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Poor mass transfer behavior and inherent activity limit the efficiency of traditional catalysts in electrocatalyzing carbon dioxide reduction reactions. However, the development of novel nanomaterials provides new strategies to solve the above problems. Herein, we propose novel single‐metal atom catalysts, namely diamane‐based electrocatalysts doped with Cu, Fe, and Ni, explored through density functional theory (DFT) calculations. We thoroughly investigated the doping pattern and energetics for different dopants. Furthermore, we systematically investigated the conversion process of CO2 to C1 or C2+ products, utilizing the free energy analysis of reaction pathways. Our results reveal that dopants could only be introduced into diamane following a specific pattern. Dopants significantly enhance the CO2 adsorption ability of diamane, with Fe and Ni proving notably more effective than Cu. After CO2 adsorption, Cu‐ and Fe‐doped diamane prefer to catalyze CO2RR, while Ni‐doped diamane favors hydrogen evolution reaction (HER). The C−C coupling reaction on Cu‐hollow diamane, Cu‐bridge diamane, and Fe‐hollow diamane tends to be from C2+ products. Among all examined catalysts, Cu‐hollow diamane shows better electro‐catalytic performance. Our study demonstrates the feasibility of and contributes to the development of diamane‐based electro‐catalysts for CO2RR. [ABSTRACT FROM AUTHOR]

As calcium silicate hydrate (C-S-H) is the main binding phase in concrete, understanding the doping behavior of impurity elements in it is important for optimizing the structure of cementitious materials. However, most of the current studies focus on cement clinker, and the doping mechanism of impurity elements in hydrated calcium silicate is not yet fully understood. The hydrated calcium silicate component is complex, and its structure is very similar to that of the tobermorite mineral family. In this study, the effects of three different dopants (Mg, Sr and Ba) on a representing structure of C-S-H—tobermorite—was systematically explored using densify functional theory (DFT) calculations. The calculations show that Mg doping leads to a decrease in lattice volume and causes obvious structure and coordination changes of magnesium–oxygen polyhedra. This may be the reason why high formation energy is required for the Mg-doped tobermorite. Meanwhile, doping only increases the volume of the Sr- and Ba-centered oxygen polyhedra. Specifically, the Mg-doped structure exhibits higher chemical stability and shorter interatomic bonding. In addition, although Mg doping distorts the structure, the stronger chemical bonding between Mg-O atoms also improves the compressive (~1.99% on average) and shear resistance (~2.74% on average) of tobermorillonite according to the elastic modulus and has less effect on the anisotropy of the Young's modulus. Our results suggest that Mg doping is a promising strategy for the optimized structural design of C-S-H. [ABSTRACT FROM AUTHOR]

The density functional theory (DFT) method was used to study the adsorption of CO 2 molecules on pristine and doped phosphorenes. Twenty dopants were considered during this study: Fe, Co, Ni, Ti, Cu, Au, Ag, Ca, Cr, Pd, Pt, V, Sr, Mn, B, C, N, O, Si, Ge, Se, and S. Two initial configurations of CO 2 on the pristine and doped phosphorenes were also studied. The results for adsorption energy, isosurface of electron density difference, partial density of states, and charge transferring analysis indicated that pristine phosphorene had a very weak interaction with CO 2 . Some of transition metallic dopants, namely Fe, Co, Ti, Ni, Cr, and V, significantly improved the interactions between phosphorenes and CO 2 . Some other metallic dopants, however, namely Au, Ag, Pd, and Pt, and nonmetallic dopants, namely Ge, Si, Se, S, N, C, B, and O had negligible effect on the interactions between CO 2 and phosphorene. Cr, Fe, Ti and V-doped phosphorenes had the potential to enhance CO 2 adsorption with a particular CO 2 configuration. The role of charge donor or acceptor changed between CO 2 and (V- Cr-, Fe-, and Ti-) doped phosphorenes when the initial CO 2 configuration changed. Thus, the use of transition metallic dopants was an effective way to enhance the interactions between CO 2 and phosphorene. In particular, (V- Cr-, Fe-, and Ti-) doped phosphorenes showed the potential to sense or capture CO 2 molecules. [ABSTRACT FROM AUTHOR]

