Adjacent Atoms Research Articles

Boosting capacitive performance of nitrogen-doped carbon by atomically dispersed iron

Carbon-based electrochemical capacitors are important energy storage devices owing to their high power and long life. However, their practical implementation has been restrained by low energy as a result of the limitation of double-layer capacitance. In this work, we demonstrate that the incorporation of atomically dispersed Fe into nitrogen-doped carbon (Fe−NC) can drastically boost the double-layer capacitance of carbon materials. Electrochemical tests reveal that an enhancement in the capacitance from 147.5 F g−1 to 174.8 F g−1 is realized when single Fe atoms are incorporated into nitrogen-doped carbon. In addition, symmetric supercapacitors based on Fe−NC exhibit a robust cycling performance, retaining 94.7% of the capacitance over 100,000 cycles. This improvement can be correlated to the chemical coordination of iron with adjacent nitrogen atoms to tailor the electric structure of carbon, which increases the density of states near the Fermi level and improves anion adsorption on atomic Fe sites. The single-atom engineering strategy may offer new possibilities to develop high-performance carbon materials for capacitors.

Boosting the efficiency of Fe-MoS2/peroxymonosulfate catalytic systems for organic powllutants remediation: Insights into edge-site atomic coordination

Fe atoms were highly isolated by the edge Mo vacancies and the adjacent Mo atoms could provide electrons smoothly for the regeneration of Fe(II). • Fe-MoS 2 catalyst with Fe atomically anchored at the edge Mo vacancies was prepared. • Fe(II) can be rapidly regenerated through the Mo-S 2 -Fe-S 2 -Mo edge configuration. • The electron transfer between edge Mo, S and Fe atoms were well clarified. • Both the adsorption and activation of PMS were systemically investigated. • Fe-MoS 2 was highly stable for the AOPs of varied persistent organic pollutants. Here, we designed and prepared edge defect-rich Fe-MoS 2 nanohybrid catalysts via a facile post-confined strategy, in which single Fe atoms were isolated by the newly formed edge Mo vacancies. Evaluation of the decontamination efficiency, using the model herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), showed that the rate constant for the Fe-MoS 2 /peroxymonosulfate (PMS)/2,4-D system was (0.2777 min −1 ), seven times higher than that of a Fe-MoS 2 nanocluster counterpart (0.0323 min −1 ). The unique Mo-S 2 -Fe-S 2 -Mo edge configuration of Fe-MoS 2 promoted the regeneration of active sites during the activation reaction in which Fe(III) was reduced to Fe(II), Mo(IV) was oxidized to Mo(V), and the adjacent S atoms acted as bridges for electron transfer. Thus, PMS could be constantly activated by low valence Fe atoms resulting in superior catalytic performance. Quenching experiments and Electron Paramagnetic Resonance (EPR) signals indicated that hydroxyl radicals, sulfate radicals (SO 4 •- ), superoxide anion radicals and singlet oxygen ( 1 O 2 ) were all involved in the oxidative degradation of 2,4-D, in which 1 O 2 and SO 4 •- predominated. In addition, PMS adsorption and its activation were identified as key steps in the process, and the Fe-MoS 2 /PMS system demonstrated good robustness during continuous operation. This study provides new insights into the Fe-MoS 2 edge coordination mechanism for the PMS activated decontamination of organic pollutants.

Synergistic phosphorized NiFeCo and MXene interaction inspired the formation of high-valence metal sites for efficient oxygen evolution

Exploring low-cost, high-performance, and stable electrocatalysts toward the oxygen evolution reaction (OER) is highly desired but remains challenging. Transition metal hydroxide has been wildly utilized as a promising candidate, but practical implementation is impeded by insufficient catalytic activity, easy agglomeration, and poor conductivity. Here, we report that both phosphorization and combination with MXnene can improve the catalysts’ intrinsic activity and conductivity. Besides, MXene also prevents the agglomeration of the nanoparticles, resulting in the enhanced exposure of active sites. Experimental characterizing and density functional theory simulations revealed that P species can attract electrons to promote the formation of high-valence states of adjacent metal atoms, and coupling MXene support can effectively modulate the electronic structure and optimize the d-band center, which boosts the OER performance. Consequently, the optimized NiFeCoP/Mxene catalyst exhibits a low overpotential of 240 mV at a current density of 10 mA cm−2, a small Tafel slope of 55 mV dec−1, and superior long-term stability of 40 h in 1 M KOH electrolyte, which is superior to other counterparts.

