn–1Mg alloy, resulting in equiaxed grains, increased average grain size, high-angle grain boundaries, and enrichment of Mg at grain boundaries. After annealing at 300°C for 0.5 h, the tensile strength of Zn– 1Mg alloy decreased from 254.92 to 170.93 MPa, while the elongation significantly increased by a factor of 14.3 from 0.55% to 8.43%. These findings provide valuable insights into an effective post-processing approach for tailoring the microstructure and resultant mechanical properties of LPBF-fabricated Zn and its alloys.

S-dopant and O-vacancy of mesoporous ZnO nanosheets induce high efficiency and selectivity of electrocatalytic CO2 reduction to CO

Surface engineering can adjust the electronic properties of catalysts, thereby boosting their electrocatalytic performances. Herein, S-doped and O-vacant mesoporous ZnO nanosheets (ZnO-VO-S) were synthesized through the plasma-treatment method, exhibiting highly electrocatalytic selectivity and activity in the conversion of CO2 to CO. Synchrotron X-ray absorption fine structure (XAFS) investigations were used to further clarify the valence state and local coordination structure of Zn, concretely affirming the reduced electron density of Zn in ZnO-VO-S. Specifically, at −1.1 V vs. RHE, the as-prepared ZnO-VO-S demonstrated a high Faradaic efficiency of 90%. Experiments and density functional theory (DFT) suggest that the electron deficiency of Zn caused by the introduction of S dopant and O vacancy, reduces the energy barrier of CO2 to CO by improving the adsorption behavior of the intermediate *COOH.

Zinc oxide and ferric oxide nanoparticles combination increase plant growth, yield, and quality of soybean under semiarid region

Zinc (Zn) and iron (Fe) malnutrition are global health challenges that need immediate attention. Hence, to address these issues, a two-pronged approach involving the development and application of novel Zn and Fe products for crop fertilization may be a potential solution. Therefore, zinc oxide (ZnO) (∼13.2 nm) and ferric oxide (Fe2O3) (∼15 nm) nanoparticles (NPs) were synthesized and characterized. Seven nutrients treatments viz, control, ZnO- NPs (25 mg kg−1), Fe2O3-NPs (25 mg kg−1), ZnO + Fe2O3-NPs (25 mg kg−1each), ZnSO4 (55.8 mg kg−1), FeSO4 (60.4 mg kg−1) and ZnSO4+ FeSO4 (55.8 and 60.4 mg kg−1) were arranged in five-time replicated Completely Randomized Design model to test the effectiveness of ZnO and Fe2O3 NPs in two soybean cultivars over conventional zinc sulfate (ZnSO4) and ferrous sulfate (FeSO4) fertilizers. The results indicated that the photosynthetic rate (Pn) and chlorophyll content increased (33.9–86.2%) significantly at the flowering stage with ZnO and Fe2O3 NPs applications, compared to their conventional counterparts. Likewise, the combined application of ZnO and Fe2O3 NPs reduced H2O2 production by 17–19% and increased the superoxide dismutase (SOD) and catalase (CAT) activities by 15–17% and 9.6–11.4% over the combined use of ZnSO4 and FeSO4, respectively. The normalized difference vegetation index (NDVI) showed an increase of 6.9–44.2% under ZnO and Fe2O3 NPs, as well as ZnSO4 and FeSO4. Furthermore, the combined application of NPs enhanced soybean seed yield by 4.6–18.3% compared to conventional Zn and Fe fertilizers. Concerning seed Zn and Fe density, conjoint application of ZnO and Fe2O3 NPs increases Zn by 1.8–2.2-fold and Fe by 19.22–22.58% over the combined application of Zn SO4 and FeSO4, respectively. While the application of NPs significantly decreased seed phytic acid concentrations by 7.3–59.9% compared to the control. These findings suggest that the combined application of ZnO and Fe2O3 NPs effectively enhances soybean productivity, seed nutrient density, and overall produce quality. Therefore, the combined application of ZnO and Fe2O3 -NPs in soybean can be a potential approach for sustainable soybean production and to reduce/arrest Zn and Fe malnutrition in a growing population.

N vacancies modulated Zn single atoms for efficient H2O2 photosynthesis

The adjacent N vacancies increase the electron density of Zn–N4 and enhance the separation and migration of electron–hole pairs. The optimized sample exhibits a H2O2 yield, 3.2 times higher than CN.

