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Developing efficient metal‐nitrogen‐carbon (M‐N‐C) single‐atom catalysts for oxygen reduction reaction (ORR) is significant for the widespread implementation of Zn‐air batteries, while the synergic design of the matrix microstructure and coordination environment of metal centers remains challenges. Herein, a novel salt effect‐induced strategy is proposed to engineer N and P coordinated atomically dispersed Fe atoms with extra‐axial Cl on interlinked porous carbon nanosheets, achieving a superior single‐atom Fe catalyst (denoted as Fe‐NP‐Cl‐C) for ORR and Zn‐air batteries. The hierarchical porous nanosheet architecture can provide rapid mass/electron transfer channels and facilitate the exposure of active sites. Experiments and density functional theory (DFT) calculations reveal the distinctive Fe‐N2P2‐Cl active sites afford significantly reduced energy barriers and promoted reaction kinetics for ORR. Consequently, the Fe‐NP‐Cl‐C catalyst exhibits distinguished ORR performance with a half‐wave potential (E1/2) of 0.92 V and excellent stability. Remarkably, the assembled Zn‐air battery based on Fe‐NP‐Cl‐C delivers an extremely high peak power density of 260 mW cm−2 and a large specific capacity of 812 mA h g−1, outperforming the commercial Pt/C and most reported congeneric catalysts. This study offers a new perspective on structural optimization and coordination engineering of single‐atom catalysts for efficient oxygen electrocatalysis and energy conversion devices. [ABSTRACT FROM AUTHOR]

High pressure is an effective means to optimize the thermoelectric (TE) performance by sharply improving the electrical properties of materials. Studying the carrier effective mass (m*) is a feasible way to uncover the basic reason for superior electrical properties under high pressure. However, it is still difficult to obtain the m* under pressure in experiments. Thus, in this work, the m* of α-PbSe (F m 3 ̄ m) under high pressure is calculated by band dispersion relation based on the density functional theory. It is found that the high pressure decreases m* of α-PbSe, which is the cause for excellent electrical properties. Moreover, the isotropy of m* enhances with the increase in the pressure, which means the high pressure further optimizes the isotropy of the carrier migration in the structure. It is reveled that the higher the pressure, the more beneficial to improve the electrical properties of α-PbSe, thus optimizing the TE performance before the phase transition pressure (4.5 GPa). This work is of great significance for exploring the mechanism of in situ high-pressure TE properties in the future, as well as the prediction and selection of high-performance TE materials under high pressure. [ABSTRACT FROM AUTHOR]

Ru-doped TiO 2 nanoribbon array supported on Ti plate acts as an efficient catalyst for NH 3 synthesis via electrochemical NO 2 − reduction, obtaining an ultra-large NH 3 yield of 1.56 mmol h−1 cm−2 and a super-high Faradaic efficiency of 98.9%. [Display omitted] • Ru doping is shown as an effective strategy to boost NO 2 −-to-NH 3 conversion over TiO 2 nanoribbon array supported on Ti plate. • Ru–TiO 2 /TP achieves an ultra-large NH 3 yield of 1.56 mmol h−1 cm−2 and a super-high Faradaic efficiency of 98.9% with long-term electrolytic durability. • DFT calculations reveal the catalytic mechanism of NO 2 –RR on Ru–TiO 2. Electrochemical reduction of nitrite (NO 2 –) not only removes NO 2 – contaminant but also produces high-added value ammonia (NH 3). This process, however, needs efficient and selective catalysts for NO 2 −-to-NH 3 conversion. In this study, Ruthenium doped titanium dioxide nanoribbon array supported on Ti plate (Ru–TiO 2 /TP) is proposed as an efficient electrocatalyst for the reduction of NO 2 − to NH 3. When operated in 0.1 M NaOH containing NO 2 –, such Ru–TiO 2 /TP achieves an ultra-large NH 3 yield of 1.56 mmol h−1 cm−2 and a super-high Faradaic efficiency of 98.9%, superior to its TiO 2 /TP counterpart (0.46 mmol h−1 cm−2, 74.1%). Furthermore, the reaction mechanism is studied by theoretical calculation. [ABSTRACT FROM AUTHOR]