Hydrazine Hydrate Intercalated 1T-Dominant MoS2 with Superior Ambient Stability for Highly Efficient Electrocatalytic Applications.

Metallic 1T-phase MoS2 exhibits superior hydrogen evolution reaction (HER) performance than natural 2H-phase MoS2 owing to its higher electrical conductivity and abundance of active sites. However, the reported 1T-MoS2 catalysts usually suffer from extreme instability, which results in quick phase transformation at ambient conditions. Herein, we present a facile approach to engineer the phase of MoS2 by introducing intercalated hydrazine. Interestingly, the as-synthesized 1T-dominant MoS2 sample demonstrates excellent ambient stability without noticeable degradation for 3 months. Additionally, the 1T-dominant MoS2 exhibits superior electrical conductivity (∼700 times higher than that of 2H-MoS2) and improved electrochemical catalytic performance (current density ∼12 times larger than that of 2H-MoS2 at an overpotential of 300 mV vs the reversible hydrogen electrode, RHE). Through experimental characterizations and density functional theory (DFT) calculation, we conclude that the stabilization of the metallic phase could be attributed to the electron donation from hydrazine molecules to the adjacent Mo atoms. The phase control strategy in this work provides a guideline to develop other highly efficient and stable two-dimensional (2D) electrocatalysts.

Unraveling the role of active hydrogen caused by carbonyl groups in surface-defect passivation of perovskite photovoltaics

The molecules with carbonyl group are regarded as ideal candidates to passivate surface-defects on metal halide perovskites. However, as an electron-withdrawing group, the CO groups are the ones that make hydrogen active on their adjacent atoms. Therefore, carbonyl compounds tend to produce keto-enol tautomerism and dissociation of hydrogen, which would affect their passivation effect. Herein, we chose three carbonyl-based molecules, morpholine, 3-morpholone and 3,5-morpholone with different amounts of carbonyl groups, to systematically investigate the effect of active hydrogen on their defect-passivation effect. The passivation effect of multifunctional molecule would be maximized when the molecule was in an optimal configuration with negligible active hydrogen. Consequently, a champion power conversion efficiency of 23.05% was approached with 3-morpholone surface treatment. The finding in this work reveals the importance of carbonyl distribution in molecular configuration when designing multifunctional passivation molecules in perovskite photovoltaics.

First-Principles Study of Electronic Properties of Substitutionally Doped Monolayer SnP3.

SnP3 has a great prospect in electronic and thermoelectric device applications due to its moderate band gap, high carrier mobility, absorption coefficients, and dynamical and chemical stability. Doping in two-dimensional semiconductors is likely to display various anomalous behaviors when compared to doping in bulk semiconductors due to the significant electron confinement effect. By introducing foreign atoms from group III to VI, we can successfully modify the electronic properties of two-dimensional SnP3. The interaction mechanism between the dopants and atoms nearby is also different from the type of doped atom. Both Sn7BP24 and Sn7NP24 systems are indirect bandgap semiconductors, while the Sn7AlP24, Sn7GaP24, Sn7PP24, and Sn7AsP24 systems are metallic due to the contribution of doped atoms intersecting the Fermi level. For all substitutionally doped 2D SnP3 systems considered here, all metallic systems are nonmagnetic states. In addition, monolayer Sn7XP24 and Sn8P23Y may have long-range and local magnetic moments, respectively, because of the degree of hybridization between the dopant and its adjacent atoms. The results complement theoretical knowledge and reveal prospective applications of SnP3-based electrical nanodevices for the future.