Edaphic properties as pieces of evidence of tailings deposit on soils

Mine tailings are one of the primary contaminant sources of heavy metals and metalloids in the soil. Besides increasing the concentration of potentially toxic elements (PTEs), tailings may modify the edaphic conditions and decrease the buffer capacity of impacted soils. The influence of tailings may reach distances far from the impoundments depending on the transport path and the specific transport mean: air, rain (runoff and infiltration), or acid mine drainage. In this study, soil samples from various horizons were collected in trial pits along a transect, at different distances from sulfide tailings. Soil analysis included texture, organic matter, alkalinity, porous space, carbonates, pH, electrical conductivity, real density, apparent density, total sulfur, main mineralogy, and total concentrations of As, Cd, Pb, Fe, and Zn. Graphical and statistical interpretation of the results showed that real density and porous space are the leading indicators of the tailings dispersion and accumulation and that pH is not a significant parameter (all values were above the neutrality) due to the limestone abundance in the area. However, Zn and Cd concentrations had an inverse relation with pH. Differences in the concentrations of PTEs between the superficial and deep layers that increased toward the tailings were also observed. Gypsum was only present in the closest samples to the tailings and may also be an indicator of tailings’ influence on soils. This study allowed us to identify general edaphic parameters as a first and quick means to determine the tailings contamination of soils.

Investigation of ZnCoP coating electrodeposited on Q235B steel and its corrosion resistance in simulated acid rain solution

In order to further improve the corrosion resistance of Q235B steel used for sports equipment, the Zn coating, ZnCo coating, and ZnCoP coating are electrodeposited respectively on the Q235B steel. The relationship between corrosion resistance, surface morphology, structure, and surface roughness of different coatings is studied. All the electrodeposited coatings are crystalline with typical diffraction peaks. Three diffraction peaks of Co(111),Co(200), and Co(220) can be observed on the XRD pattern of ZnCoP that indicate that the addition of sodium hypophosphite in the plating solution is conducive to the electrodeposition of cobalt. The Zn coating shows strip-like surface morphology with the roughest surface (1.431 µm) while the ZnCo coating and ZnCoP coating are both composed of granular structures with compact surfaces. Compared with all the coatings, the corrosion current density of Zn coating is about 345.78 μA/cm2 which is the largest indicating poor corrosion resistance. The corrosion current density of ZnCo coating and ZnCoP coating is 47.83 μA/cm2 and 15.63 μA/cm2 respectively which are both lower than that of Q235B. The ZnCoP coating has the best corrosion resistance due to phosphorus and cobalt doped in the coating that refine the grain size and improve the surface compactness.

Proof of concept and early development stage of market-oriented high iron and zinc rice expressing dicot ferritin and rice nicotianamine synthase genes

Micronutrient deficiencies such as iron (Fe), zinc (Zn), and vitamin A, constitute a severe global public health phenomenon. Over half of preschool children and two-thirds of nonpregnant women of reproductive age worldwide have micronutrient deficiencies. Biofortification is a cost-effective strategy that comprises a meaningful and sustainable means of addressing this issue by delivering micronutrients through staple foods to populations with limited access to diverse diets and other nutritional interventions. Here, we report on the proof-of-concept and early development stage of a collection of biofortified rice events with a high density of Fe and Zn in polished grains that have been pursued further to advance development for product release. In total, eight constructs were developed specifically expressing dicot ferritins and the rice nicotianamine synthase 2 (OsNAS2) gene under different combinations of promoters. A large-scale transformation of these constructs to Bangladesh and Philippines commercial indica cultivars and subsequent molecular screening and confined field evaluations resulted in the identification of a pool of ten events with Fe and Zn concentrations in polished grains of up to 11 μg g−1 and up to 37 μg g−1, respectively. The latter has the potential to reduce the prevalence of inadequate Zn intake for women of childbearing age in Bangladesh and in the Philippines by 30% and 50%, respectively, compared to the current prevalence. To our knowledge, this is the first potential biotechnology public-sector product that adopts the product cycle phase-gated approach, routinely applied in the private sector.