In this research, the potential application of metal-doped g -C 3 N 4 as highly sensitive molecule sensors for NO 2 detection was studied using density function theory (DFT) calculations. Various metal-doped (Ag-, Au-, Co-, Cr-, Cu-, Fe-, K-, Li-, Na-, Mn-, Pt-, Pd-, Ti-, V-) g -C 3 N 4 sheets were considered. CO, CO 2 , NH 3 , N 2 and NO 2 molecules were found to adsorb on metal-doped g -C 3 N 4 via strong chemical bonds. Chemisorbed gas molecules and metal-doped g -C 3 N 4 formed charge transfer complexes with different charges transferring from metal-doped g -C 3 N 4 to gas molecules. Pristine and metal-doped g -C 3 N 4 sheets were demonstrated as potential capturers for certain gas molecules according to the adsorption energy, isosurface of electron density difference, and density of states analysis. Among the diverse metal-doped g -C 3 N 4 sheets, Ag-, K-, Na-, and Li-doped g -C 3 N 4 were found to be clearly sensitive to the NO 2 molecule. The adsorption energies between NO 2 and Ag-, K-, Na-, and Li-doped g -C 3 N 4 were significantly greater than those of the other gas molecules (CO, CO 2 , N 2 , and NH 3 ). The density of states indicates that the NO 2 adsorption on Ag-, K-, Na-, and Li-doped g -C 3 N 4 induced the shift of the total density of state in the positive energy direction. Charge transfer results also demonstrate that chemical interactions existed between NO 2 and Ag-, K-, Na-, and Li-doped g -C 3 N 4 . All these results suggest the strong potential of Ag-, K-, Na-, and Li-doped g -C 3 N 4 for application as highly sensitive molecule sensors. [ABSTRACT FROM AUTHOR]

Hydrogen capture and storage is the core of hydrogen energy application. With its high specific surface area, direct bandgap, and variety of potential applications, phosphorene has attracted much research interest. In this study, density functional theory (DFT) is utilized to study the interactions between doped phosphorenes and hydrogen molecules. The effects of different dopants and metallic or nonmetallic atoms on phosphorene/hydrogen interactions is systematically studied by adsorption energy, electron density difference, partial density of states analysis, and Hirshfeld population. Our results indicate that the metallic dopants Pt, Co, and Ni can help to improve the hydrogen capture ability of phosphorene, whereas the nonmetallic dopants have no effect on it. Among the various metallic dopants, Pt performs very differently, such that it can help to dissociate H 2 on phosphorene. Specified doped phosphorene could be a promising candidate for hydrogen storage, with behaviors superior to those of intrinsic graphene sheet. [ABSTRACT FROM AUTHOR]

Polychlorinated dibenzo-p-dioxins (PCDDs) are highly toxic to humans. The search for novel and effective methods and materials for detecting or removing these gas pollutants is becoming more important and urgent. With its high specific surface area, abundance, and variety of potential applications, phosphorene has attracted much research interest. In this study, density functional theory was used to study the interactions between a doped phosphorene sheet and a tetrachlorodibenzo-p-dioxin (TCDD) molecule. The initial configurations of the TCDD and metallic (Ca or Ti) or nonmetallic (S and Se) dopants were investigated during the TCDD–phosphorene interaction study. Adsorption energy, isosurface of electron density difference, and density of states analysis were utilized to explore the interactions between TCDD and phosphorene. The results indicated that Ca dopant effectively improved the interaction between TCDD and phosphorene. Se dopant reduced the interaction between TCDD and phosphorene. Combining interactions between TCDD and the pristine, Ca-doped, and Se-doped phosphorenes, phosphorene could be a promising candidate for TCDD sensing and removal. [ABSTRACT FROM AUTHOR]

The exploration of novel sensors for NO 2 detection is particularly important in material and environmental sciences. In this work, the HOMO–LUMO gap of graphene, Ti- or N-doped graphene is investigated by DFT methods. The adsorption of NO 2 , NO, and O 2 on Ti- or N-doped graphene of different sizes is also explored. Results reveal that the interactions between gases (NO 2 , NO, and O 2 ) and Ti- or N-doped graphenes is not affected by the size of graphene. The doped Ti greatly improves the interactions between gases and graphene whereas the doped N has no effect on those interactions. The HOMO– LUMO gap of Ti-doped graphene can be modulated by adsorption of the gases. The cross effect of the NO and O 2 is also investigated, and it is demonstrated that Ti-doped graphene has specific interactions with NO 2 . Thus, Ti-doped graphene can be a candidate for NO 2 sensor materials. Furthermore, doping the graphene with Ti or N improves the sensitivity of the sheets toward NO 2 , which can be trapped and detected by the intrinsic graphene. Efficient sensors are rationally designed to diversify their applications in environmental science and engineering. [ABSTRACT FROM AUTHOR]

