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Earth-abundant Fe oxide-based catalysts, renowned for their broad-spectrum light absorption, hold promise for driving the photothermal RWGS reaction—a promising strategy for converting CO 2 emissions into valuable carbonaceous feedstocks. However, traditional Fe oxide-based catalysts exhibit limited activity due to their constrained H 2 dissociation and CO 2 activation capabilities, especially at lower temperatures. This study introduces Co, Ni, and Cu-doped Ce 0.7 Fe 0.3 O 2 solid-solution catalysts. Incorporation of Fe into CeO 2 enhances CO 2 dissociation while preserving extensive light adsorption up to 2500 ​nm. Notably, Co doping enhances H 2 dissociation and promotes CO 2 activation. Subsequent investigations reveal that a catalyst doped with 5 ​mol% Co exhibits the highest photothermal catalytic activity, attaining a ∼50 ​% CO 2 conversion under 300 ​W Xe-lamp irradiation with excellent selectivity and stability over 10 reaction cycles spanning 10 ​h. These results underscore the potential of designing CeO 2 -based solid solution catalysts with synergistic metal dopants for efficient and selective CO 2 conversion under moderate conditions. [ABSTRACT FROM AUTHOR]

Mesoporous cobalt- and/or iron-substituted aluminophosphates were synthesized by a hydrothermal method, followed by pyrolysis and calcination. The substitution of the transition metal elements modified the electronic properties of the samples and the accompanying surface characteristics. The samples showed tunable catalytic activity through the substitution of Fe and/or Co. We have demonstrated that the light-induced photocatalytic 4-nitrophenol reduction reaction can be enhanced through the substitution of Fe and/or Co in aluminophosphates. The induction time associated with the three different types of samples, observed due to the influence of the substituents, allows us to understand the mechanism of the 4-nitrophenol reduction process in our samples. Our work solves the issue associated with the origin of induction time and the enhancement of the catalytic activity of mesoporous aluminophosphates in the 4-nitrophenol reduction reaction through a controlled modification of the electronic properties. [ABSTRACT FROM AUTHOR]

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The photocatalyst NaTaO3, owing to its notable chemical and thermal stability as well as environmental friendliness, emerges as a versatile candidate capable of meeting diverse demands across various fields. Through ion doping, it is feasible to modulate the electronic structure and performance of NaTaO3. In this study, employing density functional theory (DFT), electronic structure and optical properties of perovskite-type Na0. 75 B0. 25 TaO3 (where B = Cr, Mn, Fe, Cu, Zn) were systematically investigated, elucidating the impact of different transition metal dopants on the band structure and electron density of states in NaTaO3. The investigation reveals that Cr, Mn, Fe, and Zn doping induces metallic properties, while Na0.75 Cu0.25 TaO3 exhibits semiconductor characteristics, accompanied by a narrowed bandgap of 1. 35 eV. The introduction of Cu introduces new energy levels (Cu 3d and Cu 4s) within the bandgap, positioned at its center, resulting in an upward shift of the valence band. Furthermore, the absorption spectra in the Cu-doped system exhibit a redshift, extending the light absorption wavelength up to 800 nm. Subsequently, the photocatalytic antibacterial performance of NaTaO3 and Na0.75 Cu0.25 TaO3 was explored, demonstrating a bactericidal efficiency of 99. 99% against Staphylococcus aureus (S. aureus) following Cu ion modulation. Finally, an analysis of potential antibacterial mechanisms was undertaken. [ABSTRACT FROM AUTHOR]

The magnetic, electronic, and optical properties of transition metal X (X = Cr, Mn, Fe, Tc, Re) atomically doped Janus Ga2SSe are investigated using the first-principles plane-wave method based on the density functional theory. It's shown that the transition metal-doped Janus Ga2SSesystems have better stability under Chalcogen-rich condition than under Ga-rich condition. The Mn-doped system has the lowest formation energy under both conditions. The intrinsic Ga2SSe is an indirect bandgap semiconductor with a bandgap of 2. 02 eV and has good photovoltaic absorption in the ultraviolet (UV) region. Compared with the intrinsic Ga2SSe, the impurity energy levels appear in the spin-up channel of the Cr-doped system, which makes the spin-up and spin-down channels asymmetric, and presents the ferromagnetic semimetal property with a magnetic moment of 2.797μB. The impurity energy levels appear in the spin-up channel of the Mn-doped system, making the system become a magnetic P-type semiconductor with a magnetic moment of 3. 645μB. The impurity energy level appears in the spin-down channel of the Fe-doped system, making the system become a magnetic P-type semiconductor with a magnetic moment of 3. 748μB magnetic. After doping of Te and Re, the band gaps are changed from indirect to direct band gaps, and both systems are non-magnetic P-type semiconductors. In terms of optical properties, each doped system has significantly enhanced dielectric constant and refractive coefficient compared with undoped Ga2SSe, and the absorption coefficient appears blue-shifted in the high energy region (3-10 eV). It has potential applications in the field of UV detectors and photovoltaic absorption. [ABSTRACT FROM AUTHOR]

In this study, the Cr2+ :CdSe and Fe2+ :CdSe crystals were successfully grown by the Mo-crucible sealed Bridgman method using a vacuum single-crystal furnace with two zones developed by ourselves, and the crystal size reaches φ51 mm x 110 mm. Cr2+ :CdSe and Fe2+ :CdSe crystals demonstrate obvious absorption in the bands of 1 400 ~ 2 400 nm and 2 500 ~5 200 nm, respectively. The transmittances of Cr2+/Fe2+ doped CdSe crystals are close to the transmittance limit of CdSe crystal (~70%) in the 7 ~ 15 μm band, and the converted absorption coefficient is about 0.005 cm-1. The Cr2+/Fe2+ : CdSe crystals grown by the Mo-crucible sealed Bridgman method have the advantages of the controllable doping concentration of transition metal ions, uniform doping and high crystal quality. The Cr2+/Fe2+ : CdSe crystals could be used as both midinfrared laser crystal and far-infrared nonlinear optical crystal material. [ABSTRACT FROM AUTHOR]

Mesoporous cobalt- and/or iron-substituted aluminophosphates were synthesized by a hydrothermal method, followed by pyrolysis and calcination. The substitution of the transition metal elements modified the electronic properties of the samples and the accompanying surface characteristics. The samples showed tunable catalytic activity through the substitution of Fe and/or Co. We have demonstrated that the light-induced photocatalytic 4-nitrophenol reduction reaction can be enhanced through the substitution of Fe and/or Co in aluminophosphates. The induction time associated with the three different types of samples, observed due to the influence of the substituents, allows us to understand the mechanism of the 4-nitrophenol reduction process in our samples. Our work solves the issue associated with the origin of induction time and the enhancement of the catalytic activity of mesoporous aluminophosphates in the 4-nitrophenol reduction reaction through a controlled modification of the electronic properties.

Emergence of inorganic metal halide perovskites as multifunctional optoelectronic materials are due to their exceptional tunability in optoelectronic properties. This study sought to enhance the physical and mechanical properties of lead-free FrGeI3 perovskites by introducing transition metal dopants (Mn, Co, and Ni). First-principle calculations based density functional theory (DFT) have been utilized to illustrate the impact of transition-metal doping on the structural, electronic, and light-matter interaction properties of FrGeI3. The study found that transition metal doping in FrGeI3 perovskites leads to an increase in the electronic bandgap leading to semiconducting behavior after phase stability confirmation. This study provides a sound understanding of the underlying mechanisms of transition metal doping in Fr-contained halide perovskites, which could pave the way to the headway of new optoelectronic and biomedical devices based on these materials.

