Regulating the frontier orbital of iron phthalocyanine with nitrogen doped carbon nanosheets for improving oxygen reduction activity.

Iron phthalocyanine (FePc) has attracted widespread attention for its tunable electronic structure. However, the Fe-N sites suffer from undesirable oxygen reduction activity due to the symmetric geometries. A suitable substrate was thus needed to induce electron redistribution around Fe-N to improve the activity.

Theoretical investigation of synergistically boosting the anchoring and electrochemical performance of lithiophilic/sulfiphilic transition metal carbides for lithium-sulfur batteries.

Lithium-sulfur (Li-S) battery is one of the most promising next-generation energy-storage systems with a high energy density and low cost. However, their commercial applications face several challenges, such as the shuttle effect caused by the soluble lithium polysulfide (LiPSs) intermediates and the sluggish sulfur redox reaction. In this article, we systematically investigated the anchoring and electrochemical performance of a series of transition metal carbides (TMCs: TiC, VC, ZrC, NbC, HfC, TaC) as cathode materials for Li-S batteries by theoretical calculations.

Construction of CoS Nanoparticles Embedding in N-Doped Amorphous Carbon@Graphene with Enhanced Li-Ion Storage.

Cobalt sulfide is deemed a promising anode material, owing to its high theoretical capacity (630 mAh g). Due to its low conductivity, fast energy decay, and the huge volume change during the lithiation process limits its practical application. In this work, a simple and large-scale method are developed to prepare CoS nanoparticles embedding in N-doped carbon/graphene (CSCG).

Theoretical identification of the superior anchoring effect and electrochemical performance of TiCS by single atom Zn doping for lithium-sulfur batteries.

As one of the promising next-generation energy storage systems, lithium-sulfur (Li-S) batteries have been the subject of much recent attention. However, the polysulfide shuttle effect remains problematic owing to the dissolution of intermediate polysulfide species in the electrolyte and the sluggish reaction dynamics in Li-S batteries. To overcome these issues, this work reports an effective strategy for enhancing the electrochemical performance of Li-S batteries using single atom Zn doping on the S-terminated TiC MXenes (TiZnCS).

Urchin-like band-matched FeO@InS hybrid as an efficient photocatalyst for CO reduction.

Herein, an urchin-like FeO@InS hybrid composite is designed and synthesized using a facile process. The composite efficiently harvests light in both the ultraviolet and visible regions, and the unique hierarchical structure provides several advantages for photocatalytic applications: (i) a suitable band-matching structure and broadband-light absorbing capacity enable the reduction of CO into hydrocarbon, (ii) the extensive network of interfacial contact between nano-sized FeO and InS significantly increases the separation of charge carriers and enhances the utilization of photogenerated electron-hole pairs, and (iii) an abundance of surface oxygen vacancies provide numerous active sites for CO molecule adsorption. The optimized FeO@InS composite generated CO from the photocatalytic reduction of CO at a rate of 42.

Synthesis of CoP@B,N,P co-doped porous carbon by a supramolecular gel self-assembly method for lithium-sulfur battery separator modification.

Lithium-sulfur batteries (LSBs) are regarded as promising next-generation batteries due to their high abundance and high theoretical energy density. However, the commercial application of LSBs is hindered by the shuttle effect of soluble lithium polysulfides (LiPSs). Hence, we synthesised B, N, P co-doped three-dimensional hierarchical porous carbon materials, uniformly dispersed with CoP nanoparticles, and utilized them as the coating material for the PE separator.

Ultrafast Kinetics in a PAN/MgFeO Flexible Free-Standing Anode Induced by Heterojunction and Oxygen Vacancies.

Flexibility and power density are key factors restricting the development of flexible lithium-ion batteries (FLIBs). Interface and defect engineering can modify the intrinsic ion/electron kinetics by regulating the electronic structure. Herein, a polyacrylonitrile/MgFeO (PAN-MFO) electrode with heterojunction and oxygen vacancies was first designed and synthesized as a flexible free-standing anode of FLIBs by electrostatic spinning technology.

Fundamental understanding of electrocatalysis over layered double hydroxides from the aspects of crystal and electronic structures.

Layered double hydroxides (LDHs) composed of octahedral ligand units centered with various transition metal atoms display unique electronic structures and thus attract significant attention in the field of electrocatalytic oxygen evolution reactions (OER). Intensive experimental explorations have therefore been carried out to investigate the LDHs synthesis, amorphous control, intrinsic material modifications, interfacing with other phases, strain, . There is still the need for a fundamental understanding of the structure-property relations, which could hinder the design of the next generation of the LDHs catalysts.

