Active Sites Research Articles

Integrating photochemical and photothermal effects for selective oxidative coupling of methane into C2+ hydrocarbons with multiple active sites

The direct photocatalytic oxidation of methane to value-added chemicals has garnered considerable interest in recent years. However, achieving high productivity while maintaining high selectivity at an appreciable methane conversion rate remains a formidable challenge. Here, we present photochemically-triggered and photothermally-enhanced oxidative coupling of methane to multi-carbon C2+ alkanes over an Au and CeO2 nanoparticle-decorated ZnO photocatalyst, which exhibits a record-breaking C2+ production rate of 17,260 μmol g−1 h−1 with ~90% C2+ selectivity under wide-spectrum light irradiation without a secondary source of heating. Comprehensive characterizations and computational studies reveal that CH4 activation is a photochemical reaction initiated by ultraviolet light-excited ZnO, and the introduction of CeO2 substantially enhances the activation of CH4 and O2 due to the cooperative interaction between Au and CeO2. Concurrently, Au nanoparticles capture visible and near-infrared light to generate localized heating, which greatly promotes the subsequent desorption of produced methyl radical for C–C coupling prior to undergoing further undesired overoxidation.

Spatially Coupling Electronic-Ionic Transport in Organic Mixed Conductors as Cathodes for Efficient Zn-V Batteries.

In conventional electrodes, concentration polarization by unbalanced charge transport and solid-state diffusion resistance result in sluggish reaction kinetics, hindering the practical application of zinc-ion batteries. Here, we propose an integrated mixed electronic-ionic conductor by spatially coupling charge transport pathways, which could achieve redistribution and fast transport of charge (Zn2+/e-). Operando electrochemical quartz crystal microbalance and electrochemical impedance spectroscopy revealed the charge transport mechanisms and intrinsic conducting characteristics at timescale. Through confinement by vanadium oxide, dual-conductive pathways were self-assembled at the nanoscale and provided effective charge storage. This provided high charge density and accelerated ionic diffusion in the bulk phase, resulting in more active sites and faster reaction kinetics. Moreover, reversible ionic channels from self-doping/de-doping process reduced the dissolution of active materials by protons and enabled conversion chemistry, improving cycling stability at low current density. Consequently, the modulated cathode (PEDOT-SO3-ZnVO) delivered a high-rate performance of 310/148 mAh g-1 (0.2/10 A g-1) at 10 mg cm-2. Importantly, the conventional electrode at 21 mg cm-2 achieved an ultra-high areal capacity of 6.0 mAh cm-2 and superior cycling stability (79.1% retention over 100 cycles at 0.2 A g-1). This work opens the way for the precise modulation of the electrochemical performance of functional nanomaterials.

Ag-ZnO Nanoflowers Enable Highly Selective Photocatalytic Conversion of CH4 to CH3OH at Atmospheric Pressure: Unraveling Reactive Interfaces and Intermediate Control.

At atmospheric pressure, the main challenge in the photocatalytic oxidation of CH4 to CH3OH is to absorb and activate the inert C─H bond while preventing excessive oxidation of CH3OH. In this study, metal-supported ZnO nanoflowers (Ag-ZnO) are designed to produce abundant active interfacial oxygen sites for CH4 oxidation at atmospheric pressure, with a CH3OH yield reaching 1300µmol gcat -1h-1 and the selectivity is 94%. DFT calculation and in situ analysis show that the addition of Ag regulates the electron state density and band center of O, which is beneficial to the adsorption of CH4, and decreases the dissociation energy barrier of C─H bond at OL(Lattice oxygen) site. The further selective conversion of ·CH3 to CH3OH involves two different pathways: one pathway consists of the oxidation of ·CH3 by OL, and the other pathway is the combination of ·CH3 and ·OH generated from dissolved O2 (0.28mm) in water. Notably, in the photochemical flow device, the yield of CH3OH is increased to 5200µmol gcat -1h-1 and the selectivity is close to 100%. This work offers valuable insights into reactive interfaces, morphological engineering, and the control of intermediate evolution toward selective conversion of CH4 to oxygenates at atmospheric pressure.