Searching for stable, highly effective and cost‐efficient catalysts for the oxygen reduction reaction (ORR) is important to addressing the energy crisis and environmental issues. A single atom embedded in two‐dimensional boron nitride materials is a viable candidate for the ORR to replace Pt‐based catalysts. Herein, by making use of density functional theory (DFT) simulations, we systematically study a novel two‐dimensional boron nitride materials (bi‐BN) embedded by 23 kinds of transition metal (TM) atoms ranging from Ti to Au as high activity single atom electrocatalyst for the ORR. According to the initial screening criteria (−4.92 eV < ΔGO* < 0 eV), 13 kinds of TM‐bi‐BN (TM = Ti, V, Cr, Mn, Fe, Co, Ni, Ru, Rh, Pd, Ag, Pt, Au) meet the criteria and are selected to study their ORR performance in this work. Our calculations indicate that Au‐bi‐BN has the most superior ORR performance with the lowest overpotential (0.43 V), which was lower than that of Pt (0.45 V) as ORR catalyst. The origin of the catalytic activity of the ORR is studied by the linear correlation between these oxygen‐containing intermediates, the volcanic curve, the d‐band center and the crystal orbital Hamilton populations. Ab Initio Molecular Dynamics simulation suggests that Au‐bi‐BN is thermodynamically stable at 300 K. Our results not only offer valuable insights into the utility of boron‐nitride materials as catalysts for ORR, but also facilitate the development of novel catalysts for ORR through improved comprehension of the material properties. [ABSTRACT FROM AUTHOR]

The demand for lithium is constantly increasing due to its wide range of uses in an excessive number of industrial applications. Typically, expensive lithium-based chemicals (LiOH, LiCl, LiNO3, etc.) have been used to fabricate adsorbents (i.e., lithium manganese oxide) for lithium ion (Li+) adsorption from aqueous sources. This type of lithium-based adsorbent does not seem to be very effective in recovering Li+ from water from an economic point of view. In this study, an innovative nanocomposite for Li+ adsorption was investigated for the first time, which eliminates the use of lithium-based chemicals for preparation. Here, calcium oxide nanoparticles (CaO-NPs), silver-doped CaO nanoparticles (Ag-CaO-NPs), and surfactant (polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS))-modified Ag-CaO (PVP@Ag-CaO and SDS@Ag-CaO) nanocomposites were designed by the chemical co-precipitation method. The PVP and SDS surfactants acted as stabilizing and capping agents to enhance the Li+ adsorption and recovery performance. The physicochemical properties of the designed samples (morphology, size, surface functionality, and crystallinity) were also investigated. Under optimized pH (10), contact time (8 h), and initial Li+ concentration (2 mg L−1), the highest Li+ adsorption efficiencies recorded by SDS@Ag-CaO and PVP@Ag-CaO were 3.28 mg/g and 2.99 mg/g, respectively. The nature of the Li+ adsorption process was examined by non-linear kinetic and isothermal studies, which revealed that the experimental data were best fit by the pseudo-first-order and Langmuir models. Furthermore, it was observed that the SDS@Ag-CaO nanocomposite exhibited the highest Li+ recovery potential (91%) compared to PVP@Ag-CaO (85%), Ag-CaO NPs (61%), and CaO NPs (43%), which demonstrates their regeneration potential. Therefore, this type of innovative adsorbents can provide new insights for the development of surfactant-capped nanocomposites for enhanced Li+ metal recovery from wastewater. [ABSTRACT FROM AUTHOR]

Bending strain sensors based on one-dimensional ZnO nanorod (NR) arrays cross-linked with interdigitated electrodes were fabricated on polyethylene terephthalate (PET) substrates. ZnO NRs were grown using the hydrothermal method through the dopings with different transition metals, such as Co, Ni, or Co-plus-Ni, on PET substrates, and their microstructural morphology and crystalline properties were examined by a variety of surface analysis methods. Ultraviolet photoresponse and normalized resistance change were measured according to the bending strains to concave and convex directions, and the highest gauge factors of 175 and 83 were achieved in the convex and concave directions, respectively, at a bending strain of 1.75%, when Co-plus-Ni was doped to the NRs. [ABSTRACT FROM AUTHOR]

[Display omitted] • On VO 2 /CeO 2 (1 1 1) propene formation over 81% of active sites. • Vanadia monomers and dimers active but less selective for propene. • Higher vanadia oligomers improve propene selectivity but lower activity. • Ni doped ceria improves VO x stability and modulate activity of bridged O. • Ni doping of ceria enhances propene selectivity across vanadia oligomers. Propane oxidative dehydrogenation (ODH) was studied over VO x /CeO 2 nanoparticle catalysts for various vanadia nuclearities using Density Functional Theory simulations. On monomers and dimers, propene formation involved V=O, bridged (V–O–Ce, V–OV) and ceria surface oxygens but with low selectivity, while on trimers and possibly higher oligomers it was kinetically favourable over ceria surface oxygens, with higher selectivity than on monomers and dimers. On trimer, overoxidation via acetone formation was inhibited, but at the expense of overall catalyst reactivity. Doping of ceria support with Ni induced strong Ni–VO x interactions, stabilizing the vanadia monomer. The V–O–Ni bridged oxygen was less accessible for overoxidation, resulting in an increase in activation energy barrier for acetone formation by 0.69 eV on VO 2 /Ce 0.89 Ni 0.11 O 2 (1 1 1), while there was a minimal impact on V 3 O 6 /Ce 0.89 Ni 0.11 O 2 (1 1 1). Hence, transition metal doping of ceria support is a potential strategy to improve propene selectivity over VO x /CeO 2 catalysts for a wide range of V loadings. [ABSTRACT FROM AUTHOR]

Magnetisms, band structures and optical properties of two - dimensional single layer β - GeS by alter- native doping different 3d transition metal atoms are systematically studied by first - principles calculations. The results show that substitution doping with Ti - Cu can lead the non - magnetic β - GeS to exhibit magnetic behavior, and the magnetic moment increases first and then decreases. The band structure of the doped system changes obviously, embodying the attributes of metal, semimetal and semiconductor, in addition, the energy band of the conduction band obviously moves to the valence band. The extrinsic systems have a blue shift in a certain wave- length range and the light response intensity changes, and the system also shows high anisotropy before and after doping. [ABSTRACT FROM AUTHOR]

Feasibility of activating the basal planes of a ternary tri-chalcogenide material MnPSe 3 towards hydrogen evolution reaction (HER) by internal regulation of substitutional doping is studied using first-principles electronic structure calculations. A fraction of the Mn atoms is replaced by a first– or second–row transition metal atom. While the basal plane of the pristine material is inactive to HER with the change in H adsorption free energy (Δ G H ∗) of 1.41 eV, some dopants significantly improve the activity of the planes as deduced from the calculated Δ G H ∗ value. Whether such substitutional doping is energetically favored is checked by calculating the formation energy of each of the materials. Activity enhancement at different concentrations of the dopants is also tested. We find that three elements, Sc, Y, and Mo, out of a total of 19, activate the basal planes with Δ G H ∗ values of 0.24, 0.18, and 0.23 eV, respectively, raising the possibility of increasing the efficiency of MnPSe 3 as an HER catalyst. We also find an interesting correlation between the electronic densities of states of material and the calculated Δ G H ∗ values. [Display omitted] • TM-doped MnPSe 3 monolayers are thermodynamically more stable than isolated elemental phases of the constituents. • Substitutional TM-doping significantly improves the HER activity of the basal plane of MnPSe 3. • An interesting correlation was found between DOS and HER activity of the basal plane. [ABSTRACT FROM AUTHOR]