The effects of different doped atoms on the interactions between graphene sheets and MgH 2 molecules were investigated by density functional theory calculations. From the calculations, graphene sheets doped with Pt, Fe, and Ti had the highest interaction energy with MgH 2 molecules, followed by F, Cl, and Al, and then by B and N. Moreover, Pt, Fe, and Ti positively affected H desorption from MgH 2 , whereas B, N, and intrinsic graphene had no obvious effect. Our results can serve as a basis for adjusting the hydrogen adsorption/desorption reaction rates of MgH 2 when using graphene-based materials. [ABSTRACT FROM AUTHOR]

Abstracts Understanding the interaction mechanisms of hydrogen sulfide (H 2 S) with graphene is important in developing graphene-based sensors for gas detection and removal. In this study, the effects of doped Fe atom on interaction of H 2 S with graphene were investigated by density functional theory calculations. Analyses of adsorption energy, electron density difference, and density of states indicated that the doped Fe atom can significantly improve the interaction of H 2 S gas molecules with graphene, as well as Pt-doped graphene. The location of the sulfur atom is important in the interactions between H 2 S and Fe-doped graphene. The influence of the Fe S distance can be very weak within a certain distance, as simulated in this study. [ABSTRACT FROM AUTHOR]

The electrocatalytic activity of graphene for CO 2 reduction can be improved and regulated by the bimetallic atom doping. [Display omitted] • The CO 2 reduction process on three different bi-metal doped graphenes were systematically studied by free energy diagrams and overpotentials analysis. • Bimetal doping enhances the electrocatalytic properties of graphene for CO 2 reduction. • Among the three bi-metal doped graphenes, Cu_Ni/DG exhibits the higher catalytic activity with the lowest overpotential. Developing efficient and inexpensive electrocatalysts for CO 2 reduction reaction (CRR) has been a key scientific issue. Several factors limit the electrocatalyst efficiency of materials, including the relatively high overpotential, low stability and low selectivity for CRR. The use of bimetallic catalyst systems is an efficient approach to improve the catalytic performance. In this study, by using the density functional theory (DFT) calculations, we explore the CRR processes of three different bimetal doped graphenes (M1M2/DG (M1, M2 = Cu, Fe, Ni)). Various reduction reaction pathways of CO 2 lead to different products, including CH 4 , CH 3 OH, HCOOH and CO. The E ads of different intermediates on different M1M2/DG, the free energy variation and the overpotential of the different M1M2/DG were analyzed. The obtained results confirm the CO 2 capture ability of all the studied M1M2/DG systems. The low overpotential of 0.49 V for Cu_Ni/DG is even lower than that of the most outstanding metallic electrocatalyst (Cu (2 1 1)). This work provides useful information for the development of efficient CRR electrocatalysts. [ABSTRACT FROM AUTHOR]

In this study, the interactions between mica and soil organic matters (SOMs) are investigated by the density functional theory (DFT) calculations. The adsorption behavior of 12 typical SOMs on X-mica (X = Na, K or Cs) are systematically studied based on 96 interaction models. Three typical adsorption configurations for each SOMs are considered. The interactions details are explored by the further analysis of E ads , isosurface of the electron density difference, electrostatic potential, and the NCI plot. The E ads between mica and SOMs is proved strong for Na-mica due to the smallest ionic radius of Na. For example, it is 0.78 eV. 0.48 eV, 0.27 eV for CH 4 O/Na-mica, K-mica and Cs-mica respectively. The SOM S with functional groups, including -OH, -COOH, -C=O, -SO- and pyridine, own the largest E ads with X-mica, while the SOMs containing benzene ring have a stronger E ads than that of the hydrocarbon alkyl. The Light Gradient Boosting Machine (LGBM) method is used to analyses the importance of the different factors in regulating the SOMs/X-mica interactions. The electronegativity and ionic radius of cations in X-mica are found to be the most important factors, followed by the configurations and functional groups of SOMs. This work provides a detailed DFT based method for SOM/minerals interactions which provide deep understanding on effects of SOM in the mineral morphogenetic transformation. • The adsorption of 12 typical SOMS on X-mica (X = Na, K or Cs) are systematically studied by DFT method. • The electronegativity and ionic radius of cations in X-mica are found to be the most important factors for the interfacial interactions. • This study provides deep understanding on effects of SOM in the mineral morphogenetic transformation. [ABSTRACT FROM AUTHOR]