Both graphene and hexagonal boron nitride (h‐BN) have found their application in catalysis and electronic devices owing to their unique π electronic nature. However, it remains unclear on how their sizes and growing modes influence their electronic properties. In order to extensively understand their structure–property relationship to stimulate and assist potential applications, in this work, the electronic structures of the polyaromatic hydrocarbons (PAHs) and polyborazines (boron nitride nanosheets, BNNSs) were analyzed by means of density functional theory calculations to investigate how the one‐ and two‐dimensional growth of their building blocks, benzene and borazine, respectively, may modulate/govern their aromaticity and reactivities. The analysis shows that the aromaticity and reactivity of PAHs exhibit significant response to their geometries, while the properties of BNNSs show strong localization nature and are nearly size‐independent. This unique nature of BNNSs is different from both the organic polyaromatic molecules and the inorganic metal/metal oxides whose reactivity may be significantly enhanced upon modulating their sizes, and offers implications in the design of new materials grafted by BNNS for manipulatable electronic properties. This study also brings caution on the application of widely used aromaticity descriptors, and shows that in general the descriptors derived from electronic structure are more reliable. [ABSTRACT FROM AUTHOR]

The coordination microenvironment of metal active sites in metal–organic frameworks (MOFs) plays a crucial role in its performance for electrochemical CO2 reduction reaction (CO2RR). However, it remains a challenge to clarify the structure–performance relationship for CO2RR catalyzed by MOFs. Herein, a series of MOFs with different coordination microenvironments of Cu(I) sites (CuCl, CuBr, and CuI) to evaluate their performances for CO2RR is synthesized. With the increasing radius of halogen atom, the CO2 adsorption capacity increases and d‐band center of Cu positively shifts to the Fermi level, leading to enhance the selectivity of CO2 to CH4 conversion. CuI gives the highest total Faradaic efficiency (FE) of 83.2%, with a FE of CH4 up to 57.2% and CH4 partial current density of 60.7 mA cm−2 at −1.08 V versus reversible hydrogen electrode. Theoretical calculations reveal that the shifted d‐band center of Cu site contributes to reduced formation energies of *CH2O and *CH3O intermediates, which is the potential‐determining step of CO2RR and thus facilitates the electrocatalytic CO2 reduction to CH4. This study opens a new avenue for studying the relationship between the coordination microenvironment of active site and electroreduction reaction performance of MOFs. [ABSTRACT FROM AUTHOR]

The coordination microenvironment of metal active sites in metal–organic frameworks (MOFs) plays a crucial role in its performance for electrochemical CO2 reduction reaction (CO2RR). However, it remains a challenge to clarify the structure–performance relationship for CO2RR catalyzed by MOFs. Herein, a series of MOFs with different coordination microenvironments of Cu(I) sites (CuCl, CuBr, and CuI) to evaluate their performances for CO2RR is synthesized. With the increasing radius of halogen atom, the CO2 adsorption capacity increases and d‐band center of Cu positively shifts to the Fermi level, leading to enhance the selectivity of CO2 to CH4 conversion. CuI gives the highest total Faradaic efficiency (FE) of 83.2%, with a FE of CH4 up to 57.2% and CH4 partial current density of 60.7 mA cm−2 at −1.08 V versus reversible hydrogen electrode. Theoretical calculations reveal that the shifted d‐band center of Cu site contributes to reduced formation energies of *CH2O and *CH3O intermediates, which is the potential‐determining step of CO2RR and thus facilitates the electrocatalytic CO2 reduction to CH4. This study opens a new avenue for studying the relationship between the coordination microenvironment of active site and electroreduction reaction performance of MOFs. [ABSTRACT FROM AUTHOR]