Crystalline transition-metal chalcogenides are the focus of solid state research. At the same time, very little is known about amorphous chalcogenides doped with transition metals. To close this gap, we have studied, using first principle simulations, the effect of doping the typical chalcogenide glass As2S3 with transition metals (Mo, W and V). While the undoped glass is a semiconductor with a density functional theory gap of about 1 eV, doping results in the formation of a finite density of states (semiconductor-to-metal transformation) at the Fermi level accompanied by an appearance of magnetic properties, the magnetic character depending on the nature of the dopant. Whilst the magnetic response is mainly associated with d-orbitals of the transition metal dopants, partial densities of spin-up and spin-down states associated with arsenic and sulphur also become slightly asymmetric. Our results demonstrate that chalcogenide glasses doped with transition metals may become a technologically important material. [ABSTRACT FROM AUTHOR]

The presence of various hazardous toxins such as Phenols, phthalates, pesticides, dyes, heavy metals, pharmaceutical waste, etc, is continuously increasing into the water bodies from different agricultural, industrial and domestic practices, which have brought the toxicity level to an alarming height. Often, these toxic compounds are quite stable in nature and the removal or degradation of these compounds is quite challenging, which further poses a significant threat to the environment. When it comes to enhance the efficiency of water purification and decontamination process, SnO2 nanoparticles offer great potential owing to their low concentration and large surface area. Over the past few years, SnO2 nanoparticles as a photocatalyst has garnered huge interest from the researcher community towards the photo-degradation of toxic pollutants present in the water bodies. Among various metal oxides, particularly SnO2 has been emerged as the most versatile material for doping of different transition metals due to its plethora of applications such as photocatalysis, energy harnessing, sensors, solar cells and optoelectronic devices. The pure and doped SnO2 has prominent significance due to its phenomenal catalytic and physicochemical properties such as chemically stable, inexpensive and non-toxic. This review explores and summarizes the progress of first and second transition metal series doping in SnO2 for its coherent application towards the degradation of water pollutants. We have emphasized the effect of different transition metal dopants used in the growth of SnO2 nanoparticles on the basis of their synthesis technique, source of irradiation used, nature of contaminations removed and obtained photodegradation efficiency.

• Enhanced photo-electrocatalytic CO 2 conversion using Fe, Co, and Ni-doped TiO 2 nanoparticles. • Synthesis via sol–gel process, followed by electrode coating with Nafion slurry. • Superior performance observed for Fe-doped TiO 2 in electrochemical CO 2 conversion efficiencies. The Fe, Co, and Ni-doped TiO 2 were synthesised by sol–gel process, and the nanomaterials were coated on electrodes through a slurry with Nafion. This study aims to use prepared nanoparticles of Fe, Co, and Ni-doped TiO 2 to enhance the photo-electrocatalytic conversion of CO 2. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and electrochemical analyses were utilized to characterise the doped and undoped TiO 2 nanoparticles. Transmission electron microscopy (TEM) studies revealed that the nanomaterials had an average size below 20 nm. Tauc plot analysis for optical absorption studies shown a reduction in band gap when doped with Fe, Co and Ni, with the most significant decrease observed for Fe-doped TiO 2 , following the order Fe < Co < Ni. Electrochemical CO 2 conversion efficiencies were investigated through cyclic voltammetry (CV) curves, electrochemical impedance spectroscopy (ESI), and linear sweep voltammetry (LSV) studies. The results were analysed based on various scan rates and photo exposure, indicating superior performance for Fe-TiO 2 , aligning with the observed band gap trends. Gas chromatography (GC) analysis of the reduction products revealed the generation of hydrocarbons, with Fe-TiO 2 exhibiting the most favourable outcomes. This research provides valuable insights into tailoring TiO 2 nanoparticles for efficient photo-electro catalytic reduction of CO 2. [ABSTRACT FROM AUTHOR]

• Pure undoped and transition metal doped CuO NPs were successfully synthesized by the co-precipitation method. • The doping of CuO NPs modulates the photocatalytic efficiency, depending on the extrinsic dopants Zn, Ni, Mn, Fe or Co. • T The logarithmic derivative approach is used for precisely estimate the bandgap's value and the band transitions' nature. • TM-doped CuO NPs exhibit high adsorption rates, leading to enhanced catalytic activity under sunlight irradiation. • The degradation reaction kinetic obeys the pseudo-first-order kinetic Langmuir-Hinshelwood model. The presence of non-biodegradable, toxic, and harmful organic pollutants in various environmental mediums poses significant threats to ecosystems and human health. This study investigates the impact of transition metal (TM) doping on the photocatalytic performance of copper oxide nanoparticles (CuO NPs) in degrading methylene blue (MB) dye under sunlight irradiation. CuO NPs are synthesized using the co-precipitation method. X-ray diffraction (XRD) analysis revealed a monoclinic structure with space group C2/c for undoped and TM–doped CuONPs, with crystalline sizes ranging from 13 nm for undoped to 36 nm for Zn-doped CuO. Based on UV–Visible Spectroscopy data, the band gap energies and the nature of electronic band transitions are determined using a new simplified calculation method. Accordingly, direct band gap energy exhibits a slight red-shift as a result of doping with Ni, Mn or Fe, from 1.427 eV for undoped to 1.402 eV for Fe-doped CuO. While Co or Zn doping, induces a trivial blue-shift to 1.468 eV and 1.434 eV respectively. The CuO particles show a heterogenous distribution size and shape. The mean grain size raised from 34.3 nm for undoped to about 100 nm for TM-doped CuONPS, excluding the Co-doped CuO for which the mean grain size reached 154.532 nm with highest standard deviation heterogeneity of 125.737 nm. Furthermore, photocatalytic experiments demonstrated that TM-doping significantly enhanced the degradation rate of MB dye under sunlight irradiation. Co-doped CuO is the most efficient catalyst. This makes TM-doping a promising pathway for the use of CuO NPs in wastewater decontamination applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The interaction between doped transition metals (Cr, Mn, Fe, Co) and CeY solid solution has been investigated. • The concentration of surface active oxygen species and oxygen mobility are key factors to control polychlorinated by-products. • A gear-like redox dynamic cycle was formed between transition metal and Ce, which can be accelerated by the enhancement of oxygen mobility. • MnCeYO x solid solution exhibited high catalytic oxidation activity and chlorine poisoning resistance against the elimination of chlorobenzene. Transition metal (Cr, Mn, Fe, Co)-doped CeYO x catalysts were prepared by a co-precipitation method and applied for chlorobenzene elimination. Metal doping caused significant changes in physical properties and chemical environment of CeY solid solution. Intrinsic activity of metals and their interaction with CeY significantly improved the redox performance and oxygen mobility, thus enhancing the catalytic activity and chlorine poisoning resistance. The enhanced concentration and mobility of reactive oxygen can effectively control chlorinated by-products. MnCeYO x can achieve 90 % chlorobenzene conversion at 235 °C, attributing to the promotion of the redox dynamic cycle by the enhanced mobility of active oxygen. [ABSTRACT FROM AUTHOR]

The content of active lattice oxygen and oxygen vacancies is crucial for the catalytic oxidation of soot. Herein, we adjust the Pr-O bond strength in Pr 6 O 11 by doping several common transition metals (Mn, Fe, Co, Ni) to promote the formation of oxygen vacancies and the activation of lattice oxygen. This strategy does not compromise its crystal structure, allowing for improved catalytic performance while maintaining stability. The Mn-doped Pr 6 O 11 catalyst shows the best soot catalytic oxidation performance. Its T 50 (the temperature of soot conversion reaching 50 %) value is 396 °C under loose contact. Further characterizations and density functional theory (DFT) calculations demonstrate that PMO possesses a large specific surface area. Additionally, the weakening the strength of the Pr-O bond leaded to an increase in oxygen vacancies, which in turn enhanced the redox ability of catalyst. This work will provide a reference for the development of Pr-based catalysts for soot combustion. [Display omitted] • Transition metals doped Pr 6 O 11 catalysts were prepared by MOFs derivation method. • Transition metals doping effectively regulate the Pr-O bond strength. • Mn-doped Pr 6 O 11 catalyst has the weakest Pr-O bond strength and the best catalytic performance. • This study provides an idea for the development of Pr-based catalysts for soot combustion. [ABSTRACT FROM AUTHOR]