In-situ regulated competitive proton intercalation and deposition/dissolution reaction of MnO2 for high-performance flexible zinc-manganese batteries

Due to the limitation of energy density caused by the one-electron reaction and capacity loss caused by the Mn(Ⅲ) disproportionation reaction, it is difficult to realize the synchronous improvement of energy density and cycle performance of Zn//MnO2 secondary batteries. Here, a competition mechanism is designed for the zinc-manganese battery to achieve both improved energy density and cycling stability by coupling a high crosslinking density hydrogel electrolyte (HCH) with MnO2 deposition and dissolution reaction. Compared to conventional aqueous electrolytes (2 M ZnSO4, 0.2 M MnSO4), the ultrathin HCH (101 μm) widens the battery's voltage window to 2.4 V without significantly increasing the weight of the electrolyte. HCH not only broadens the voltage window but also effectively delays the proton shuttle from cathode to anode, providing a favorable environment for MnO2/Mn2+ reversible cyclic reaction. The Zn//MnO2 battery achieved an energy density of 858 Wh/kgα-MnO2 and a stable cycle of 7000 cycles due to the limitation of disproportionated reactants by the in situ deposition and dissolution of MnO2 at the cathode.

Metal monovacancy-induced spin polarization for simultaneous energy recovery and wastewater purification

Simultaneous hydrogen generation and pollutants removal is considered as the potential solution to the energy and environmental crisis, which can cut the consumption of expensive sacrificial electron donors and reduce the ecotoxicity of wastewater containing pollutants. However, the integration of two redox half-reactions in one system is still a challenge, limited by irreconcilable reaction conditions and low kinetics. In this study, ZnO with abundant metal monovacancies (Zn-V-m) was fabricated to manipulate the spin state by tailoring the electron occupancy of eg-orbitals, which simultaneously endowed the material with both outstanding photocatalytic oxidation and reduction performance. Compared with pristine ZnO, the prepared Zn-V-20 increases the H2 production rate by 56.4-fold and enhances the pollutants removal efficiency by 27.5-fold. It is impressive that simultaneous hydrogen generation and pollutants degradation in one system is accomplished and accelerated. Furthermore, Zn L-edge X-ray absorption spectra (XAS) and density functional theory (DFT) calculations suggest that low electron occupancy of eg-orbitals optimizes the spin structure and leads to spin polarization, which provides the critical motivation for enhancing photocatalytic performance. This work accelerates the reaction rates of pollutants degradation and hydrogen generation at the surface interface by manipulating electron spin polarization, guiding the rational design of TMO-based catalysts for simultaneous energy recovery and wastewater purification.

Boosting the Electrocatalytic Oxygen Evolution of Perovskite LaCo1- x Fex O3 by the Construction of Yolk-Shell Nanostructures and Electronic Modulation.

Realizing the rational design of perovskite oxides with controllable compositions and nanostructures remains a tremendous challenge for the development of efficient electrocatalysts. Herein, a ligand-assisted synthetic strategy to fabricate perovskite oxidesLaCo1- x Fex O3 with yolk-shell nanostructures is developed. Benefiting from the unique structural and compositional merits, LaCo0.75 Fe0.25 O3 exhibits an overpotential of 310mV at a current density of 10mAcm-2 and long-term stability of 100 h for the oxygen evolution reaction. In situ Raman spectroscopy demonstrates that Fe substitution facilitates the pre-oxidation of Co sites and induces the surface reconstruction into active Co oxyhydroxides at a relatively lower applied potential, guaranteeing excellent catalytic performances. Density functional theory calculations unravel that the appropriate introduction of Fe into perovskite LaCoO3 leads to the improved electroactivity and durability of the catalyst for the oxygen evolution reaction (OER). Fe-3d orbitals show a pinning effect on Co-3d orbitals to maintain the stable valence state of Co sites at the low overpotential of the OER. Furthermore, Zn-air batteries (ZABs) assembled with LaCo0.75 Fe0.25 O3 display a high open circuit potential of 1.47V, superior energy density of 905Whkg-1 Zn , and excellent stability in a large temperature range. This work supplies novel insights into the future developments of perovskite-based electrocatalysts.