A bipolar-redox tetraalkynylporphyrin macrocycle positive electrode with 12-electrons-transfer for high-energy aluminum-organic batteries

Organic electrode materials with bipolar-redox activity are a promising candidate for high-energy aluminum-ion batteries (AIBs), but face the capacity ceiling due to limited active sites and low electron transfer number. To universally address this issue, seeking for a kind of multisite bipolar organic material to achieve multielectron transfer is a prerequisite but challenging. Herein, we develop a 12-electron transfer tetraalkynylporphyrin macrocycle positive electrode with two p-type amine (‒NH‒) motifs, two n-type imine (C = N) motifs and four n-type alkynyl (C ≡ C) motifs. The bipolar 18π-electron porphyrin macrocycle can alternately bind and release AlCl4− anions at ‒NH‒ sites and AlCl2+ cations at C = N sites (oxidized from 18π to 16π or reduced from 18π to 20π), achieving four electrons transfer. Furthermore, each terminal C ≡ C site can also coordinate with two AlCl2+ cations, thereby delivering eight electrons. The designed aluminum-organic battery achieves a high capacity of up to 347 mAh g−1 (3-6 times that of conventional graphite positive electrode, 60-120 mAh g−1) and a high specific energy of 312 Wh kg−1 (up to 150% compared to cells with graphite as positive electrode) based on the mass of positive electrode materials.

A Mixture Parameterized Biologically Based Dosimetry Model to Predict Body Burdens of PAHs in Developmental Zebrafish Toxicity Assays.

A Mixture Parameterized Biologically Based Dosimetry Model to Predict Body Burdens of PAHs in Developmental Zebrafish Toxicity Assays.

Rational synthesis of sea urchin-like NiCo-LDH/tannin carbon microsphere composites using microwave hydrothermal technique for high-performance asymmetric supercapacitor

In this study, tannin-derived porous carbon (TAC) with different microstructures was prepared via a microwave hydrothermal method, followed by KOH activation. Subsequently, the sea urchin–like NiCo-LDH/Tannin-derived carbon-based microsphere composite materials were rationally synthesized through a single-step microwave hydrothermal co-assembly process. The physicochemical characteristics and supercapacitive performance were systematically analyzed. TAC with a microspherical structure promoted and controlled the growth of LDHs, resulting in a more regular sea urchin–like structure, improved dispersibility, reduced resistance, and increased active sites. NiCo-LDH@TAC600-0 (without KOH activation) as an electrode material delivered a specific capacitance (Cs) of 1250 F g−1 at 1 A g−1 and 1035 F g−1 at 10 A g−1, with a rate performance of 82.8%. The asymmetric supercapacitor device using NiCo-LDH@TAC600-0 and TAC provided an energy density of 30.8 Wh kg−1 at 800 W kg−1 and a capacitance retention rate of 72.5% after 5000 cycles. This study offers a novel approach to enhancing NiCo-LDH properties for efficient energy storage.

Integrating network pharmacology, in silico molecular docking and experimental validation to explain the anticancer, apoptotic, and anti-metastatic effects of cosmosiin natural product against human lung carcinoma