Bending strain sensors based on one-dimensional ZnO nanorod (NR) arrays cross-linked with interdigitated electrodes were fabricated on polyethylene terephthalate (PET) substrates. ZnO NRs were grown using the hydrothermal method through the dopings with different transition metals, such as Co, Ni, or Co-plus-Ni, on PET substrates, and their microstructural morphology and crystalline properties were examined by a variety of surface analysis methods. Ultraviolet photoresponse and normalized resistance change were measured according to the bending strains to concave and convex directions, and the highest gauge factors of 175 and 83 were achieved in the convex and concave directions, respectively, at a bending strain of 1.75%, when Co-plus-Ni was doped to the NRs.

The demand for lithium is constantly increasing due to its wide range of uses in an excessive number of industrial applications. Typically, expensive lithium-based chemicals (LiOH, LiCl, LiNO3, etc.) have been used to fabricate adsorbents (i.e., lithium manganese oxide) for lithium ion (Li+) adsorption from aqueous sources. This type of lithium-based adsorbent does not seem to be very effective in recovering Li+ from water from an economic point of view. In this study, an innovative nanocomposite for Li+ adsorption was investigated for the first time, which eliminates the use of lithium-based chemicals for preparation. Here, calcium oxide nanoparticles (CaO-NPs), silver-doped CaO nanoparticles (Ag-CaO-NPs), and surfactant (polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS))-modified Ag-CaO (PVP@Ag-CaO and SDS@Ag-CaO) nanocomposites were designed by the chemical co-precipitation method. The PVP and SDS surfactants acted as stabilizing and capping agents to enhance the Li+ adsorption and recovery performance. The physicochemical properties of the designed samples (morphology, size, surface functionality, and crystallinity) were also investigated. Under optimized pH (10), contact time (8 h), and initial Li+ concentration (2 mg L−1), the highest Li+ adsorption efficiencies recorded by SDS@Ag-CaO and PVP@Ag-CaO were 3.28 mg/g and 2.99 mg/g, respectively. The nature of the Li+ adsorption process was examined by non-linear kinetic and isothermal studies, which revealed that the experimental data were best fit by the pseudo-first-order and Langmuir models. Furthermore, it was observed that the SDS@Ag-CaO nanocomposite exhibited the highest Li+ recovery potential (91%) compared to PVP@Ag-CaO (85%), Ag-CaO NPs (61%), and CaO NPs (43%), which demonstrates their regeneration potential. Therefore, this type of innovative adsorbents can provide new insights for the development of surfactant-capped nanocomposites for enhanced Li+ metal recovery from wastewater.

In this work, we combine the CALYPSO method with DFT calculations to conduct a comprehensive structural search of Ta2Bn (n = 10 ∼ 20) clusters. Among all the candidate structures obtained by CALYPSO searching, the structures of ground state Ta2Bn clusters at each size are determined according to their total energy and symmetry. The relative stability analysis indicates that the ground state Ta2B16 and Ta2B18 clusters with the unique bicyclic boron ring and two Ta atoms as axes exhibit excellent stability in the studied range, with their HOMO-LUMO gaps of 2.374 and 2.640 eV, respectively. The bonding analyses reveal that the strong interaction between two Ta atoms and the outer B16/18 bicyclic ring dominates their significant stability, especially the interaction between Ta-d AOs and B-s/p AOs. It is confirmed that both Ta2B16 and Ta2B18 have strong aromaticity by examining the isochemical shielding surface (ICSS). Finally, the strong coupling between their outer boron rings (B16/18) and two Ta atoms inside the structures of Ta2B16 and Ta2B18 is further elucidated by the electronic absorption spectrum (UV–vis and CTS).

Despite being the most favorable ammonia (NH3) gas sensors, metal oxide semiconductors fail to deliver high selectivity and room temperature (RT) sensing. Tuning the metal oxide with doping is an attractive way of overcoming these disadvantages. Herein, we report Mn-doped ZnO microspheres as promising sensors for highly sensitive and selective RT sensing of NH3. ZnO and 2 wt% Mn-doped ZnO microspheres were synthesized by a low-cost and fast solution combustion synthesis, and their structure, morphology, and gas sensing properties were investigated. Mn-doping resulted in a change in the lattice parameters, an increase in the oxygen vacancies, and surface acidity of ZnO as confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Temperature programmed desorption (TPD), respectively. Mn-doped ZnO showed a response (Ra/Rg) of 20.2 in 100 ppm NH3, which is significantly higher than ZnO. The sensor showed high selectivity, three times higher than that of ZnO, and good stability. Improvement in the sensing performance of Mn-doped ZnO is attributed to the increase in the defects and surface acidity with Mn-doping.

The effects of CNC (cellulose nanocrystal) templating and transition metal (TM) doping on the preparation and photocatalytic activity of TiO2 (titania) films were investigated. CNC-templated TiO2 film has superior physical and crystalline properties (crystallite size: 9.95 nm, surface area: 102.6 m2/g) when compared to pure TiO2 film (crystallite size: 12.78 nm, surface area: 76.7 m2/g) due to the CNC template effect. The formation of a mesoporous slit-like pore channel by CNC self-combustion during calcination and an increase in the heterogeneous nucleation rate of the anatase phase are the improvements in the aforementioned properties, which ascribed to the CNC template effect. The CNC template also effectively stabilizes the anatase phase when compared to the mixed anatase/rutile phases found in pure TiO2 film. Further, the prepared CNC-TiO2 was doped with the low (electron acceptor of Co2+) and high (electron donor of Mo5+, Nb5+, and W6+) valence group of TMs into Ti4+ lattice in TiO2. The XPS analysis was used to investigate how low and high valence cations affect the properties of the Ti4+ lattice in TiO2. The photocatalytic performance was evaluated using trichloroethylene (TCE) degradation under a fluorescent light source, which confirmed that TCE conversion was more efficient in the case of high valence cation doping than low valence cation doping. Greater adsorption result was observed in the UV–Vis region for the Mo doped CNC-TiO2 film, demonstrating an excellent photocatalytic activity. This excellent activity is mainly attributed to a highly efficient photoexcited electrons transfer between the conduction and valence bands. Furthermore, the pentad (Mo, Nb) and hexad (W) TMs act as electron donors to TiO2, allowing visible light absorption and creating trap/recombination sites within the TiO2 bands, extending the life of photoinduced charge carriers. [ABSTRACT FROM AUTHOR]

Chromic oxide (Cr 2 O 3) monolayer is a promising alternative hydrogen evolution reaction (HER) catalyst compared with expensive platinum (Pt) due to its advantages such as low cost, large specific surface area, high reserves, and designability. In this study, the two practical strategies, strain engineering and transition metal (TM) doping (Mn, Fe, Zn, etc.), are proposed to activate the catalytic sites of Cr 2 O 3 monolayer for the HER. The density functional theory (DFT) calculations demonstrate that the strained Cr 2 O 3 monolayer can stimulate the HER activity with the Gibbs free energy of hydrogen adsorption (ΔG H∗) close to 0.09eV, which can be considered as a performable strategy to tune the HER catalytic behavior of Cr 2 O 3 monolayer. For the TM doping, it also plays a role in the performance adjustment. These results provide a guideline to optimize the HER performance of Cr 2 O 3 monolayer. [Display omitted] • The HER catalytic behavior of monolayer Cr 2 O 3 is first theoretically predicted. • The HER catalytic behavior of monolayer Cr 2 O 3 could be modulated by the strain. • The TM-doped monolayer Cr 2 O 3 plays a certain role for the HER catalysis. [ABSTRACT FROM AUTHOR]

