Photochemical engineering unsaturated Pt islands on supported Pd nanocrystals for a robust pH-universal hydrogen evolution reaction.

The rational design of heterostructured nanocrystals (HNCs) is of great significance for developing highly efficient hydrogen evolution reaction (HER) electrocatalysts. However, a significant challenge still lies in realizing the controllable synthesis of desired HNCs directly onto a support and exploring their structure-activity-dependent HER performance. Herein, we reported various controllable Pd7@Ptx core-shell HNCs with optimal hybrid structures via a photochemical deposition strategy. The growth patterns of a Pt shell can be finely controlled by adjusting the growth kinetics, resulting in a varying deposition rate. In particular, the as-prepared Pd7@Pt3 HNCs with a Pt shell in the Stranski-Krastanov mode showed the best performances over a wide pH range media, delivering low overpotentials of 33, 18 and 49 mV, resulting in a catalytic current density of 10 mA cm-2 at a low effective catalyst loading of 0.021 mg cm-2. The resulting Tafel slopes were 23.1, 52.6 and 42.7 mV dec-1 in 0.5 M H2SO4, 1.0 M phosphate-buffered saline (PBS) and 1.0 M KOH electrolyte, respectively. It was found that the increased fraction of unsaturated coordination of Pt islands in the resultant material is the key to the enhanced and robust HER activity, which has been confirmed through density functional theory (DFT) calculations. This strategy could be extended to the rational design and synthesis of other heterostructured catalysts for energy conversion and storage.

Comparative Study of Machine Learning-Based QSAR Modeling of Anti-inflammatory Compounds from Durian Extraction.

Quantitative structure-activity relationship (QSAR) analysis, an in silico methodology, offers enhanced efficiency and cost effectiveness in investigating anti-inflammatory activity. In this study, a comprehensive comparative analysis employing four machine learning algorithms (random forest (RF), gradient boosting regression (GBR), support vector regression (SVR), and artificial neural networks (ANNs)) was conducted to elucidate the activities of naturally derived compounds from durian extraction. The analysis was grounded in the exploration of structural attributes encompassing steric and electrostatic properties. Notably, the nonlinear SVR model, utilizing five key features, exhibited superior performance compared to the other models. It demonstrated exceptional predictive accuracy for both the training and external test datasets, yielding R2 values of 0.907 and 0.812, respectively; in addition, their RMSE resulted in 0.123 and 0.097, respectively. The study outcomes underscore the significance of specific structural factors (denoted as shadow ratio, dipole z, methyl, ellipsoidal volume, and methoxy) in determining anti-inflammatory efficacy. Thus, the findings highlight the potential of molecular simulations and machine learning as alternative avenues for the rational design of novel anti-inflammatory agents.

A 3D Cross-Linked Metal-Organic Framework (MOF)-Derived Polymer Electrolyte for Dendrite-Free Solid-State Lithium-Ion Batteries.

Lithium metal batteries (LMBs) with high energy density have received widespread attention; however, there are usually issues with lithium dendrite growth and safety. Therefore, there is a demand for solid electrolytes with high mechanical strength, room-temperature ionic conductivity, and good interface performance. Herein, a 3D cross-linked metal-organic framework (MOF)-derived polymer solid electrolyte exhibits good mechanical and ionic conductive properties simultaneously, in which the MOF with optimized pore size and strong imidazole cation sites can restrict the migration of anions, resulting in a uniform Li+ flux and a high lithium-ion transference number (0.54). Moreover, the MOF-derived polymer solid electrolytes with the 3D cross-linked network can promote the rapid movement of Li+ and inhibit the growth of lithium dendrites. Lithium symmetric batteries assembled with the 3D MOF-derived polymer solid electrolytes are subjected to lithium plating/stripping and cycled over 2000 h at a current density of 0.1 mA cm-2 and over 800 h at a current density of 0.2 mA cm-2 . The Li/P-PETEA-MOF/LiFePO4 batteries exhibit excellent long-cycle stability and cycle reversibility.

Design of electron-donating group substituted 2-PAM analogs as antidotes for organophosphate insecticide poisoning.