Carbon-rehybridization-induced templated growth of metal nanoclusters on graphene moiré patterns

Templated growth of monodisperse metal nanoclusters has successfully been realized through graphene moiré patterns on transition metal substrates, but the underlying mechanism is still unclear. Herein, based on first-principles calculations, we systematically study the growth mechanism of Pt and Au nanoclusters on graphene-covered Ir(111) substrate. Our results indicate that the induced sp2-sp3 rehybridization of C atoms plays a key role for the templated growth. From the center of the template to the outside, such rehybridization is gradually suppressed due to the enlarged horizontal distance between C atoms and the adjacent Ir atoms, which causes weaker bonding of Pt atoms to larger clusters and thus the perfect templated growth. Meanwhile, negligible sp2-sp3 rehybridization is observed due to the weak adsorption of Au atoms on graphene, which leads to the failure of the template. This mechanism is then extended to other metal nanoclusters successfully. We believe that it will help to understand the structure-activity relationship of more two-dimensional templates.

Enhanced oxygen reduction with carbon-polyhedron-supported discrete cobalt-nitrogen sites for Zn-air batteries

• A general strategy to construct discrete Co-N 4 sites confined in carbon polyhedron. • Porous carbon polyhedron with bumpy exterior boosts the exposure of active sites. • Zn acts as sacrificed “shield” to isolate the adjacent Co atoms from aggregating. • Co-N/ZIF-2 catalyst shows high ORR activity superior to commercial Pt/C. • Zn-air battery exhibits high power density of 260 mW cm −2 and stability in 200 h. The specific structure of metal atoms including coordination environment and dispersibility, together with carbon support architecture in metal-nitrogen-carbon (M−N−C) materials are of great importance for their capabilities to catalyze oxygen reduction reaction (ORR). Herein, we report a novel strategy to achieve highly exposed and atomically isolated Co-N 4 active sites within porous carbon polyhedron with bumpy exterior by pyrolysis of predesigned Zn-modified metal–organic frameworks (MOFs) together with tripolycyanmide, during which Zn is evaporated away at high temperature of 900 °C and leaves free vacancies for N to stabilize Co atoms. The bumpy exterior dramatically enlarges its specific surface area and improves the number of active sites. The local structure of single Co atoms coordinated with N is confirmed by combing spherical aberration correction electron microscopy and X-ray absorption fine structure analyses. Remarkably, the obtained Co-N 4 single sites exhibit a high ORR activity with a half-wave potential of 0.861 V that is superior to commercial Pt/C (0.819 V), as well as excellent performance and stability in Zn-air batteries with a peak power density of 260 mW cm −2 . Our work will endow the opportunities to propagate this approach to develop various single-metal-atom materials.

Enhanced thermoelectric performance by lone-pair electrons and bond anharmonicity in the two-dimensional Ge2Y2 family of materials with Y=N , P, As, or Sb

Using density functional theory combined with the Boltzmann transport equation, the charge, thermal transport, and thermoelectric properties in two-dimensional (2D) ${\mathrm{Ge}}_{2}{Y}_{2}$ ($Y=\text{N}$, P, As, or Sb) monolayers characterized by two structural phases, i.e., $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Ge}}_{2}{\mathrm{Y}}_{2}$ and $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Ge}}_{2}{\mathrm{Y}}_{2}$, have been studied systematically. Our theoretical results demonstrate that the lone-pair electrons have remarkable influences on their lattice thermal conductivity. By performing comparative studies on the two different structures of ${\mathrm{Ge}}_{2}{\mathrm{Sb}}_{2}$, we uncover that the above influences not only originate from the interactions between the lone-pair electrons around Sb atoms and the bonding electrons of the adjacent Ge atom, but also from the interlayer Coulomb repulsive forces of lone-pair electrons distributed in different layers. The latter leads to a strong anharmonicity, which greatly suppresses the lattice thermal conductivity. Thus, $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Ge}}_{2}{\mathrm{Sb}}_{2}$ monolayer has an ultralow thermal conductivity with 0.19 W/mK, while $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Ge}}_{2}{\mathrm{Sb}}_{2}$ monolayer with 5.1 W/mK at the temperature 300 K. Owing to the ultralow lattice thermal conductivity induced by lone-pair electrons, the predicted maximum value of the thermoelectric figure of merit ($ZT$) reaches 1.2 for $p$-type and 1.18 for $n$-type doping $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Ge}}_{2}{\mathrm{Sb}}_{2}$. Our theoretical results put forward another effective mechanism to design and optimize 2D thermoelectric materials with high thermoelectric conversion efficiency.