As a high-active metal-free electrocatalyst for NH 3 production via NO reduction reaction, honeycomb carbon nanofiber achieves an NH 3 yield of 22.35 μmol h−1 cm−2 with a high Faradaic efficiency of 88.33%. [Display omitted] Electrocatalytic NO reduction is a promising technology for ambient NO removal with simultaneous production of highly value-added NH 3. Herein, we report that honeycomb carbon nanofiber coated on carbon paper acts as an efficient metal-free catalyst for ambient electroreduction of NO to NH 3. In 0.2 M Na 2 SO 4 solution, such catalyst achieves an NH 3 yield of 22.35 μmol h−1 cm−2 with a high Faradaic efficiency of up to 88.33%. Impressively, it also shows excellent stability for 10-h continuous electrolysis. Theoretical calculations reveal that the most active center of functional groups is –OH group for NO reduction with a low energy barrier (ΔG of 0.29 eV) for the potential-determining step (*NO + H → *HNO). [ABSTRACT FROM AUTHOR]

Sustainable mitigation of the continuously rising concentration of NO contaminants is among the most urgent issues of this century. Ambient electrocatalytic conversion of NO into useful NH3 offers an attractive path toward achieving sustainable NO abatement and NH3 production simultaneously. However, its efficiency is challenged by the intense competition from hydrogen evolution reaction and relatively high energy barriers of NO activation. It is thus highly desirable to explore active electrocatalyst for NO reduction reaction and investigate the mechanisms on relevant surfaces. Herein, we introduce an FeP nanorod array on carbon cloth as a high-efficiency catalyst for NO electroreduction to NH3. In 0.2 M phosphate-buffered solution, this catalyst exhibits a low onset potential of −0.014 V. Moreover, it achieves a remarkable Faradaic efficiency of 88.49% and a large NH3 yield of 85.62 µmol·h−1·cm−2, with durability for stable NO conversion over 12 h of electrolysis. The catalytic mechanism on FeP is investigated further by theoretical calculations. [ABSTRACT FROM AUTHOR]

Purposefully developing crystalline materials at molecular level to improve the selectivity of electroreduction CO2 to CH4 is still rarely studied. Herein, a single crystal of copper(II) complex with hydroxy groups was designed and synthesized, namely 5,10,15,20‐tetrakis(3,4‐dihydroxyphenyl)porphyrin copper(II) (Cu‐PorOH), which could serve as a highly efficient heterogeneous electrocatalyst for electroreduction of CO2 toward CH4. In 0.5 m KHCO3, Cu‐PorOH gave a high faradaic efficiency of 51.3 % for CH4 and drove a partial current density of 23.2 mA cm−2 at −1.5 V versus the reversible hydrogen electrode in H‐cell. The high performance was greatly promoted by the hydroxy groups in Cu‐PorOH, which could not only form stable three‐dimensional frameworks through hydrogen‐bonding interactions but also stabilize the intermediate species by hydrogen bonds, as supported by density functional theory calculations. This work provides an effective avenue in exploring crystalline catalysts for CO2 reduction at molecular level. [ABSTRACT FROM AUTHOR]

The non-equivalent doping of Mn4+ in red-emitting fluoride phosphors effectively shortens the fluorescence lifetime. Herein, we successfully synthesized Rb2NaInF6:Mn4+ phosphors by an ion-exchange method. The compensation mechanism of Mn4+ local symmetry and charge balance in the phosphor were studied in detail by theoretical calculations based on density functional theory. The phosphor Rb2NaInF6:Mn4+ (5.59 mol%) exhibits intense red emission with a short fluorescence lifetime (1.45 ms). Meanwhile, it has excellent colour stability and thermal quenching stability at elevated temperatures. Using Rb2NaInF6:Mn4+, β-SiAlON:Eu2+ and a blue-emitting GaN chip as red, green, and blue components, the white light-emitting diode (w-LED) exhibits a wide colour gamut of 94.1% of the National Television System Committee (NTSC) standard value. So, this work provides valuable information to investigate novel red-emitting fluoride phosphors for LED backlighting. [ABSTRACT FROM AUTHOR]