Cu, Co, and Ti elements were co-doped to SrFe 12 O 19 (SrFe 12-2x Cu x/2 Co x/2 Ti x O 19 , x = 0, 0.05, 0.10, and 0.15) and its physical properties as well as the effects of physical properties on the microwave absorption performance were studied in detail. All samples showed fairly good microwave absorption performance in reflection loss (RL) and effective absorption bandwidth (EAB). For RL, with a thickness of 0.75 mm, all the samples could absorb about 99.99% of the incident microwave. Besides good RL, the enhancement of EAB to reach an ultra-wide frequency range should be noted. Three samples of x = 0, 0.05, and 0.15 could achieve the EAB values of ∼10 GHz. Interestingly, the x = 0.10 samples could reach the EAB value of 15.9 GHz, meaning that this sample could cover almost all the S, C, X, and Ku bands. These results proved that co-doping of Cu, Co, and Ti could enhance the microwave absorption of SrFe 12 O 19 for practical applications. [ABSTRACT FROM AUTHOR]

Silicon is a worthy substitute anode material for lithium-ion batteries because it offers high theoretical capacity and low working potentials vs. Li+/Li. However, immense volume changes and the low intrinsic conductivity of Si hampers its practical applications. In this study, nano/micro silicon particles are achieved by ball milling silicon mesh powder as a scalable process. Subsequent metal (Cu/Fe/Mn) doping into nano/micro silicon by low-temperature annealing, followed by high-temperature annealing with graphite, gives a metal-doped silicon/graphite composite. The obtained composites were studied as anodes for Li-ion batteries, and they delivered high reversible capacities of more than 1000 mAh g−1 with improved Li+ diffusion properties. The full cells from these composite anodes vs. LiCoO2 cathodes delivered suitable energy densities for Li+ storage applications. The enhanced electrochemical properties are accredited to the synergistic effect of metal doping and graphite addition to silicon and exhibit potential for suitable Li+ energy storage applications. [ABSTRACT FROM AUTHOR]

In this work, a series of TiO2 nanostructures doped with well-selected transition metals (Cr, Fe, Co and Zr) was prepared using a simple "one-pot" sol-gel process, followed by a drying under supercritical conditions of solvent. Herein, we carefully highlighted the effect of doping with ions exhibiting higher size than that of Ti4+ host ion, on physicochemical properties of TiO2 aerogel nanomaterials, and its photocatalytic behavior in the methylene blue degradation under solar light irradiation. Textural properties revealed materials with high surface areas given by supercritical drying process. TEM analysis of pristine oxide showed quantum-sized, well-dispersed and highly ordered particles. XRD analysis evidenced an increase in anatase lattice volume after doping. A reduction in gap energy can be seen for Cr, Fe and Co doped TiO2 samples, which is related to the involvement of intermediate energy levels related to dopant ions. Photocatalytic activity of TiO2 solid shows an apparent improvement when doped with zirconium compared to other doped TiO2 materials and pristine oxide, which may be mainly correlated to the increase in the amount of oxygen defects given its larger size as shown by PL spectroscopy. Oxygen vacancies act as electron traps thus provide a charge separation enhancing the photoactivity. The low photoactivity of Cr–TiO2, Fe–TiO2, and Co–TiO2 materials was mainly related to the dopant energy levels appearing as charge recombination centers, which can negatively affect the catalytic efficiency. Hence, the efficiency of photocatalysis seems determined by the competition between these two process; charge separation and charge recombination. [ABSTRACT FROM AUTHOR]

Colloidal core/shell quantum dots (QDs) with environment-friendly feature and controllable optoelectronic properties are promising building blocks in emerging solar technologies. In this work, we rationally design and tailor the eco-friendly CuInSe (CISe)/ZnSe core/shell QDs by Mn doping and stoichiometric optimization (i.e., molar ratios of Cu/In). It is demonstrated that Mn doping in In-rich CISe/ZnSe core/shell QDs can effectively engineer the charge kinetics inside the QDs, enabling efficient photogenerated electrons transfer into the shell for retarded charge recombination. As a result, a solar-driven photoelectrochemical (PEC) device fabricated using the optimized Mn-doped In-rich CISe/ZnSe core/shell QDs (Cu/In ratio of 1/2) exhibits improved charge extraction and injection, showing a ∼ 3.5-fold higher photocurrent density than that of the pristine CISe/ZnSe core/shell QDs under 1 sun AM 1.5G illumination. The findings indicate that transition metal doping in "green" nonstoichiometric core/shell QDs may offer a new strategy for achieving high-efficiency solar energy conversion applications. [ABSTRACT FROM AUTHOR]

Using the first-principles theory, this study explored the electronic behavior and adsorption effect of SO2 on an InP3 monolayer doped with transition metal atoms (Pd, Pt, Au, Fe, Co and Mo). Through calculation and analysis, the optimum doping sites of TM dopants on the InP3 monolayer were determined, and the adsorption processes of SO2 by TM-InP3 monolayers were simulated. In the adsorption process, all TM-InP3 monolayers and SO2 molecules were deformed to some extent. All adsorption was characterized as chemical adsorption, and SO2 acted as an electron acceptor. Comparing Ead and Qt, the order of the SO2 adsorption effect was Mo-InP3 > Fe-InP3 > Co-InP3 > Pt-InP3 > Pd-InP3 > Au-InP3. Except for the Au atom, the other five TM atoms as dopants all enhanced the adsorption effect of InP3 monolayers for SO2. Furthermore, the analysis of DCD and DOS further confirmed the above conclusions. Based on frontier orbital theory analysis, it is revealed that the adsorption of SO2 reduces the conductivity of TM-InP3 monolayers to different degrees, and it is concluded that Pd-InP3, Pt-InP3, Fe-InP3 and Mo-InP3 monolayers have great potential in the application of SO2 resistive gas sensors. This study provides a theoretical basis for further research on TM-InP3 as a SO2 sensor. [ABSTRACT FROM AUTHOR]

In this work, Zn2+ ions doped BiPO 4 photocatalyst was successfully prepared by one-step hydrothermal method for the first time. The degradation rates of the optimal sample on RhB and TC solution reached 91.5 % and 81.25 % under simulated sunlight exposure for 3 and 5 hours, respectively, while pure BiPO 4 only reached 59.22 % and 49.4 %. The improved photocatalytic performance was due to the synergistic effect of oxygen vacancies and built-in electric field. The EPR test demonstrated the generation of more oxygen vacancies in the optimal sample. Additionally, the electrochemical experiments showed that the photocurrent intensity of the optimal sample was about 3 times than that of pure BiPO 4 , indicating an enhanced carrier separation and transfer ability after doping Zn2+ ions. Through density functional theory (DFT), the incorporated Zn2+ ions caused the contraction of crystal structure and the redistribution of charges, leading to a built-in electric field. As few studies pay attention to the relationship between oxygen vacancies and the built-in electric field. This study has enlightening significance for the construction of photocatalysts with oxygen vacancies and built-in electric field through doping engineering. [Display omitted] ● Zn-BiPO 4 was prepared and showed enhanced photocatalytic ability. ● Oxygen vacancies were introduced and a built-in electric field was constructed. ● The degradation path and mechanism were proposed [ABSTRACT FROM AUTHOR]