Rational design ternary platinum based electrocatalysts for effective methanol oxidation reaction

Exploring effective, durable, and affordable electrocatalysts of methanol oxidation reaction (MOR) is of vital significance for the industrial application of direct methanol fuel cells. Herein, an efficient, general, and expandable method is developed to synthesis two-dimensional (2D) ternary PtBiM nanoplates (NPLs), in which various M (Co, Ni, Cu, Zn, Sn) is severed as the third component to the binary PtBi system. The MOR performance of PtBiM NPLs is entirely investigated, demonstrating that both the MOR activity and durability is enhanced with the introduction of the additional composition. Pt3Bi3Zn NPLs shows much higher MOR activity and stability than that of the PtBi counterparts, not to mention the current advanced PtRu/C and Pt/C catalysts. The prominent performances are attributed to the modulated electronic structure of the surface Pt in PtBi NPLs by the addition of Zn, resulting in a weakened affination between Pt and the adsorbed poisoning species (mainly CO) compared with PtBi NPLs, verified by density functional theory (DFT) calculations. In addition, the absorbed OH can be generated on the surface of Zn atom due to its favorable water activation properties, thus the CO removal on the adjacent Pt atoms is accelerated, further leading to a high activity and anti-poisoning performance of the resulting Pt3Bi3Zn catalyst. This work provides new insights and robust strategy for highly efficient MOR electrocatalyst with extraordinary anti-poisoning performance and stability.

Modulating Chemical Environments of Metal-Organic Framework-Supported Molybdenum(VI) Catalysts for Insights into the Structure-Activity Relationship in Cyclohexene Epoxidation.

Solid supports are crucial in heterogeneous catalysis due to their profound effects on catalytic activity and selectivity. However, elucidating the specific effects arising from such supports remains challenging. We selected a series of metal-organic frameworks (MOFs) with 8-connected Zr6 nodes as supports to deposit molybdenum(VI) onto to study the effects of pore environment and topology on the resulting Mo-supported catalysts. As characterized by X-ray absorption spectroscopy (XAS) and single-crystal X-ray diffraction (SCXRD), we modulated the chemical environments of the deposited Mo species. For Mo-NU-1000, the Mo species monodentately bound to the Zr6 nodes were anchored in the microporous c-pore, but for Mo-NU-1008 they were bound in the mesopore of Mo-NU-1008. Both monodentate and bidentate modes were found in the mesopore of Mo-NU-1200. Cyclohexene epoxidation with H2O2 was probed to evaluate the support effect on catalytic activity and to unveil the resulting structure-activity relationships. SCXRD and XAS studies demonstrated the atomically precise structural differences of the Mo binding motifs over the course of cyclohexene epoxidation. No apparent structural change was observed for Mo-NU-1000, whereas the monodentate mode of Mo species in Mo-NU-1008 and the monodentate and bidentate Mo species in Mo-NU-1200 evolved to a new bidentate mode bound between two adjacent oxygen atoms from the Zr6 node. This work demonstrates the great advantage of using MOF supports for constructing heterogeneous catalysts with modulated chemical environments of an active species and elucidating structure-activity relationships in the resulting reactions.