Microstructural evolution and mechanical properties of pure Zn fabricated by selective laser melting

There are few studies on the microstructure formation mechanism and microstructure evolution of selective laser melting (SLM) of pure Zn. In this study, the process parameters of SLM pure Zn were optimized first, and the effect of process parameters on its mechanical properties was explored. With the increase of laser energy density, the strength and ductility of the SLM Zn were improved. The formation mechanism and evolution law of SLM Zn were also explored. The microstructure of SLM pure Zn was equiaxed grains and lamellar structure. The formation of equiaxed grains was due to the low temperature gradient and high scanning speed of SLM pure Zn, which is finally located in the E area of the CET transition. This paper mainly clarifies the microstructure formation mechanism and evolution law of selective laser melting of pure Zn, and provides theoretical bases for the application of SLM pure Zn in medical implants.

High energy-power density Zn-ion hybrid supercapacitors with N/P co-doped graphene cathode

By combining the large power density of supercapacitors with the high energy density of ion batteries, a novel zinc-ion hybrid supercapacitor (ZHSC) is proposed and considered a promising candidate. But there are still challenges in the selection and application of reliable cathode materials. Herein, we used a mature and safe one-step hydrothermal method to synthesize N/P co-doped graphene (NPG), which exhibited a unique three-dimensional structure and a large specific surface area, showing great advantages as cathode to assemble Zn//NPG ZHSC with zinc foil. In the 1 M ZnSO 4 solution, the ZHSC shows superior electrochemical performance, which presents an excellent specific capacitance of 210.2 F g −1 under a wide working voltage of 1.8 V, and it achieves both a maximum energy density of 94.6 Wh kg −1 and a large power density of 4500 W kg −1 . More importantly, the capacitance retention rate remains 82% and a coulomb efficiency of ∼100% is achieved after 15,000 cycles. Overall, the results of this study highlight the efficient synthesis and excellent performance of NPG cathode materials, and also promote the rapid development and great application of high-performance Zn-ion hybrid capacitors. • The N/P co-doped graphene shows a high specific capacitance in ZnSO 4 solution. • Zn-ion hybrid supercapacitor is assembled by Zn//ZnSO 4 //NPG. • The excellent energy and power density of Zn//ZnSO 4 //NPG are achieved.

Enable commercial Zinc powders for dendrite-free Zinc anode with improved utilization rate by pristine graphene hybridization

Uncontrollable dendrite growth and side reactions that arise at the Zn anode severely impede the commercial applications of Zinc ion batteries. In particular, the low utilization rate of Zinc metal often results in low energy density. Herein, a more practicable non-dendrite zinc anode was designed to replace traditional zinc foils by hybridization of commercial zinc powders and pristine graphene (PG). The formed three-dimensional PG network not only enhance adhesion between zinc powder particles forming stable Zn powder/PG hybrid electrode with enough mechanical strength but also uniformize the local electrical field as a redistributor, leading to non-dendritic Zinc metal plating/stripping in combination with crystalline plane induce effect of PG. As a result, extremely low voltage hysteresis of 89 mV and long cycle life over 360 h (vs. 349 mV and 30 h for zinc foil) at large current density of 5 mA cm−2 are achieved for the Zn powder/PG anode. Notably, the Zn powder/PG anode can obviously enhance the rate performance and entire energy density of Zn||MnO2 full battery by nearly two times because of the higher utilization of Zn powder/PG anode. Therefore, this work provides new insight for designing practical zinc anode for high specific energy ZIB devices.

Investigations of Mn introduced structural modifications on Ni-doped ZnO diluted magnetic semiconductors and improved magnetic and antibacterial properties

Zn0.98Ni0.02O (Z1), Zn0.97Ni0.02Mn0.01O (Z2), and Zn0.96Ni0.02Mn0.02O (Z3) NPs had been synthesized by the co-precipitation method. The X-ray diffraction spectra revealed that synthesized NPs exhibited hexagonal wurtzite structure. At initial Mn concentration, Mn co-doping alters the cell parameter ‘a’ alone, while there was no change in ‘c’. The morphology of NPs was analysed using FESEM analysis and chemical compositions were confirmed through EDAX spectra. The valence state and composition of Zn, Mn, Ni, and O elements at the surface of Z3 NPs were analysed by XPS. FTIR spectra showed that the absorption corresponding to Zn–O stretching had been observed around 442 cm−1 and the peak was shifted towards a higher wavenumber side by Mn co-doping. A UV emission corresponding to NBE and defects related to visible emission were noticed in the photoluminescence spectra. The simultaneous addition of Ni and Mn enhanced the magnetization by increasing the charge carrier density and by controlling the interstitial Zn density. Antibacterial tests were carried out against (G+) S. aureus and (G-) E. coli bacterial strains and all NPs inhibited the bacterial growth.