• Ti, V, Mn and Cu speciation was affected by melting in extreme reducing conditions. • Effects are metal-specific, modulated by crystal field, ionization potential, etc. • Most dramatic effect: suppression of Cu2+ and formation of Cu+ and Cu0 (ruby glass). The influence of an extremely reductive melting atmosphere on the oxidation and coordination states adopted by transition metals in an ultrabasic host was evaluated. An invert glass (46SiO 2 ·11Na 2 O·21CaO·22BaO, basicity = 0.71) was synthesized in container-less conditions, on a jet of Ar−5%H 2. Performed measurements included optical absorption, optical emission and electron paramagnetic resonance spectroscopy. The results revealed that the used atmosphere dramatically decreases the oxidation state(s) dopants assume, compared to those stable under oxidative melting in such a host. After reductive melting: (i) Ti3+ appears alongside Ti4+; (ii) V3+ is added to V5+; (iii) Mn2+ fully substitutes Mn3+ and Mn5+; (iv) Cu2+ is entirely replaced by Cu+and Cu0. These results could be rationalized considering the action of additional factors like ligand-field stabilization energy, ionization energy and special filling numbers of the 3d-subshell. They modulate the interaction between basicity and atmosphere redox character, in a way specific to each transition metal. [ABSTRACT FROM AUTHOR]

[Display omitted] • For the first time, the recently emerged "single-atom catalyst" was used as a support to immobilize Pd nanoparticles for formic acid dehydrogenation at room temperature. • The synergistic effects between highly dispersed transition metal atoms and immobilized Pd nanoparticles on carbon support have been investigated. • A suitable doping of transition metal atoms (Co, Fe and Ni) on support can largely improve the catalytic performance of Pd-based nanocatalysts. • Ultrafine Pd nanoparticles (1.86 nm) immobilized on NC-Co 1% showed an excellent catalytic activity for FA dehydrogenation, with a turnover frequency value of 3045 h−1. Liquid formic acid (FA) dehydrogenation, which needs high-performance catalysts to generate green hydrogen at room temperature, is a promising chemical hydrogen storage technology that can replace fossil fuels in energy-related devices. In this work, a novel nanocatalyst with ultrafine palladium nanoparticles (Pd NPs) immobilized on a transition metal atom-decorated carbon support was synthesized for the dehydrogenation of liquid FA. Via a hydrothermal of glucose and carbonitride with a following Co doping through a heat treatment process, porous carbons with evenly dispersed Co-sites on it were strategically achieved, which could be used as a support for immobilizing Pd NPs. The obtained Pd/NC-Co 1% catalyst exhibited much superior catalytic activities to those samples without Co doping on the support (Pd/NC and PdCo 1% /NC), showing an impressive turnover frequency of 3045 h−1 at 50 °C for FA dehydrogenation. Other transition metal species such as Fe- and Ni-decorated carbon nanocatalysts also showed an improved catalytic activity for FA dehydrogenation. This work not only provides an efficient method to synthesize nanocatalysts with ultrafine metal NPs but also demonstrates that highly dispersed metal atoms on the support can effectively affect the immobilized NPs, resulting in an enhancement of catalytic performance. [ABSTRACT FROM AUTHOR]

The incorporation of transition metals (TMs) such as Co, Fe, and Mn into SnO2 substantially improves the reversibility of the conversion and the alloying reaction when used as a negative electrode active material in lithium-ion batteries. Moreover, it was shown that the specific benefits of different TM dopants can be combined when introducing more than one dopant into the SnO2 lattice. Herein, a careful characterization of Co and Mn co-doped SnO2 via transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction including Rietveld refinement is reported. Based on this in-depth investigation of the crystal structure and the distribution of the two TM dopants within the lattice, an ex situ X-ray photoelectron spectroscopy and ex situ X-ray absorption spectroscopy were performed to better understand the de-/lithiation mechanism and the synergistic impact of the Co and Mn co-doping. The results specifically suggest that the antithetical redox behaviour of the two dopants might play a decisive role for the enhanced reversibility of the de-/lithiation reaction. [ABSTRACT FROM AUTHOR]

Magnetic nanomaterials （MNPs） have been extensively studied and applied in the past half century due to their unique properties including coordinated magnetic properties, non-invasive, easy manipulation, and good biocompatibility. However, the complex magnetic behavior of MNPs is influenced by a variety of factors, including particle size, composition, shape, and core-shell structure. Therefore, the main parameters of MNPs are needed to coordinate accordingly for specific applications to improve their effectiveness. Among them, doping of divalent transition metal ions is a crucial parameter affecting various magnetic properties of MNPs such as magnetic moment （μ）, saturation magnetization strength （Ms ）, coercivity（Hc ）, magnetic crystal anisotropy（K）and relaxation time（τN and τB ）. Therefore, this review focuses on the mechanism of precisely regulating the magnetic properties of magnetic nanomaterials by doping them with transition metal ions, and introduces the potential mechanisms and some recent advances of MNPs doped with transition metal ions for bioimaging detection（magnetic resonance imaging and magnetic particle imaging）, drug precision delivery and tumor therapy, and biosensing. Finally, we summarize some challenges and future trends of MNPs. [ABSTRACT FROM AUTHOR]

Effectively removal of air pollutants using adsorbents is one of the most important methods to purify the air. In this work, we proposed for the first time that PtN3-CNT is an effective adsorbent for air purification. Its air purification performance was studied by calculating the adsorption behaviors and electronic structures of 12 gas molecules, including the main components of air (N2, O2, H2O, CO2) and the most common air pollutants (NO, NO2, SO3, SO2, CO, O3, NH3, H2S), on the surface of PtN3-CNT using first-principles calculations. The results showed that these gases were adsorbed stably via the coordination between Pt and the coordinated atoms (C, N, O, and S atoms) in the gas molecules, and the adsorption energies vary in the range of −0.81∼−4.28 eV. The obvious chemical interactions between PtN3-CNT and the adsorbed gas molecules are mainly determined by the apparent overlaps between the Pt 5d orbitals and the outmost p orbitals of the coordination atoms. PtN3-CNT has strong adsorption capacity for the toxic gas molecules, while relatively weaker adsorption performance for the main components of the air except oxygen. The recovery time of each adsorbed molecule calculated at different temperatures showed that, CO2, H2O, and N2 can be desorbed gradually at 298∼498 K, while the toxic gases are always adsorbed stably on the surface of PtN3-CNT. Considering the excellent thermal stability of PtN3-CNT at up to 1000 K proved by AIMD, PtN3-CNT is very suitable to act as an adsorbent to remove toxic gases to achieve the purpose of air purification. Our findings in this report would be beneficial for exploiting possible carbon-based air purification adsorbents with excellent adsorbing ability and good recovery performance.

First principles calculations have been used to verify the ability for sensing nitrobenzene by the host systems, pristine C24 and transition metal (TM) doped C24, viz., C24+TM (TM = Sc, Cr and Mn). All the TM doped host systems are energetically stable which is confirmed from their negative values of binding energy. To get a clear view of the participation of the orbitals of different atoms of the host and how they are modified on the adsorption of nitrobenzene, density of states has been explored. Finally, charge transfer between the hosts and the guest is also calculated. Nitrobenzene is adsorbed on both pristine and TM doped C24 fullerene, but with reasonable adsorption energy and achievable recovery time, Sc doped C24 emerges as the best sensor device for sensing nitrobenzene among the TM doped fullerenes. [ABSTRACT FROM AUTHOR]

In this study, first-row transition metal-doped calcium oxide materials (Mn, Ni, Cr, Co., and Zn) were synthesized, characterized, and tested for the OCM reaction. Doped carbonate precursors were prepared by a co-precipitation method. The synthesis parameters were optimized to yield materials with a pure calcite phase, which was verified by XRD. EPR measurements on the doped CaO materials indicate a successful substitution of Ca2+ with transition metal ions in the CaO lattice. The materials were tested for their performance in the OCM reaction, where a beneficial effect towards selectivity and activity effect could be observed for Mn, Ni, and Zn-doped samples, where the selectivity of Co- and Cr-doped CaO was strongly reduced. The optimum doping concentration could be identified in the range of 0.04-0.10 atom%, showing the strongest decrease in the apparent activation energy, as well as the maximum increase in selectivity.