Au Species Boost the Catalytic Performance of Au/ZnO for the Semi-hydrogenation of Acetylene.

Au nanoparticles have garnered remarkable attention in the chemoselective hydrogenation due to their extraordinary selectivity. However, the activity is far from satisfactory. Knowledge of the structure-performance relationship is a key prerequisite for rational designing of highly efficient Au-based hydrogenation catalysts.

Cooperative Catalysis toward Oxygen Reduction Reaction under Dual Coordination Environments on Intrinsic AMnO -Type Perovskites via Regulating Stacking Configurations of Coordination Units.

It remains challenging for pure-phase catalysts to achieve high performance during the electrochemical oxygen reduction reaction to overcome the sluggish kinetics without the assistance of extrinsic conditions. Herein, a series of pristine perovskites, i.e.

Tuning the ORR activity of Pt-based TiCO MXenes by varying the atomic cluster size and doping with metals.

The rational design of ideal catalysts for the oxygen reduction reaction (ORR) is of great significance for solving the electrocatalytic potential problems in proton exchange membrane fuel cells (PEMFCs). Pt (n = 1-4) and PtAu alloy subnanoclusters supported on a defective TiCO monolayer with oxygen vacancies (denoted as v-TiCO) are simulated by using density functional theory to investigate their ORR performance. The geometries, energetics, and electronic properties of the different systems are analyzed.

Tailoring the Electronic Structure of Transition Metals by the VC MXene Support: Excellent Oxygen Reduction Performance Triggered by Metal-Support Interactions.

The enhancement of oxygen reduction reaction (ORR) activity can significantly boost the performance of fuel cells. MXene-supported transition metals with strong metal-support interactions (SMSI) are an effective strategy to increase the catalytic activity and durability while decreasing the usage of noble metals. Herein, a series of composites of transition-metal atoms (Ni, Pd, Pt, Cu, Ag, and Au) deposited on VC MXene are designed as potential catalysts for ORR using density functional theory.

Efficient metal overlayer catalysts on the NbC monolayer for CO oxidation from first-principles screening.

Based on the first-principles calculation, the configurations of different metal overlayers on the monolayer NbC (MXene) (M/NbC) (M  =  Rh, Ir, Pd, Pt, Ag, Au) were studied aiming to find a kind of complex system with high CO-tolerance and high CO conversion efficiency. Combined with the stability of the composite systems and their adsorption properties on small gas molecules, Ag/NbC was screened out and further tested for CO oxidation reaction. By comparing the energy barriers of different reaction pathways, we concluded that CO oxidation reaction could be carried out on Ag/NbC var the LH mechanism with a small energy barrier of 0.

Surface vacancy on PtTe for promoting CO oxidation through efficiently activating O.

Platinum group metal dichalcogenides (PtTe) with controllable thickness have been synthesized and confirmed to be promising electric and spintronic materials. Here, using the first-principles calculations, we demonstrate the potential application of PtTe as catalyst substrate. Taking CO oxidation as model reaction, the importance of surface vacancy is clarified.

An electronic perturbation in TiC supported platinum monolayer catalyst for enhancing water-gas shift performance: DFT study.

The water-gas shift (WGS) reaction behaviors over the TiC(0 0 1) supported Pt monolayer catalyst (Pt/TiC(0 0 1)) are investigated by using the spin-unrestricted density functional theory calculations. Importantly, we find that the Pt/TiC(0 0 1) system exhibits a much lower density of Pt-5d states nearby the Fermi level compared with that for Pt(1 1 1), and the monolayer Pt atoms undergo an electronic perturbation when in contact with TiC(0 0 1) support that would strongly improve the WGS activity of supported Pt atoms. Our calculations clearly indicate that the dominant reaction path follows a carboxyl mechanism involving a key COOH intermediate, rather than the common redox mechanism.

Low-temperature preferential oxidation of CO over Ag monolayer decorated MoC (MXene) for purifying H.

Selective removal of CO from reformate streams at low temperature is an important issue to be solved for anode catalysts of proton exchange membrane fuel cells (PEMFCs). Using density functional theory, we demonstrate that the Ag monolayer decorated MoC can be used as an effective low cost catalyst with high activity, selectivity and stability for preferential oxidation of CO. Ag monolayer decorated MoC can also be used as a filter membrane for separating H and CO.

Tunable Electric Properties of Bilayer α-GeTe with Different Interlayer Distances and External Electric Fields.

Based on first-principle calculations, the stability, electronic structure, optical absorption, and modulated electronic properties by different interlayer distances or by external electric fields of bilayer α-GeTe are systemically investigated. Results show that van der Waals (vdW) bilayer α-GeTe has an indirect band structure with the gap value of 0.610 eV, and α-GeTe has attractively efficient light harvesting.