Ammonium iodine (NH4I) as an important member of hydrogen-rich compounds has attracted a great deal of attention owing to its interesting structural changes triggered by the relative orientations of adjacent ammonium ions. Previous studies of ammonium iodide have remained in the low pressure range experimentally, which we first extended to so high pressure (250 GPa). We have investigated the structures of ammonium iodine under high pressure through ab initio evolutionary algorithm and total energy calculations based on density functional theory. The static enthalpy calculations show that phase V is stable until 85 GPa where a new phase Ibam is identified. Calculations of phonon spectra show that the Ibam phase is stable between 85 GPa and 101 GPa and the Cm phase is stable up to 130 GPa. In addition, ammonium iodine dissociates into NH3, H2, and I2 at 74 GPa. Subsequently, we analyzed phonon spectra and electronic band structures, finding that phonon softening is not the reason of dissociation and NH4I is always a semiconductor within the pressure range. [ABSTRACT FROM AUTHOR]

It is of great importance to search for efficient and stable metal-free catalysts toward electrochemical N2-to-NH3 conversion. In this communication, a chemically oxidized carbon nanotube material (O-CNT) is verified as an active electrocatalyst for the N2 reduction reaction under ambient conditions. In 0.1 M LiClO4, O-CNT achieves a large NH3 yield of 32.33 μg h−1 mgcat.−1 and a high faradaic efficiency of 12.50% at −0.4 V vs. the reversible hydrogen electrode. It also demonstrates superior stability. Density functional theory calculations suggest that C–O groups play a key role in the electrochemical N2 fixation. [ABSTRACT FROM AUTHOR]

• The removal mechanism of O-containing functional groups were studied. • Effect of O-containing groups on floatibility characteristics was studied. • The ESP, bond order, and BDE of lignite molecular structure were calculated by DFT. • The essential reason for decrease of water content during HTD was explained. Hydrothermal treatment dewatering (HTD) is a potential means for efficiently and cleanly utilizing lignite due to its comprehensive modification, including dehydration and deoxidation.These processes are as tightly linked to the removal of O-containing functional groups in lignite. However, the O removal mechanism during the HTD process is not clear. It is important to deeply study this problem for the efficient application of upgraded lignite. Herein, density functional theory (DFT) simulations combined with experiments have been carried out to investigate the removal mechanism of O-containing functional groups. In addition, the HTD influence on the flotation characteristics was studied. The results showed that the carbon content and the calorific value increase after the HTD process, which improve the lignite quality. The oxygen content decreased from 28.55 to 16.67%, and the O/C atomic ratio decreased from 0.33 to 0.16 at 310 °C. The FT-IR results showed that the decrease in oxygen content is due to the cleavage and decomposition of methoxy, alcohol hydroxyl, and carboxyl groups. These results are consistent with the DFT results of bond orders and bond dissociation energies (BDE). The BDE order in the HTD process is: C O in methoxy < C O in alcohol hydroxyl < C C attached to carboxyl and carbonyl < C O in phenoxy ether < C O in phenolic hydroxyl < C O in carboxyl and carbonyl. The most stable chemical bonds are C O in carboxyl and carbonyl where the BDE values are over 550 kJ/mol. The large absolute electrostatic potential values are found to be around the O-containing functional groups. These O-containing functional groups very easily form hydrogen bonds with water, which results in stronger hydrophilicity and high-water content. Therefore, the removal of O-containing functional groups changes the surface characteristics. Besides, the contact angle of the upgraded lignite increases while the wettability decreases. Thus, the flotation characteristics of the upgraded lignite are significantly improved. [ABSTRACT FROM AUTHOR]