Weakening O[sbnd]O binding on Au-Cu2O/carbon nanotube catalysts with local misfit dislocation by interfacial coupling interaction for oxygen reduction reaction

Au-incorporation into nonprecious metal oxides is a promising strategy to optimize the constitution and improve electron transfer at the interface. Regrettably, achieving the desired performances has remained a significant challenge in oxygen reduction reaction (ORR). Here, we report the synthesis of the xAu-Cu2O/carbon nanotube (CNTs) catalysts. In the case of 0.52Au-Cu2O/CNTs, the Au atoms are incorporated into the Cu2O lattice and an atomically dispersed Au is distributed on the outer shell regions of Cu2O microsphere, and it exhibits a superior ORR activity among the as-prepared catalysts due to strong interfacial coupling interaction. Density functional theory (DFT) calculations reveal that the adsorption of O2 on Au-Cu2O is the bridge mode between Cu and adjacent Au atoms, which can accelerate the kinetics of the OO bond split and increase the dissociation of OO bonds. The study evidences the significant role of interfacial coupling interaction in binary or multi-component electrocatalysts.

Synthesis of Uranium Single Atom from Radioactive Wastewater for Enhanced Water Dissociation and Hydrogen Evolution.

As a common nuclide in radioactive wastewater, uranium (U) is generally treated by landfill, which induces the massive abandonment of uranium resources. In this work, a pulse voltammetry method for the synthesis of U single atoms on MoS2 (U/MoS2 ) nanosheets from radioactive wastewater for the electrocatalytic alkaline hydrogen evolution reaction (HER) is reported. The mass loading of U single atoms is facilely controlled with high selectivity for coexisting ions in radioactive wastewater. In the electrolyte of 1 m of KOH, U/MoS2 nanosheets with 5.2% of U single atoms exhibit relatively low overpotentials of 72 mV at 10 mA cm-2 . The mechanistic study reveals that the HER on U/MoS2 includes the water dissociation on U single atoms to form OH* and H transfer from OH* to adjacent S-edge atoms. This procedure exhibits decreased activation energy for transition state in water dissociation and optimized Gibbs free energy for H* adsorption.

Study of the core-shell structure MoSi2@ Al2O3 powder prepared by the sol-gel method in a low-vacuum atmosphere

Molybdenum disilicide (MoSi 2 ) is a novel crack-healing material used in the traditional thermal barrier coating , which reacts with ZrO 2 to attain a corresponding volume expansion of approximately 138%. However, the pre-oxidation of MoSi 2 causes the “pesting” phenomenon, which degrades the microstructure and mechanical properties throughout the service. To address this issue, the aluminum oxide was fabricated on the MoSi 2 surface using the sol-gel method and low-pressure post-heat treatment to prevent oxygen penetration. The orthogonal experiment investigated the effect of pH, temperature, and water amount on sol generation. Because the Zeta potential difference has reached its maximum value (about 27 mV) at pH 4, the aluminum sol was notably adsorbed on the MoSi 2 particles. The modified MoSi 2 @Al 2 O 3 particles were characterized to understand their morphologies, surface adsorption energy, and crystal structures. The oxygen adsorption energy on the MoSi 2 (103) surface was lower than that on the Mo 5 Si 3 (411) surface, which indicated that the oxidization process can be divided into two independent steps. The Al 2 O 3 shell was uniformly formed on the MoSi 2 particles, especially in the low-vacuum environment (10 MPa) for 3 h post-treatment. The dense core-shell structure can prevent oxygen penetration into the MoSi 2 surface, thus prolonging the self-healing property of MoSi 2 . • Heterogeneous charge between MoSi 2 and C 9 H 21 AlO 3 is maximum at pH 4.0. • “Pesting” phenomenon occurs by the preferential oxidization of adjacent Mo atoms. • MoSi 2 @Al 2 O 3 core-shell structure is uniformly generated in a low-vacuum atmosphere. • MoSi 2 @Al 2 O 3 can prevent oxygen from reacting with the MoSi 2 surface.