The laser ignition behavior of CL-20 can be regulated by the fluorination degree of fluorinated graphene. [Display omitted] • The adsorption energy of CL-20 on fluorinated graphene was systematically studied. • The fluorination modification enhances the heat release of graphene. • Graphene with a low fluorination degree exhibits good laser ignition behavior. Fluorinated graphene (FG) as energetic material has a wide range of application due to its unique light-to-heat conversion, thermal and oxidation properties. The structure of FG, especial the fluorinated degree of FG is a key parameter to achieve those applications. In this study, the effect of the fluorinated degree of FG on the laser ignition of a typical energetic material of 2,4,6,8,10,12-(hexanitrohexaaza) cyclododecane (CL-20) was studied by the density functional theory (DFT) calculations and experimental characterizations. The interaction mechanism between the FG and CL-20 was studied by the simulation through adsorption energy and the electron density difference variations. Simultaneously, graphene materials with different fluorinated degrees were prepared by the hydrothermal method experimentally, the photothermal conversion behavior and laser ignition characteristics of graphene with different degrees of fluoride were characterized. Simulation and experimental results show that CL-20 and graphene with a low degree of fluorination have stronger adsorption energy and lower laser induced ignition delay time than those of the other conditions. This research provides an atomic-scale explanation for the laser induced ignition mechanism of fluorinated graphene in energetic materials. [ABSTRACT FROM AUTHOR]

Cu-, O- and Pd-doped graphenes are preferred candidates for glyphosate adsorbents. [Display omitted] • Ca-, O-, and Pd-doped graphene are favourable than the Ti-, V-, Cr-, B-, N-, Pt-, and Cu-doped. • All the dopants can be an enhancer for the glyphosate adsorption, the phosphate group of glyphosate is the most active group. • The electronegativity of the dopants plays the important role in the glyphosate capture ability. • Cu-, O- and Pd-graphene are regarded to be the candidates for glyphosate adsorbents. The potential hazards of glyphosate on human health and ecological system cause widespread concern while being extensively accepted as a low side effects herbicide. Carbon based adsorbents are promising candidates for removal glyphosate. In this study, the ab initio calculations are carried out to explore the effects of ten different elemental dopants on the glyphosate capture ability of graphene. The results indicate that elemental doping can be an effective way to improve the interactions between glyphosate and graphene. Considering the interactions between dopants and graphene, including their interfacial interactions, Cu-, O- and Pd-doped graphenes are outstanding candidates for glyphosate adsorbents. [ABSTRACT FROM AUTHOR]

[Display omitted] • Elemental doping and interstitial O are most easily generated defects on calcite (1 0 4). • Water adsorption is apparently enhanced by the calcite (1 0 4) surface defects. • Water is easily dissociated on - CO 3 vacancy defected calcite (1 0 4) surface. • The activation energy of water dissociation is greatly related to the ICOHP of the dopants - O of water atom pairs. Defect-dominated regulation on water adsorption or dissociation on calcite surface is crucial in several important areas including the geochemistry of calcite, haze formation, which is caused by calcite based mine dust, inorganic material design and so on. Here, density functional theory (DFT) method has been utilized to systematically investigate the behavior of water on various calcite {1 0 4}surfaces, focusing on the effect of defects, including doping defected (Co-, Mg-, Mn-, Zn-, and Cu-doped), vacancy-defected (Ca or CO 3), and the interstitial O calcite {1 0 4} surfaces. As demonstrated, although all the defects enhance the water adsorption, the enhancement degree varies with the defects type that the vacancy defects exhibit more remarkable role. The activation energy of water dissociation is greatly related to the integrated crystal orbital Hamilton populations (ICOHP) energy of the dopants - O of water atom pairs in the water-calcite {1 0 4} surface interaction systems. It indicates that water is easily dissociated on - CO 3 vacancy-defected calcite {1 0 4} surface. Our study can be helpful for the understanding of the water adsorption and dissociation on defected calcite surfaces. [ABSTRACT FROM AUTHOR]