[Display omitted] • A strategy to design metal-free catalyst for nitric oxide reduction is developed. • Molecular orbital theory and band theory are combined to study catalytic mechanism. • A particular C center -CN 2 active site on hBN-graphene interface is discovered. • The high-activity C center -CN 2 configuration is applicable to other 2D materials. Electrochemical reduction reaction of nitric oxide (NORR) to ammonia has been considered as a promising alternative to capturing and utilizing NO emitted from thermal-power plants. Various metal-containing catalysts have been proved to possess efficient catalytic activities for NORR, yet the attempt on metal-free NORR catalysts is quite limited. Herein, by employing first-principle calculations, we propose a novel strategy of designing metal-free NORR catalyst by introducing C center -CN 2 configuration into hexagonal boron nitride-graphene heterostructures (hBN-graphene). The hBN-graphene heterostructures demonstrate excellent NORR activity, achieving a fairly low limiting potential of −0.22 V. The superior NORR activity is ascribed to the introduced unique configuration at the modified hBN-graphene interface. Moreover, the hBN-graphene heterostructures can efficiently suppress hydrogen evolution—the main competitive reaction. The ab-initio molecular dynamic simulations indicate that hBN-graphene heterostructures can retain considerable thermal stability. Our work opens an avenue to design metal-free catalysts for NORR by modulating the interface in two-dimensional heterostructures. [ABSTRACT FROM AUTHOR]

Harvesting water and energy from ambient environment promises to relieve the worldwide fresh-water scarcity and energy shortage. The fabrication of well-designed materials for atmospheric water harvesting (AWH) requires highly-technical skills, hampering practical applications in isolated regions or after natural disasters. Herein, we report an efficient moisture absorber from waste corn stalk for AWH and for concurrent electricity generation. The sample can adsorb water at capacities of 0.46–1.84 kg kg−1 under relative humidity of 20%–80%. Moreover, with surface modification using commercial carbon ink, a corn stalk slice (3 cm × 1 cm × 0.2 cm) can output a stable open-circuit voltage of ~0.6 V in the air. Density functional theory calculations reveal that the oxygen groups in the carbon ink contribute to the power generation in the corn stalk. When connected in series, corn stalk slices can directly power an electronic calculator. This study contributes to the development of practical strategies to address issues in the water-waste-energy nexus. Image 1 • Waste corn stalk based moisture absorber was developed for atmospheric water harvesting and electricity generation. • The moisture absorber delivered water harvesting capacities of 0.46–1.84 kg kg−1 under relative humidity of 20%–80%. • The corn stalk with size of 3 cm × 1 cm × 0.2 cm generated a stable voltage of ~0.6 V for over 40 h in the air. • 3 corn stalks connected in series could power an electronic calculator in the atmosphere. [ABSTRACT FROM AUTHOR]

Biomimetic design is achieved to synthesize FeOOH@CNTs composite with ultrathin edge-riched FeOOH "leaves" supported by CNT "branches" as OER catalyst. The "leaf-branch" structural FeOOH@CNTs catalyst exhibits superior catalytic activity to commercial RuO 2. • Biomimetic design of FeOOH@CNTs with ultrathin FeOOH "leaves" on carbon nanotube "branches". • The "leaf-branch" structural FeOOH@@CNTs exposes much more catalytic active sites for OER. • The synergistic effect of FeOOH "leaves" and CNT "branches" reduced the energy barrier for OER. • The FeOOH@@CNTs exhibits yet the best catalytic performances for overall water splitting. Based on a plant-like morphology, here, we report a multidimensional composite with ultrathin edge-riched FeOOH "leaves" growing on carbon nanotube "branches" (FeOOH@CNTs) via a facile and environmentally benign approach. A Fenton reaction was adopted to oxidize carbon nanotubes (CNTs), and FeOOH flakes were generated on the CNTs as reaction proceeded. The highly conductive CNT "branches" ensure rapid electron transmission and compensate for low conductivity of the FeOOH "leaves". Meanwhile, ultrathin FeOOH "leaves" growing on CNT "branches" expose sufficient numbers of active sites for oxygen evolution reaction (OER). Density functional theory (DFT) computational results indicate that FeOOH@CNTs exhibit better OER catalytic performance than FeOOH. To achieve water splitting, FeOOH@CNTs were deposited on nickel foam as an anode, with platinum (Pt) sheet used as a cathode. A low cell voltage of only 1.44 V was achieved to yield a current density of 10 mA cm–2 with a TOF of 12.50 s-1. [ABSTRACT FROM AUTHOR]