Abstract Objectives This research aimed to examine the anticancer properties of cosmosiin, a natural flavonoid, on human lung carcinoma cells by in silico molecular docking, network pharmacology, and in vitro experiments. Methods The targets of cosmosiin and targets related to lung cancer were retrieved from various databases. The common targets between cosmosiin and lung cancer were identified by venny online server followed by construction of the protein-protein interaction (PPI) network. Further, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment were performed to identify main genes involved along with the signalling pathways affected. The hub genes were used for in silico molecular docking to identify molecular interaction between these targets and cosmosiin. In vitro experiments which consisted of MTT cell viability, clonogenic, cell apoptosis and cell migration assays validated the network pharmacology results. Results Network pharmacology identified 63 common targets between cosmosiin and lung cancer and out of these 63, eight protein targets were found to be most important based on their involvement in numerous signalling pathways in lung cancer. Two (NFKB1 and PIK3R1) out of eight targets showed highest degree values and were subjected to in silico molecular docking which showed cosmosiin showing strong binding the active sites of these two target proteins with PIK3R1 showing higher binding energy value (−9.7 kcal/ml) than NFKB1 (−7.5 kcal/mol). GO and KEGG enrichment analysis revealed key gene functions, molecular functions, cellular components as well as key signalling pathways involved in the treatment of lung cancer by cosmosiin. MTT and apoptotic assays indicated that cosmosiin induced concentration-dependent cytotoxic and apoptotic induction effects in A-549 human lung cancer cells respectively. Cell migration assay exhibited that cosmosiin treatment at varying doses led to a concentration-dependent suppression of cell migration hinting towards the anti-metastatic potency of cosmosiin against lung carcinoma. Conclusions In conclusion, the present study provides strong theoretical and experimental evidence of the anticancer, apoptotic and anti-metastatic potential of cosmosiin natural product against lung carcinoma along with the detailed mechanism of action involving various biological targets, cellular components and signalling pathways.

First-principles methods for unraveling the structure-catalytic activity relationship and mechanism of δ-MnO2-supported metal cluster catalysts in ambient temperature benzene to CO2 degradation.

Benzene, a volatile cyclic aromatic hydrocarbon, is frequently discharged into the environment and poses serious threats to human health. However, the effective degradation of benzene at low temperatures remains a formidable challenge in the field of environmental remediation. In this study, a series of 49 catalyst samples, spanning from single atoms to trimers and tetramers, supported on δ-MnO2 were meticulously constructed by employing the density functional theory (DFT) method. This approach facilitates an in-depth exploration of the structure-function relationship and enables the identification of prospective catalysts capable of degrading benzene into CO2 and H2O, thereby providing valuable insights for the development of efficient benzene degradation strategies at low temperatures. The obtained results unequivocally demonstrate that the separation between reaction products and reactants is substantially augmented with an increment in the number of active sites. Notably, the Ag4 tetramer exhibits a remarkable enhancement in this regard. Further in-depth analyses reveal that the superior catalytic activity of Ag4 relative to Pt4 and Pd4 tetramers can be ascribed to the closer energy alignment between the highest occupied molecular orbital (HOMO of Ag4) and the lowest unoccupied molecular orbital (LUMO of benzene), which facilitates electron transfer and reaction initiation. To assess the practical catalytic effectiveness, a detailed analysis of the reaction pathways for benzene degradation was carried out. Remarkably, the energy barrier of the rate-determining step was determined to be merely 0.71 eV at room temperature, comparable to those achieved under photocatalytic and high-temperature conditions. This finding is of great significance as it represents the first successful degradation of benzene by precisely controlling the size of metal clusters. Overall, this study not only provides valuable theoretical insights for benzene abatement but also paves the way for remediating related pollutants, heralding a new approach in the pursuit of sustainable environmental protection strategies.

High-entropy environments enable metal surface-catalyzed nucleophilic electrooxidation.

Electrochemical biomass conversion offers a sustainable route to diverse products, minimizing environmental impact. However, conventional 5-hydroxymethylfurfural electrooxidation (HMFOR) catalysts such as Ni(OH)2 and NiS suffer from low conductivity, poor stability, and limited active sites. This work introduces a CoNiMnMoPd high entropy alloy (HEA) to address these limitations by simultaneously maintaining high conductivity, stability, and a high Ni oxidation state, enabling nucleophilic dehydrogenation. The HEA catalyst achieved a 92.5% 2,5-furandicarboxylic acid (FDCA) Faradaic efficiency, 89.5% HMF conversion, and 95.8% FDCA selectivity, maintaining performance for over 100 hours. Experimental and theoretical investigations revealed that the multi-element composition of the HEA enabled Ni sites to maintain a high-valence state, serving as the primary adsorption sites for HMF, and the dehydrogenation reaction occurs preferentially at non-Ni sites within the HEA. Compared to monometallic Ni, the d-band center shift and reduced anti-bonding filling contributed to a decrease in the energy barrier for the rate-determining step (RDS) in the HMF-to-FDCA conversion, from 0.770 eV to 0.567 eV. This work offers novel insights for the development of Ni-based HEA catalysts for biomass valorization.