Strain induced variation of the PFOS adsorption on the single vacancy defected phosphorene (Yellow: electrons accumulation; Blue: electrons depletion). • The effects of the typical defects on the adsorption of PFOS on graphene are studied by DFT methods. • The PFOS adsorption on phosphorene is found to be sensitive with the strain direction. • The SV defected phosphorene exhibits the significant capability to attract PFOS due to the dicoordinated phosphorous. • The synergistic effect of the SV defect and strain on PFOS adsorption is confirmed. Adsorption of per- and polyfluoroalkyl substances (PFAS) such as perfluorooctane sulfonate (PFOS), is a key issue in the environmental area now but not yet fully understood. As a monolayer adsorbent, phosphorene has attracted a body of research interests. Defects and strain are reported to be important for its electronic structure regulations. In this work, we use the density functional theory (DFT) calculations to explore the adsorption of PFOS on the pristine, the Stone-Wales defected (SW), the single vacancy defected (SV) and the double vacancy defected phosphorenes (DV), respectively. Moreover, the effects of the strain of phosphorene along both a- and b- directions (two directions of a monolayer) on the PFOS adsorption are systematically investigated by analyzing the adsorption energy (E ads), electron transferring and the partial density of states. Finally, the synergistic effects of SV defects and tensile strain of phosphorene towards the enhancement of PFOS adsorption is proposed. [ABSTRACT FROM AUTHOR]

• The effects of the Al, Mn, Fe, Ni, Co and Si doping on the electronic structures of kaolinite are studied by DFT methods. • The CO 2 adsorption strength depends on the –OH groups on kaolinite surfaces and the atomic radius of the dopants. • The adsorption strength of CO 2 on different types of kaolinites Si dopant induces the strongest interactions between CO 2 and kaolinites. • Some of the key factors that controlling the interactions between CO 2 and kaolinites are identified. The CO 2 adsorption on clay minerals such as kaolinite, mica and et al. attracts lots of research attentions for the potential applications in slowing down the greenhouse effect. The physical and chemical properties of kaolinites can be adjusted by the internal atomistic structures, especially the substitution of Al in the Al-O tetrahedrons. In this work, we utilize the density functional theory (DFT) calculations to explore the variation of the electronic structures of kaolinite before and after the elemental substitution of Al by Mn, Fe, Co, Ni, and Si, respectively. Then the interactions between CO 2 and pristine or doped kaolinites (0 0 1) were systematically investigated by the analysis of the adsorption energy (E ads), electron transferring and the density of states. Finally, Pearson correlation analysis reveal that the effects of the surface hydroxyl groups of kaolinite and the atomic radius of the doping atoms are the key factors in the kaolinites-CO 2 interactions. [ABSTRACT FROM AUTHOR]

• The effects of strain rates and direction on the electronic structures of phosphorene have been studied by the density functional theory. • The regulating effect of phosphorene strain on the adsorption behavior of NO 2 , NO, CO, CO 2 and NH 3 were systematically studied. • The adsorption energy of NO 2 on phosphorene is very sensitive to the strain, especially the compressive strain. Controllable sensitivity of the surface chemical adsorption to toxic gases is important for the next generation gas sensors. Two dimensional (2D) layered nanomaterials are the excellent candidates to sensitively detect the chemical species by tuning the properties of the materials. Recently, the single and multi-layer black phosphorous (phosphorene) were discovered to exhibit better performances than graphene in the applications of field effect transistors, PN junctions, and photodetectors, and they are also ultrasensitive to the chemical gases. In this study, by using first principle calculations, we report that the adsorption of NO 2 on strained monolayer phosphorene can be noticeably enhanced, while the electronic properties of monolayer phosphorene can be apparently adjusted. The monolayer phosphorene exhibits the superior selective adsorption for NO 2 over NO, NH 3 , CO and CO 2. The compressive strains were demonstrated to be able to effectively adjust the adsorptions of NO 2. Our findings provide critical information for the novel design of phosphorene-based highly sensitive nanoscale sensors and electromechanical devices. [ABSTRACT FROM AUTHOR]