[Display omitted] • A Mn/Cu co-doping mesoporous carbon was synthesized via template method for mercury removal. • The MnCu 0.1 -C sorbent displayed high mercury removal performance with main product of HgO. • Mn doping on the mesoporous carbon greatly improved the mercury removal ability of sorbent. • Cu doping improved the SO 2 tolerance of sorbent due to a larger affinity of Cu to sulfur. • DFT analysis displayed that Hg0 was mainly chemisorbed on the surface of MnCu 0.1 -C sorbent. Mn/Cu co-doping mesoporous carbon sorbent (MnCu x -C) was synthesized via using hard template method. Thymol blue (C 27 H 30 O 5 S) was used as carbon source and MCM-41 was applied as template agent. Copper nitrate trihydrate (Cu(NO 3) 2 ·3H 2 O) and manganese acetate tetrahydrate (MnC 4 H 6 O 4 ·4H 2 O) was in-situ co-doped with carbon source as Cu/Mn metals precursor. Mercury removal on the MnCu x -C sorbent was investigated on a fixed bed experimental apparatus. The physical and chemical characteristics of the MnCu x -C sorbent were investigated by using BET, SEM, FTIR, XRD and XPS, respectively. Combing with mercury programmed temperature desorption (Hg-TPD) and density functional theory (DFT), the mechanism of mercury adsorption on the MnCu x -C sorbent was revealed. The results showed that the synthesized MnCu 0.1 -C sorbent displayed high mercury removal performance at 150℃, which was considered to be a potential sorbent for mercury removal from industrial flue gas. Mn doping on the mesoporous carbon greatly improved the mercury removal ability of sorbent with mercury capture rate increasing from 6 % to 89 %. Doping of Cu can effectively improve the SO 2 tolerance of the MnCu 0.1 -C sorbent for mercury removal. With different concentration of SO 2 existing in flue gas, the MnCu 0.1 -C sorbent still kept high mercury removal ability. O 2 in flue gas promoted mercury removal on the MnCu 0.1 -C sorbent with main product of HgO. In the presence of SO 2 , a small amount of HgSO 4 formed on the MnCu 0.1 -C sorbent. The DFT analysis further displayed that Hg0 was mainly chemisorbed on the surface of MnCu 0.1 -C sorbent with formation of HgO. [ABSTRACT FROM AUTHOR]

The ternary Li-Al-Te compounds were investigated by the first-principle evolutionary calculation based on density function theory. Apart from the known structure, I -42 d LiAlTe 2 and P 3 m 1 LiAlTe 2 , several new structures were discovered, P -3 m 1 LiAlTe 2 , Pnma LiAlTe 2 , C 2/ c Li 9 AlTe 2 , Immm Li 9 AlTe 2 and P 4/ mmm Li 6 AlTe. We determined that the I -42 d LiAlTe 2 firstly changed to P -3 m 1 phase at 6 GPa, and then into the Pnma structure at 65 GPa, Pnma phase was stable up at least to 120 GPa. I -42 d LiAlTe 2 was a pseudo-direct band gap semiconductor, but P -3 m 1 LiAlT 2 was an indirect band gap semiconductor. This may be caused by the pressure effect. Subsequently, it was metallized under pressure. Pnma LiAlTe 2 was also metallic at the pressure we studied. C 2/ c Li 9 AlTe 2 was stable above 4 GPa, then turned into Immm phase at 60 GPa. C 2/ c Li 9 AlTe 2 was an indirect band gap semiconductor. The results show that P 4/ mmm Li 6 AlTe was stable and metallized in the pressure range of 0.7–120 GPa. The calculations of DOS and PDOS indicate that the arrangement of electrons near Fermi energy can be affected by the increase of Li. The calculated ELF results and Bader charge analysis indicate that there was no covalent bond between Al and Te atoms for high-pressure Pnma LiAlTe 2 , Li 9 AlTe 2 and Li 6 AlTe. For Li 9 AlTe 2 and Li 6 AlTe, different from LiAlTe 2 , Al atoms not connect with Te atoms, but link with Li atoms. The results were further proved by Mulliken population analysis. And the weak covalent bonds between Li and Al atoms stem from the hybridization of Li s and Al p presented in PDOS diagrams. We further deduced that the pressure effect and the increase of Li content may result in the disappearance of Al-Te bonds for Li-Al-Te compound under extreme pressure. [ABSTRACT FROM AUTHOR]