A Simple Wireless Sensor Node System for Electricity Monitoring Applications: Design, Integration, and Testing with Different Piezoelectric Energy Harvesters.

Real time electricity monitoring is critical to enable intelligent and customized energy management for users in residential, educational, and commercial buildings. This paper presents the design, integration, and testing of a simple, self-contained, low-power, non-invasive system at low cost applicable for such purpose. The system is powered by piezoelectric energy harvesters (EHs) based on PZT and includes a microcontroller unit (MCU) and a central hub.

Strong metal-support interactions impart activity in the oxygen reduction reaction: Au monolayer on MoC (MXene).

The rational design of low-cost, high-efficiency, corrosion-resistant and persistent-activity oxygen reduction reaction (ORR) electrocatalysts is a common goal for the large-scale application of fuel cells. Inspired by the excellent characteristics of MXenes when used as substrate materials and recent experiments of depositing metal nanoparticles on MXenes, we systematically investigated monolayer metal thin films decorated by MoC (MXene) (M/MoC, M  =  Cu, Pd, Pt, Ag and Au) as ORR catalysts using density functional theory. According to the stability and adsorption properties, we speculate that Au/MoC possesses outstanding ORR performance and enhanced durability in comparison with Pt/C catalysts.

Cu-Cluster-Doped Monolayer MoCO (MXene) as an Electron Reservoir for Catalyzing a CO Oxidation Reaction.

The catalytic oxidation of CO on Cu-cluster-decorated pristine and defective MoCO (MXene) monolayers (Cu/p-MoCO and Cu/d-MoCO) was investigated by first-principles calculations. The stability of the designed catalysts was comprehensively demonstrated via analysis of the energies, geometry distortion, and molecular dynamics simulations at finite temperatures. The difference in the individual adsorption energies, as well as the oxidation and poisoning of Cu/p(d)-MoCO under CO and O gas atmospheres, was tested to estimate the catalytic ability.

TiC and TiN supported platinum monolayer as high-performance catalysts for CO oxidation: A DFT study.

The reactivity toward CO oxidation of Pt monolayer supported on TiC(001) and TiN(001) is studied by using empirical dispersion-corrected density functional theory calculations. A number of possible reaction pathways for CO oxidation, including the Eley-Rideal (ER) and Langmuir-Hinshelwood (LH) mechanisms, between adsorbed O and CO molecules considering the cases that the adsorbed O dissociates first or directly reacts with CO. It is found that the dissociation adsorption of O molecules as the initial step is more favorable with lower activation barriers compared with the direct reaction mode.

Repairing single and double atomic vacancies in a CN monolayer with CO or NO molecules: a first-principles study.

Even the simplest point defect in a two-dimensional (2D) material can have a significant influence on its electronic, magnetic, and chemical properties. Defect repairing in 2D materials has been a focus of concern in recent years. Based on first-principles calculations, the repair of C and N single vacancies with CO or NO molecules in a C3N monolayer has been studied.

Density functional study on the high catalytic performance of single metal atoms on the NbC(001) surface.

The adsorption and activation of O2 is regarded as the first critical step for the oxygen reduction reaction (ORR), and catalysts with a high performance toward O2 adsorption and activation would provide a theoretical foundation for further investigations. Here, we have studied the adsorption and electronic properties as well as the catalytic activities of group 9-11 single metal atoms deposited on NbC(001), denoted M/NbC(001). According to the location of the d-band centers and the frontier molecular orbital analysis, single metals of Co, Rh, Ir and Ni on NbC(001) exhibit higher activities than other metals (Pd, Pt, Cu, Ag and Au).

A Au monolayer on WC(0001) with unexpected high activity towards CO oxidation.

Catalysts with weak adsorption yet high reactivity towards CO are urgently required to solve the serious problem of CO poisoning that occurs in many important reactions, e.g., in fuel cells.

Single Pd atomic catalyst on MoCO monolayer (MXene): unusual activity for CO oxidation by trimolecular Eley-Rideal mechanism.

The geometric stability, electronic structure and catalytic properties of a single Pd atom deposited on a pristine MoCO monolayer and a defective MoCO monolayer with an oxygen vacancy (denoted as Pd/O-MoCO) are systematically investigated through density functional theory. We find that the oxygen vacancy (O) can stabilize the single Pd atom and make the Pd/O-MoCO system an excellent mono-dispersed atomic catalyst. The Pd dopant serves as an active center which makes the intermediates react productively around it.