Crystalline transition-metal chalcogenides are the focus of solid state research. At the same time, very little is known about amorphous chalcogenides doped with transition metals. To close this gap, we have studied, using first principle simulations, the effect of doping the typical chalcogenide glass As2S3 with transition metals (Mo, W and V). While the undoped glass is a semiconductor with a density functional theory gap of about 1 eV, doping results in the formation of a finite density of states (semiconductor-to-metal transformation) at the Fermi level accompanied by an appearance of magnetic properties, the magnetic character depending on the nature of the dopant. Whilst the magnetic response is mainly associated with d-orbitals of the transition metal dopants, partial densities of spin-up and spin-down states associated with arsenic and sulphur also become slightly asymmetric. Our results demonstrate that chalcogenide glasses doped with transition metals may become a technologically important material.

Electronic structures and optical properties of transition metal (TM, TM refers to Ru, Rh and Pd, respectively) doped GaSb were studied by first-principles calculations. The results show that the three TMs are more likely to substitute for Ga to form TM@Ga defect and enhance the response of GaSb semiconductor to infrared photons, making the optical absorption edge of the system red shift. The doped TM@Ga introduce impurity levels distributed around the Fermi level in the band gap, which greatly strengthens the dielectric properties of the system. The enhancement of the photoelectric field intensity can promote the generation and migration of electron-hole pairs, thus improving the photoelectric conversion efficiency of GaSb semiconductor. The optical properties of TM@Ga doped GaSb are all superior to that of undoped system, but Ru is the best choice among the three dopants. Moreover, the molar concentration and location of Ru also have an impact on optical properties of GaSb semiconductor. The absorption amplitude of Ru-GaSb is the biggest when the concentration is 6.25% (atomic fraction), which can improve the photoelectric conversion efficiency and photocatalytic performance effectively. [ABSTRACT FROM AUTHOR]

[Display omitted] Mn oxide-doped activated carbon microspheres (MnO x /ACS) with super-high adsorption capacity and deep removal capability for Cr(VI) simultaneously were successfully prepared via an ammonium persulfate assisted hydrothermal method and a followed potassium oxalate activation process. This highly efficient method can also be extended to prepare V-, Mo-, W-doped carbon spheres with enhanced adsorption performance for Cr(VI) compared to the bare activated carbon spheres suggesting their good application potential in the field of wastewater treatment. Mn-doped activated carbon microspheres (MnO x /ACS) with super-high adsorption capacities and deep removal capability for hexavalent chromium (Cr(VI)) were successfully prepared via an ammonium persulfate-assisted hydrothermal method followed by potassium oxalate activation using KMnO 4 and sucrose as raw materials. Their -physical and chemical properties, as well as those of Mn-doped non-activated carbon spheres (MnO x /CS), were characterized by XRD, SEM, TEM, EDS-mapping, XPS, N 2 adsorption–desorption, ICP-AES, and elemental analysis. It was found that the manganese oxide (MnO x) particles were uniformly embedded within the carbon spheres via layer-by-layer capture, and the MnO x /ACS exhibited strong redox activity because of the multivalent nature of MnO x , resulting in excellent adsorption performance via reduction. In particular, MnO x /ACS-4 with a Mn content of 1.06 wt% and a specific surface area of 1405.7 m2 g−1 achieved a maximum adsorption capacity of 660.7 mg g−1; this can reduce Cr(VI) content to less than 0.05 mg L-1, which meets the corresponding Chinese drinking water quality standard when the initial concentration of Cr(VI) is less than 400 mg L-1. Furthermore, this highly efficient method can be extended to prepare V-, Mo-, or W-doped carbon microspheres with significantly enhanced adsorption performance for Cr(VI) compared to bare activated carbon sphere, indicating their good application prospect for the deep removal for heavy metal ions from wastewater. [ABSTRACT FROM AUTHOR]

Surface engineering of transition metal layered double hydroxides (LDHs) provides an efficient way of enhancing their catalytic activity toward the oxygen evolution reaction (OER). However, the underlying mechanism of atomistic doping or heterogeneous interface with foreign atom is still ambiguous. Herein, a case study of NiFe‐LDHs that are homogeneously doped with Ce (CeNiFe‐LDH) and interfaced with Ce(OH)3 (Ce@NiFe‐LDH), which elucidates their electronic modulation, in situ evolution of active site, and catalytic reaction mechanisms by using X‐ray photoelectronic spectroscopy, operando electrochemical Raman spectroscopy, and first‐principles density functional theory (DFT) calculations, is reported. The results indicate that Ce and Fe atoms serve as the electron acceptors and facilitate the coupled oxidation of Ni3+/4+ in NiFe‐LDH, and the activated oxyhydroxide phase of the catalysts exhibits superior catalytic activity for water oxidation. Especially, Ce@NiFe‐LDH shows a stronger electron transfer between the loaded Ce(OH)3 and the matrix, which leads to a better catalytic activity than CeNiFe‐LDH. DFT calculations provide a clear picture with atomistic resolution for charge redistribution in the NiFe‐LDH surface induced by Ce, which eventually leads to the optimal free energy landscape for the enhanced OER catalytic activity. [ABSTRACT FROM AUTHOR]

In the quest for active and inexpensive (photo)electrocatalysts, atomistic simulations of the oxygen evolution reaction (OER) are essential for understanding the catalytic process of water splitting at solid surfaces. In this paper, the enhancement of the OER by first‐row transition‐metal (TM) doping of the abundant semiconductor ZnO was studied using density functional theory (DFT) calculations on a substantial number of possible structures and bonding geometries. The calculated overpotential for undoped ZnO was 1.0 V. For TM dopants in the 3d series from Mn to Ni, the overpotentials decreased from 0.9 V for Mn and 0.6 V for Fe down to 0.4 V for Co, and rose again to 0.5 V for Ni and 0.8 V for Cu. The overpotentials were analyzed in terms of the binding to the surface of the species involved in the four reaction steps of the OER. The Gibbs free energies associated with the adsorption of these intermediate species increased in the series from Mn to Zn, but the difference between OH and OOH adsorption (the species involved in the first, respectively the third reaction step) was always in the range 3.0–3.3 eV, despite a considerable variation in possible bonding geometries. The bonding of the O intermediate species (involved in the second reaction step), which is optimal for Co, and to a somewhat lesser extend for Ni, then ultimately determined the overpotential. These results implied that both Co and Ni are promising dopants for increasing the activity of ZnO‐based anodes for the OER. [ABSTRACT FROM AUTHOR]

We studied the direct conversion of CO2 to HCOOH through hydrogenation reaction without the presence of base additives on the transition metal-doped subnanometer palladium (Pd7) cluster (PdxM: M = Cu, Ni, Rh) by using a combination of density functional theory and microkinetic calculations. It was shown that the CO2 hydrogenation on Pd7 and Pd6M clusters are more selective towards the formate pathway to produce HCOOH than the reverse water gas shift pathway to produce CO. Inclusion of Ni and Rh doping in the subnanometer Pd7 cluster could successfully enhance the turnover frequency (TOF) for CO2 hydrogenation to formic acid at low temperature. The order of TOF for formic acid formation is as follows: Pd6Ni > Pd6Rh > Pd7 > Pd6Cu. This order can be explained by the trend of the activation energy of CO2 hydrogenation to formate (HCOO*). The Pd6Ni cluster has the highest TOF value because it has the lowest activation energy for the formate formation reaction. The Pd6Ni system also has a superior TOF profile for HCOOH formation compared to several metal surfaces in low and high-temperature regions. This finding suggests that the subnanometer PdxNi cluster is a promising catalyst candidate for direct CO2 hydrogenation to formic acid. [ABSTRACT FROM AUTHOR]