• 112TCE and NaOH reaction kinetics was studied by simulation and experiment. • The conductometry and substrate concentration amplification method were first used. • The kinetic parameters of three parallel reactions were decoupled. • Kinetic parameters of overall and parallel reactions were obtained. Dehydrochlorination of 1,1,2-trichloroethane (112TCE) is a widely used method for preparing vinylidene chloride (VDC), which is an important polymeric monomer and intermediate of refrigerant. However, there are few reports on kinetics of this reaction system. In this work, density functional theory (DFT) calculation analyses and experiments were conducted to investigate the reaction mechanism and kinetics of 112TCE dehydrochlorination with sodium hydroxide (NaOH). DFT simulation results unveiled there were three parallel reactions which produce VDC, cis -1,2-dichloroethylene (C12DE) and trans -1,2-dichloroethylene (T12DE) respectively in the reaction process of 112TCE and NaOH. The activation energy of the reaction to produce VDC was lower than those of the other two reactions. Moreover, the kinetic parameters of the three parallel reactions, such as reaction orders, rate constants, pre-exponential factors and activation energies, were experimentally obtained by decoupling the overall reaction kinetics. All the parallel reactions are bimolecular elimination reactions and the rate expression of the intrinsic kinetics for generating VDC is d C t dt = 1.668 × 10 11 e - 75662 RT C A C B. The reaction rate is three orders of magnitude higher than those of producing C12DE and T12DE, which is consistent with the DFT simulation results. These kinetics results are useful for the process optimization and reactor design in VDC production process. [ABSTRACT FROM AUTHOR]

• Cs 2 KGaF 6 :Mn4+ phosphor with high EQE of 43% was systhesized via co-participated methods. • DFT calculation reveals [MnF 6 ]2- occupied [GaF 6 ]3- and produce a V Cs ′ vacancy to balance the charge mismatch. • Unequivalent doping strategy provides detailed insights into the local structure of Mn4+ substituted in fluorides. • Cs 2 KGaF 6 :Mn4+ phosphor is suitable for wide color gamut displays. [Display omitted] Narrow-band red-emitting phosphors are worth investigating and developing to enhance their luminescence efficiency for white light-emitting diodes (WLEDs) and broaden the color gamut of backlight displays. Herein, a novel red-emitting fluoride phosphor Cs 2 KGaF 6 :Mn4+ (CKGFM) was synthesized, which presents sharp red emission bands, short fluorescence lifetime (τ = 3.81 ms) and high external quantum efficiency (EQE = 43%). To better understand Mn4+ incorporation in CKGFM, density functional theory (DFT) energetic calculations were performed to compare the charge compensation probabilities of an Mn4+ substituted at a Ga3+ or K+ site. The temperature-dependent luminescence trend shows that the CKGFM phosphor has good thermal stability in the temperature range of 15–120 ℃, indicating its potential in backlight LEDs. The as-prepared CKGFM phosphor was used to fabricate one white light-emitting diode (WLED) with β-SiAlON:Eu2+ green phosphor and blue InGaN LED chip, which shows a high luminous efficiency of 106.30 lm∙W−1 and a National Television Standards Committee (NTSC) value of 114.6%. The present study provides detailed insights into the local structure of Mn4+ substituted in fluoride red-emitting phosphors and helps to realize better Mn4+ emission for WLEDs. [ABSTRACT FROM AUTHOR]