Tuning the Electronic Properties of Main-Group Species by N-Heterocyclic Vinyl (NHV) Scaffolds

ConspectusMolecules and materials with easily tunable electronic structures and properties are at the forefront of contemporary research. π-Conjugation is fundamental in organic chemistry and plays a key role in the design of molecular materials. In this Account, we showcase the applicability of N-heterocyclic vinyl (NHV) substituents based on classical N-heterocyclic carbenes (NHCs) for tuning the structure, properties, and stability of main-group species (E) via π-conjugation and/or π-donation.NHVs such as [(NHC)═CR] (R = H or aryl) are monoanionic ligands formally derived by the deprotonation of N-heterocyclic olefins (NHOs), (NHC)═CHR. Further deprotonation of [(NHC)═CR] (R = H) is viable, giving rise to N-heterocyclic vinylidene (NHVD) species such as (NHC)═C. NHVs and NHVDs feature a highly polarizable exocyclic CNHC═C bond because of the presence of adjacent π-donor nitrogen atoms. The nature of the NHC, in particular the π-acceptor property, has a direct consequence on the polarity of the CNHC═C bond and hence on the magnitude of π-conjugation in the derived molecules. Thus, the electronic structure, especially the energy and shape of frontier molecular orbitals, HOMO and LUMO, of derived species can be fine-tuned by a judicious choice of the carbene unit. For instance, the HOMO of classical diphosphenes (RP═PR) (R = alkyl or aryl) is invariably the phosphorus lone-pair orbital, while the P═P π-bond is HOMO - 1 or HOMO - 2. In strong contrast, the HOMO of divinyldiphosphenes (R = NHV) is mainly the P═P π-bond. This is owing to the π-conjugation, resulting in the lowering of the LUMO and raising of the HOMO energy. They have a remarkably small HOMO-LUMO energy gap (4.15-4.50 eV) and readily undergo 1e-oxidations, giving rise to stable radical cations and dications.By employing a similar approach, one can access divinyldiarsenes and the corresponding radical cations and dications as crystalline solids. The use of divinyldiphosphenes and divinyldiarsenes as promising ligands in the stabilization of metalloradicals has been shown. By a logical selection of singlet carbenes, stable 2-phosha-1,3-butadiene and 2-arsa-1,3-butadiene compounds, as well as related radical cations and dications, can be prepared as crystalline solids.The relevance of NHV ligands as potent π-donors has been demonstrated for the stabilization of elusive electrophilic phosphinidene and arsinidene complexes {(NHV)E}Fe(CO)4 (E = P or As). Moreover, stable singlet diradicaloid [(NHC)CP]2 and p-quinodimethane derivatives [(NHC)CP2]2 based on an NHVD framework are accessible as stable solids.In this Account, a special emphasis is given to the contributions from this laboratory. The author hopes that this Account will serve as a useful reference guide for researchers interested in studying and applying NHV and NHVD scaffolds in modern molecular chemistry and materials sciences.

A new explanation on valence electron structure of C, Si, and Ge crystals with diamond structure based on photoelectron spectra

According to the classical covalent-bond (CVB) model, the two s and two p valence electrons in C, Si, and Ge crystals with diamond structure adopt an equivalent sp3 structure and form four covalent bonds between an atom and its four adjacent atoms. Therefore, the four valence electrons (sp3) per atom should have the same energy state. However, many experimental results indicate that the valence electrons of these element crystals have different binding energies. Therefore, in this paper, we propose a local valence electron (LVE) model for these materials, on the basis of valence electron spectra for the C, Si, and Ge crystals: The states of the four valence electrons per atom in these crystals are similar to those in the free atoms (s2p2), except that the shape of their outer electron cloud shells deviates from the ball shell distribution in the crystals, forming positive ions and equivalent-negative- electrical-charge centers. One of the important reasons why all the valence electrons of diamond are local electrons is that free C atom has high first ionization energy, 11.26 eV, being much higher than those of all the metal atoms. This LVE model is accordance with that diamond has wide energy gap (5.4 eV) in the energy band theory, which forbids electron transition from the filled valence band to the vacant conduction band.