As an effective method to improve the surface catalytic activity of catalysts, crystal plane engineering has become a research hot spot in recent years. Doping regulation of the highly exposed facet with low surface energy is helpful to expand their applications in the field of photocatalysis. Therefore, low concentration transition metal ions (Co2+) in the high exposure surface (100) of WS2 by one‐pot hydrothermal method are doped. Moreover, density functional theory (DFT) calculation shows that after Co2+ in WS2 (100) crystal replaces W4+, the surface charge is rearranged, and the local charge near Co2+ is enhanced, which accelerates the electron transfer rate, makes the electron transfer rapidly to (100) facet through the secondary transfer process, and finally promotes proton reduction. Therefore, the hydrogen production efficiency of 7% (Co–WS2)/Cd0.4Zn0.6S (CZS) Schottky junction (21 000 μmol g−1 h−1) is 9.3 times and 1.3 times higher than that of CZS (2265 μmol g−1 h−1) and 7% WS2/CZS heterojunction (17 000 μmol g−1 h−1). This study has certain reference and guiding significance for the study of new cocatalysts, not only on pristine semiconductor but also for semiconductor‐based hybrid structures. [ABSTRACT FROM AUTHOR]

This study focused on investigating the adsorption and detection performance of intrinsic and Au, Ag, Cu doped monolayers of molybdenum disulfide (MoS 2) for air pollutants (NO 2 , NH 3 , CH 4 , CO 2 , SO 2 , and SO 3). By using first-principles density functional theory (DFT), calculations were performed on parameters related to structural properties, electronic properties, and adsorption properties. Besides, the possibility of applications was further explored by considering the work function (WF), optical absorption coefficient, thermodynamic stability, and desorption performance. Firstly, the adsorption energy (E ads) showed that the position of doped atoms (Au, Ag, and Cu) in the MoS 2 substrate directly affects gas selectivity and improves the adsorption of gas molecules to different degrees. Obviously, when NO 2 is adsorbed onto a substrate of Cu-substituted S-doped MoS 2 (Mo x S 2x-1 Cu), the E ads are observed to be 9.9 times higher than that of intrinsic MoS 2. Moreover, the charge transfer of gas absorbed is enhanced after doping atoms, with a maximum increase of 6.9 times. Secondly, in doped adsorption gas systems, the WF increases by at least 27.3%, along with a significant increase in the absorption coefficient in the visible light region. It is also indicated that the presence of doped atoms enhances the gas sensitivity of MoS 2. According to the desorption time, Mo x S 2x-1 Cu–NH 3 and Mo x-1 AuS 2x -SO 3 can achieve rapid desorption after being artificially heated. The desorption time can be as fast as 10 s. This work is found to elucidate the gas adsorption mechanism of doped MoS 2 materials, which provides a solid theoretical foundation for enhancing the detection capability of gas sensors using modified MoS 2 -sensitive materials. • The adsorption and desorption behavior of six hazardous gases on TM-doped MoS 2 were studied. • Based on DFT studies, the gas selectivity of TM-doped MoS 2 substrates was predicted. • Laying the theoretical foundation for the preparation of selective and sensitive MoS 2 gas sensors for hazardous gases. [ABSTRACT FROM AUTHOR]

This work utilizes a multi-scale computational approach combining first-principles density functional theory (DFT) and Monte Carlo statistical simulations to provide fundamental insights into the impacts of vanadium (V) doping on the structural, electronic, magnetic, and thermodynamic properties of wurtzite zinc sulfide (ZnS). 2 × 2 × 2 ZnS supercells with controlled V doping concentrations from 12.5%–25% substituting zinc sites were constructed. The introduction of V dopants induces systematic expansions in lattice parameters and cell volume, attributed to the larger ionic radius of V 2 + than Zn 2 + , while the average compressibility shows minimal variation. However, V incorporation is found to soften ZnS by over 15% at higher dopant contents, increasing compliance and anisotropy. Stable ferromagnetic spin couplings emerge, mediated by host carriers without precipitating V secondary phases. The band structure develops half-metallic electronic properties with the lifting of spin degeneracy and preferential spin-up band metallicity induced by V-3d and S-3p hybridization effects. This results in 100% spin polarization at the Fermi level. Monte Carlo simulations based on a tight-binding Hamiltonian constructed from maximally localized Wannier functions to accurately calculate the exchange interactions between V spins successfully reproduce the magnetic phase transition behavior. The results confirm high Curie temperatures exceeding 300 K at 25% V, attributable to the significant strengthening of short-range ferromagnetic couplings over antiferromagnetic interactions. The integrated computational approach provides fundamental insights into the microscopic origin of carrier-mediated ferromagnetism in V-doped wurtzite ZnS dilute magnetic semiconductors. The systematic first-principles calculations and statistical mechanics modeling establish clear structure–property relationships linking V doping configurations and concentrations to tuned mechanical response, enhanced stability, electronic structure modifications, spin polarization, and magnetic ordering temperatures in ZnS. The results present design pathways and predictive capabilities to guide experimental efforts toward emerging high-performance magnetic materials for spintronic technologies. [Display omitted] [ABSTRACT FROM AUTHOR]

Microwave-absorbing materials (MAMs) are essential for mitigating the unwanted effects of electromagnetic interference and microwave pollution. MAMs are also used in 5G technology, energy harvesting, information security, and military technology (such as reduced radar cross-section). In this work, SrFe 12–2x Cu x/2 Co x/2 Ti x O 19 samples, prepared by using a ball mill and heat treatment method, showed their superior microwave dissipation features in both effective absorption bandwidth (EAB) and reflection loss (RL) values for the microwave incident angle of 0°, where EAB and RL values reached 15.90 GHz and −42.86 dB, respectively. The optimum RL values would change with the variation of the incident microwave angle. RL values at a specific oblique angle could exhibit better RL values for both transverse electric (TE) and transverse magnetic (TM) polarization modes, except for the x = 0.15 (SrM15) sample for TE mode. In detail, the x = 0 (SrM0) sample achieved the lowest RL value of −71.28 dB for the incident angle of 20° in the TE polarization mode, which was much better than that of the normal incident. The RL of the SrM15 sample in TM mode was significantly enhanced and reached a value of −66.48 dB for an incident angle of 10°. The increase in the RL values resulted from the superior values of complex permittivity and permeability and their matching. In addition, the improvement in RL values could be attributed to the increase in incident and refraction angles as well as the longer pathway of the microwave inside the samples. These discoveries also illustrate that SrFe 12–2x Cu x/2 Co x/2 Ti x O 19 samples hold promise for various everyday applications, even when exposed to oblique angle variation. [Display omitted] • SrFe 12-2x Cu x/2 Co x/2 Ti x O 19 microwave-absorbing samples were successfully prepared. • Samples exhibited excellent values for both RL (=−42.86 dB) and EAB (=15.90 GHz). • x = 0 sample achieved an RL of −71.28 dB for an incident angle of 20° (TE mode). • x = 0.15 sample reached an RL of −66.48 dB for an incident angle of 10° (TM mode). • These samples could be used as promising MAMs for practical applications. [ABSTRACT FROM AUTHOR]