Super-dry reforming of methane using a tandem electro-thermocatalytic system.

Dry reforming of methane is a well-studied reaction for syngas production from CO2 and CH4. While the reaction is normally performed at a feed ratio of one, the envisioned future feedstocks contain far more CO2 and thus require extensive separation to use the desired CH4. Here we develop a three-step tandem electro-thermocatalytic CH4 reforming reaction for converting CO2-rich natural gas. The combination of the tandem CH4 reforming process with the reverse water-gas shift reaction and an oxygen-ion-conducting electrolysis-membrane reactor, in which water electrolysis shifts the equilibrium of the reverse water-gas shift reaction, promotes syngas production and increases the apparent CH4 reducibility. The catalyst, formed from the in situ exsolution of Rh nanoparticles on a CeO2-x support, provides substantial Ce3+-VO-Rhδ+ interfacial active sites for high catalytic performances. This tandem system used up to four CO2 molecules per CH4 molecule, afforded high CH4 and CO2 conversions and yielded high selectivity for CO and H2 production.

Flower-like amorphous metal-organic-frameworks-based hybrid-solid-state electrolyte for high-performance lithium-metal battery.

A flower-like porous amorphous Cu-aMOF-based SSE exhibits an ionic conductivity of 1.61 × 10-3 S cm-1 at 30 °C, a high lithium ion transference number of 0.71, and enables uniform Li deposition for 4000 h at 0.1 mA cm-2, demonstrating excellent cycling and rate performance. Compared to traditional crystalline Cu-MOF (1.18 × 10-3 S cm-1, 0.46, 1900 h), it shows significant improvements, highlighting the potential of amorphous MOFs with continuous structures, abundant defects, and more active sites as novel electrolyte materials for high-performance lithium-metal batteries.

Hydrogen Binding Energy Is Insufficient for Describing Hydrogen Evolution on Single-Atom Catalysts.

The design principles for metal-nitrogen-carbon (M-N-C) single-atom catalysts (SACs) in the hydrogen evolution reaction (HER) have been extensively studied. While hydrogen binding energy ([[EQUATION]]) has long been used as a HER descriptor during the past decades,its applicability to HER SACs has been met with significant controversy. Herein, we investigate the effects of HO*/O* poisoning and H* coverage on SACs with varied metal centers and coordination environments using pH-dependent surface Pourbaix diagrams at the reversible hydrogen electrode (RHE) scale and microkinetic modeling. Our findings reveal that HO* poisoning, realistic H* adsorption strengths at active metal sites, and the potential HER activity at the coordinating N-sites are crucial factors that should be considered for accurate descriptor development. Experimental validation using a series of M-phthalocyanine/CNT catalystsconfirms the theoretical predictions, with excellent agreement in exchange current densities and the role of N-sites in Ni/Cu-phthalocyanine/CNT catalysts. More importantly, the controversy surrounding HER SAC design principles is resolved through a novel 2D microkinetic volcano model that incorporates active sites, H* coverage, and HO* poisoning. This work provides answers to a long-lasting debate on HER descriptors by establishing [[EQUATION]] and [[EQUATION]] as a combined HER descriptor for SACs, offering new guidelines for catalyst design.

Regulating Electron Distribution in Regioisomeric Covalent Organic Frameworks for Efficient Solar-Driven Hydrogen Peroxide Production.