Oxidation behavior of layered FenGeTe2 (n = 3, 4, 5) and Cr2Ge2Te6 governed by interlayer coupling.

Layered magnetic materials have recently received tremendous attention due to an attractive combination of functional properties suitable for nanoelectronics and spintronic applications. Enhancing the air stability of the material is a prerequisite for long-term durability of devices. However, the oxidation mechanism of layered magnetic materials is yet to be revealed. Herein we explore the oxidation behavior of monolayer and multilayer FenGeTe2 (n = 3, 4, 5) and Cr2Ge2Te6 using first-principles calculations. The results show that these monolayer systems are prone to be oxidized in ambient air. With increasing thickness, however, multilayer FenGeTe2 exhibits distinct oxidation behavior from its monolayer counterparts, originating from its unexpected strong interlayer coupling characterized by wavefunction overlapping of adjacent Te atoms between FenGeTe2 layers. Moreover, O2 adsorption does not severely deteriorate the magnetism of layered FenGeTe2 and Cr2Ge2Te6. Given the fact that oxidation properties can be altered by interlayer coupling, our work opens a paradigm for obtaining oxidation-resistant layered materials.

Synergistic effect of a diatomic boron-doped layered two-dimensional MSi2N4 monolayer for an efficient electrochemical nitrogen reduction

A diatomic boron-doped two-dimensional MSi2N4 monolayer (M = transition metal) can boost electrochemical N2 reduction to NH3 with high activity due to the synergistic effect of adjacent boron atoms, both thermodynamically and kinetically.

Pyrazole-containing pharmaceuticals: target, pharmacological activity, and their SAR studies.

Pyrazole is a five-membered heterocycle bearing two adjacent nitrogen atoms. Both pharmaceutical agents and natural products with pyrazole as a nucleus have exhibited a broad spectrum of biological activities. In the last few decades, more than 40 pyrazole-containing drugs have been approved by the FDA for the treatment of a broad range of clinical conditions including celecoxib (anti-inflammatory), CDPPB (antipsychotic), difenamizole (analgesic), etc. Owing to the unique physicochemical properties of the pyrazole core, pyrazole-containing drugs may exert better pharmacokinetics and pharmacological effects compared with drugs containing similar heterocyclic rings. The purpose of this paper is to provide an overview of all the existing drugs bearing a pyrazole nucleus that have been approved or in clinical trials, involving their pharmacological activities and SAR studies.

Potential of Black Phosphorus in Immune‐Based Therapeutic Strategies

Black phosphorus (BP) consists of phosphorus atoms, an essential element of bone and nucleic acid, which covalently bonds to three adjacent phosphorus atoms to form a puckered bilayer structure. With its anisotropy, band gap, biodegradability, and biocompatibility properties, BP is considered promising for cancer therapy. For example, BP under irradiation can convert near-infrared (NIR) light into heat and reactive oxygen species (ROS) to damage cancer cells, called photothermal therapy (PTT) and photodynamic therapy (PDT). Compared with PTT and PDT, the novel techniques of sonodynamic therapy (SDT) and photoacoustic therapy (PAT) exhibit amplified ROS generation and precise photoacoustic-shockwaves to enhance anticancer effect when BP receives ultrasound or NIR irradiation. Based on the prospective phototherapy, BP with irradiation can cause a “double-kill” to tumor cells, involving tumor-structure damage induced by heat, ROS, and shockwaves and a subsequent anticancer immune response induced by in situ vaccines construction in tumor site, which is referred to as photoimmunotherapy (PIT). In conclusion, BP shows promise in natural antitumor biological activity, biological imaging, drug delivery, PTT/PDT/SDT/PAT/PIT, nanovaccines, nanoadjuvants, and combination immunotherapy regimens.