Zinc transport in rice: how to balance optimal plant requirements and human nutrition.

Zinc (Zn) is an essential micronutrient for both plants and animals, while its deficiency in crops and humans is a global problem that affects both crop productivity and human health. Since plants and humans differ in their Zn requirements, it is crucial to balance plant nutrition and human nutrition for Zn. In this review, we focus on the transport system of Zn from soil to grain in rice (Oryza sativa), which is a major dietary source of Zn for people subsiding on rice-based diets. We describe transporters belonging to the different families that are involved in the uptake, vacuolar sequestration, root-to-shoot translocation, and distribution of Zn, and discuss their mechanisms of regulation. We give examples for enhancing Zn accumulation and bioavailability in rice grains through the manipulation of genes that are highly expressed in the nodes, where Zn is deposited at high concentrations. Finally, we provide our perspectives on breeding rice cultivars with both increased tolerance to Zn-deficiency stress and high Zn density in the grains.

Device simulation of FASnI3 based perovskite solar cell with Zn(O0.3, S0.7) as electron transport layer using SCAPS-1D

Zinc oxy-sulphide (ZnO 1-x S x ) has proven to be the most promising material for electron transport layer (ETL) as a replacement of CdS in thin film and perovskite solar cells due to its ability to tune the bandgap energy (2.7–3.8 eV). FASnI 3 (CH 4 N 2 SnI 3 ) based perovskite solar cells are found to be more efficient and stable than their MASnI 3 counterparts because of its wider bandgap (1.41 eV) and better temperature stability. In this paper, FASnI 3 based perovskite solar cell employing zinc oxy-sulphide (Zn (O 0.3 , S 0.7 )) as ETL and copper thiocyanate (CuSCN) as HTL is presented. The proposed structure FTO/Zn(O 0.3 , S 0.7 )/FASnI 3 /CuSCN/Au has been simulated using SCAPS-1D software. The parameters from various experimental and theoretical reported works were used to simulate the proposed solar cell and it resulted in 14.46% of power conversion efficiency (PCE). In order to investigate the impact of active layer on the performance of the proposed device, the parameters of active layer like thickness and defect density have been varied. Furthermore, parameters such as electron affinity, doping density and thickness of ETL and HTL respectively have also been varied to examine their influence on the output device parameters and optimized results deduced accordingly. Finally, the device simulation with the optimized parameters has resulted in improved output parameters with V OC of 1.0859 V, J SC of 28.12 mAcm −2 , FF of 84.96% and PCE of 25.94%, thus, paving the way for novel perovskite solar cells employing tin which are environmentally safe being lead free and have efficiency comparable tothe lead based counterparts. • FASnI 3 based lead free PSC with Zn (O 0.3 , S 0.7 ) as an ETL in n-i-p configuration is presented. • The effect of Zn (O 0.3 , S 0.7 ) ETL on PSC performance by SCAPS-1D simulation is investigated. • Variation in electron affinity, CBO, doping density and thickness of Zn (O 0.3 , S 0.7 ) on the performance of PSC is analysed. • Conclusive PSC Parameters thus obtained are: V OC -1.0859 V, J SC -28.12 mAcm −2 , FF-84.96% and PCE-25.94%.

Are the modern-bred rice and wheat cultivars in India inefficient in zinc and iron sequestration?

Zinc and iron deficiency is a serious global health problem in humans depending on cereal-diet and is largely prevalent in low-income countries like Sub-Saharan Africa, and South and South-east Asia. We report inefficiency of modern-bred cultivars of rice and wheat to sequester those essential nutrients in grains as the reason for such deficiency and prevalence. To substantiate, experiments were conducted with elite, high-yielding cultivars of rice (n = 16) and wheat (n = 18) released in succeeding decades since the beginning of green revolution in India. The inherent Zn and Fe sequestering capacity in grains of the cultivars, and their responses to external application of Zn and Fe fertilizers were evaluated following standard protocols. We found a downward trend in grain density of Zn and Fe in those cereals in past more than 50 years. However, we failed to notice yield-dilution as a causative effect for such unwitting downward trend. With time, the cultivars again became stubborn to Zn and Fe fertilization for enhancing their grain density. Further, we noticed that external supply of one element, to improve its density in grains, had inhibitory effect on accumulation of the other, and the effect was magnified along the succeeding decades. Our innovative research warrants an improvement in ionomes of the cereals to alleviate the said incapacitating effect and ultimately the deficiency of those elements in humans, particularly living in low-income countries.