Covalent organic frameworks (COFs) are emerging as a transformative platform for photocatalytic hydrogen peroxide (H2O2) production due to their highly ordered structures, intrinsic porosity, and molecular tunability. Despite their potential, the inefficient utilization of photogenerated charge carriers in COFs significantly restrains their photocatalytic efficiency. This study presents two regioisomeric COFs, α-TT-TDAN COF and β-TT-TDAN COF, both incorporating thieno[3,2-b]thiophene moieties, to investigate the influence of regioisomerism on the excited electron distribution and its impact on photocatalytic performance. The β-TT-TDAN COF demonstrates a remarkable solar-to-chemical conversion efficiency of 1.35%, outperforming its α-isomeric counterpart, which is merely 0.44%. Comprehensive spectroscopic and computational investigations reveal the critical role of subtle substitution change in COFs on their electronic properties. This structural adjustment intricately connects molecular structure to charge dynamics, enabling precise regulation of electron distribution, efficient charge separation and transport, and localization of excited electrons at active sites. Moreover, this finely tuned interplay significantly enhances the efficiency of the oxygen reduction reaction. These findings establish a new paradigm in COF design, offering a molecular-level strategy to advance COFs and reticular materials toward highly efficient solar-to-chemical energy conversion.

Photonic Sintering as an Electrode Structuring Process to Improve Electrocatalytic Activity and Durability in Anion Exchange Membrane Water Electrolysis.

Hydrogen production via water electrolysis is essential for achieving carbon-free energy. However, enhancing the performance of these systems, particularly at the electrode level, remains challenging. Photonic sintering (PS) is proposed as a highly effective post-treatment method for electrodes, highlighting the importance of electrode design and optimization. PS significantly enhances the catalytic activity and durability of spinel-type copper-cobalt oxide-based anodes for the oxygen evolution reaction and Pt@C-based cathodes for the hydrogen evolution reaction, which are attributed to structural and chemical modifications, including active site control, optimized surface chemical bonding, improved catalyst-substrate adhesion, and generation of a reduced surface. PS-treated electrodes maintain well-preserved electrochemical active sites and pore structures, which are crucial for activation polarization and mass transport kinetics. Consequently, an anion exchange membrane water electrolysis cell with PS-treated electrodes achieved 89.57% cell efficiency, 3.91 W cm-2 area-specific power at 1.8 V, and a low degradation rate of 0.049 mV h-1 (at 0.5 A cm-2) and 0.136 mV h-1 (at 1.0 A cm-2) over 500 h. This research overcomes the traditional trade-off between activity and durability, indicating that PS can be widely applied across various energy fields, including electrochemical storage and conversion.

Computational profiling of molecular biomarkers in congenital disorders of glycosylation Type-I and binding analysis of Ginkgolide A with P4HB.

Computational profiling of molecular biomarkers in congenital disorders of glycosylation Type-I and binding analysis of Ginkgolide A with P4HB.

MOF-Derived Ni5P4 Nanoparticles Based on the Microemulsion Strategy for Supercapacitors and Water Splitting.

With the rapid advancement of energy storage and conversion systems (ESCSs), renewable energy can achieve a smooth and continuous output capacity. Nevertheless, commercial precious metal-based multifunctional ESCSs materials are plagued by issues like scarcity and high production costs. This study adopted microemulsion and chemical vapor deposition (CVD) strategies to fabricate single crystal Ni5P4 nanoparticles successfully. Due to its excellent crystal integrity and high electrical conductivity, single crystal Ni5P4 offers abundant active sites for redox reactions. Additionally, it allows electrons and ions to move more efficiently and freely, making it a highly promising multifunctional material for ESCSs. For supercapacitors (SCs), the prepared Ni5P4-10 electrode possesses a battery-like behavior with a high specific capacity of 1643.13 F g-1@0.5 A g-1. The corresponding assembled Ni5P4-10//AC hybrid SCs (HSCs) exhibit a maximum energy density of 37.78 Wh kg-1 at a power density of 400 W kg-1. Furthermore, Ni5P4-10 displays low overpotentials of 150 mV@HER and 250 mV@OER at 10 mA cm-2 when it serves as an electrocatalyst. This study offers a novel perspective for the design of MOF-derived multifunctional ESCSs materials.