Effect of the junction barrier on current–voltage distortions in the Sb2Se3/Zn(O,S) solar cells

A spike-like energy level alignment of Sb2Se3 absorber with a Zn(O,S) buffer layer is one of the crucial features for high efficiency solar cells based on Sb2Se3/Zn(O,S) heterojunction combination. Zn(O,S) has been considered a suitable substitute for the conventional CdS buffer layer in the Sb2Se3 solar cells. Because of the wider bandgap of Zn(O,S), more blue photons are collected, and consequently higher photocurrent is achieved. However, in some cases, distortions are observed in the current–voltage (J–V) characteristic in Sb2Se3 solar cells with Zn(O,S) buffer layer. In this paper, a simple approach is used to describe the effect of the junction barrier at Sb2Se3/Zn(O,S) interface on distortions in J-V curves. The results show that the junction barrier at Sb2Se3/Zn(O,S) interface is strongly affected by the conduction-band offset (CBO), whose height is varied depending on the carrier density of Zn(O,S), sulfur fraction in Zn(O,S), and operating temperature. The presence of a large junction barrier at Sb2Se3/Zn(O,S) interface leads to both red kink and crossover distortions, which are eliminated with increasing carrier density of Zn(O,S), increasing operating temperature, and decreasing sulfur content in Zn(O,S). The distortion-free and well-behaved J-V curves improve the performance of Sb2Se3/Zn(O,S) solar cells.

Food Consumption and Nutrient Density of Adults Male Aged 19-49 Years Old in Indonesia

The objectives of this study was to analyze food consumption and nutrient density of adults male aged 19-49 years old in Indonesia. This study was carried out through analyzing a consumption data set of Total Diet Study (SDT) of Indonesian Ministry of Health which were collected using 24-hour food recall method. The final subjects included for this study were 26268 male. The nutrients adequacy were assessed based on Institute of Medicine calculation. The nutrients analyzed include energy, protein, calcium, iron, zinc, vitamin A and vitamin C. The average food consumption of Indonesian adult male population is mostly from the grains food group of 305.0 g. The food group that was consumed the least by the adult population was oily seeds as much as 18.1 g. The adequacy of energy, protein, calcium, iron, zinc, vitamin A and vitamin C were 81.4%, 108.3%, 105.5%, 159.4%, 64.8%, 107.7% and 54.6%, respectively. The nutrient density of protein, Ca, Zn, vitamin A and vitamin C were still under the recommendation. It means that food consumption quality of Indonesian adults need to be improved. Considering the inadequate intake of some micronutrients in Indonesian adults male, it is necessary to increase the consumption of animal food, legumes, fruits and vegetables as sources of micronutrients.

High‐Throughput Electron Diffraction Reveals a Hidden Novel Metal–Organic Framework for Electrocatalysis

AbstractMetal‐organic frameworks (MOFs) are known for their versatile combination of inorganic building units and organic linkers, which offers immense opportunities in a wide range of applications. However, many MOFs are typically synthesized as multiphasic polycrystalline powders, which are challenging for studies by X‐ray diffraction. Therefore, developing new structural characterization techniques is highly desired in order to accelerate discoveries of new materials. Here, we report a high‐throughput approach for structural analysis of MOF nano‐ and sub‐microcrystals by three‐dimensional electron diffraction (3DED). A new zeolitic‐imidazolate framework (ZIF), denoted ZIF‐EC1, was first discovered in a trace amount during the study of a known ZIF‐CO3‐1 material by 3DED. The structures of both ZIFs were solved and refined using 3DED data. ZIF‐EC1 has a dense 3D framework structure, which is built by linking mono‐ and bi‐nuclear Zn clusters and 2‐methylimidazolates (mIm−). With a composition of Zn3(mIm)5(OH), ZIF‐EC1 exhibits high N and Zn densities. We show that the N‐doped carbon material derived from ZIF‐EC1 is a promising electrocatalyst for oxygen reduction reaction (ORR). The discovery of this new MOF and its conversion to an efficient electrocatalyst highlights the power of 3DED in developing new materials and their applications.