Constructing of Ni-Nx Active Sites in Self-Supported Ni Single-Atom Catalysts for Efficient Reduction of CO2 to CO

Constructing of Ni-Nx Active Sites in Self-Supported Ni Single-Atom Catalysts for Efficient Reduction of CO2 to CO

Unraveling CO-Tolerance Mechanism in Proton Exchange Membrane Fuel Cells via Operando Infrared Spectroscopy.

CO poisoning remains a critical challenge for proton exchange membrane fuel cells (PEMFCs). Current studies of CO tolerance primarily focus on solid/liquid interfaces (in-situ conditions), which differ significantly from PEMFCs' solid/liquid/gas triple-phase interfaces (operando conditions) in microenvironment and mass transport. Herein, we developed an operando transmission infrared spectroscopy method that enables direct observation of CO tolerance mechanism on commercial PtRu/C catalysts in PEMFCs. Under in-situ conditions, hydrogen oxidation reaction (HOR) activity is governed by CO mass transfer, and is insensitive to the availability of active sites, while it is highly sensitive under operando conditions due to enhanced mass transfer, thereby aggravating CO poisoning effects. Notably, 76% of HOR activity can recover upon switching to pure H2. Based on CO band evolution, we proposed a new pathway beyond the traditional bifunctional mechanism of CO tolerance: CO migrates from Pt to Ru sites, undergoing oxidation at potentials as low as 0.01 V vs.reversible hydrogen electrode (RHE).

Phase Transition Engineering of Metal-Organic Frameworks Induces Multiphase Complexation for Enhancing the Oxygen Evolution Reaction.

Phase transition engineering of metal-organic frameworks (MOFs) presents a promising strategy for enhancing electrocatalytic performance in water splitting applications. In this study, we demonstrate a controlled phase transition strategy to synthesize a multiphase composite (op&cp) composed of open phase (op) and closed phase (cp) through precise desolvation treatment. When used as an alkaline water electrocatalyst, op&cp exhibits exceptional oxygen evolution reaction (OER) performance, achieving a remarkably low overpotential of 140 mV under 10 mA cm-2 and maintaining stable operation for over 75 h at 100 mA cm-2. In situ Raman spectroscopy and X-ray photoelectron spectroscopy show that the catalytically active substance NiOOH is formed on the engineered phase with a lower potential (1.2 V vs RHE) than the single-phase material (1.3 V vs RHE). This work establishes phase transition engineering as a viable strategy for improving MOF-based catalysis and explores the fundamental mechanism of the dynamic evolution of active sites during the OER.

Double-Chain Copolymer Network via In Situ Polymerization Enables High-Stability and Lead-Safe Perovskite Solar Cells.

Lead halide perovskite solar cells (PSCs) have made significant progress due to their low cost and high efficiency. However, the long-term stability and lead toxicity of PSCs remain a huge challenge for further commercialization. Herein, we designed a multifunctional additive PAE with photosensitive properties to overcome these difficulties. A unique double-chain copolymer network can be constructed via in situ polymerization induced by ultraviolet (UV) light. The multiple active sites in the polymer chains can passivate various defects and enhance charge transfer. Meanwhile, the vast network provides an effective defense for perovskite to stabilize the internal structure and resist harsh external environments, thus delaying the degradation of devices and maximizing the suppression of toxic lead leakage. Remarkably, the devices protected by the network achieved a champion power conversion efficiency (PCE) of 26.20% (certified as 25.69%), the unencapsulated devices suppressed 80% of lead leakage and the encapsulated devices maintained 93% of the initial PCE after 1000 h in a humid and thermal environment (65 °C and 85% RH).