The use of organophosphate (OPs) pesticides is widespread in agriculture and horticulture, but these chemicals can be lethal to humans, causing fatalities and deaths each year. The inhibition of acetylcholinesterase (AChE) by OPs leads to the overstimulation of cholinergic receptors, ultimately resulting in respiratory arrest, seizures, and death. Although 2-pralidoxime (2-PAM) is the FDA-approved drug for treating OP poisoning, there is difficulty in blood-brain barrier permeation. To address this issue, we designed and evaluated a series of 2-PAM analogs by substituting electron-donating groups on the para and/or ortho positions of the pyridinium core using in silico techniques. Our PCM-ONIOM2 (MP2/6-31G*:PM7//B3LYP/6-31G*:UFF) binding energy results demonstrated that 13 compounds exhibited higher binding energy than 2-PAM. The analog with phenyl and methyl groups substituted on the para and ortho positions, respectively, showed the most favorable binding characteristics, with aromatic residues in the active site (Y124, W286, F297, W338, and Y341) and the catalytic residue S203 covalently bonding with paraoxon. The results of DS-MD simulation revealed a highly favorable apical conformation of the potent analog, which has the potential to enhance reactivation of AChE. Importantly, newly designed compound demonstrated appropriate drug-likeness properties and blood-brain barrier penetration. These results provide a rational guide for developing new antidotes to treat organophosphate insecticide toxicity.

A Surfactant-Free and General Strategy for the Synthesis of Bimetallic Core-Shell Nanocrystals on Reduced Graphene Oxide through Targeted Photodeposition.

Tunable physicochemical properties of bimetallic core-shell heterostructured nanocrystals (HNCs) have shown enormous potential in electrocatalytic reactions. In many cases, HNCs are required to load on supports to inhibit catalyst aggregation. However, the introduction of supports during the process of growing core-shell HNCs makes the synthesis much more complicated and difficult to control precisely. Herein, we reported a universal photochemical synthetic strategy for the controlled synthesis of well-defined surfactant-free core-shell metal HNCs on a reduced graphene oxide (rGO) support, which was assisted by the fine control of photogenerated electrons directly transferring to the targeted metal seeds via rGO and the precisely tuned adsorption capacity of the added second metal precursors. The surface photovoltage microscopy (SPVM) platform proved that photogenerated electrons flowed through rGO to Pd particles under illumination. We have successfully synthesized 24 different core-shell metal HNCs, i.,e., MA@MB (MA = Pd, Au, and Pt; MB = Au, Ag, Pt, Pd, Ir, Ru, Rh, Ni and Cu), on the rGO supports. The as-prepared Pd@Cu core-shell HNCs showed outstanding performance in the electrocatalytic reduction of CO2 to CH4. This work could shed light on the controlled synthesis of more functional bimetallic nanostructured materials on diverse supports for various applications.

3D-printed biodegradable magnesium alloy scaffolds with zoledronic acid-loaded ceramic composite coating promote osteoporotic bone defect repair.

Osteoporotic fracture is one of the most serious complications of osteoporosis. Most fracture sites have bone defects, and restoring the balance between local osteogenesis and bone destruction is difficult during the repair of osteoporotic bone defects. In this study, we successfully fabricated three-dimensional (3D)-printed biodegradable magnesium alloy (Mg-Nd-Zn-Zr) scaffolds and prepared a zoledronic acid-loaded ceramic composite coating on the surface of the scaffolds. The osteogenic effect of Mg and the osteoclast inhibition effect of zoledronic acid were combined to promote osteoporotic bone defect repair. In vitro degradation and drug release experiments showed that the coating significantly reduced the degradation rate of 3D-printed Mg alloy scaffolds and achieved a slow release of loaded drugs. The degradation products of drug-loaded coating scaffolds can promote osteogenic differentiation of bone marrow mesenchymal stem cells as well as inhibit the formation of osteoclasts and the bone resorption by regulating the expression of related genes. Compared with the uncoated scaffolds, the drug-coated scaffolds degraded at a slower rate, and more new bone grew into these scaffolds. The healing rate and quality of the osteoporotic bone defects significantly improved in the drug-coated scaffold group. This study provides a new method for theoretical research and clinical treatment using functional materials for repairing osteoporotic bone defects.

Highly Selective Catalytic Oxi-upcycling of Polyethylene to Aliphatic Dicarboxylic Acid under a Mild Hydrogen-Free Process.

A low-temperature hydrogen-free process for upcycling polyethylene (PE) plastics into aliphatic dicarboxylic acid is developed using a heterogeneous catalyst Ru/TiO2 . The low-density PE (LDPE) conversion can reach 95 % in 24 h under a pressure of 1.5 MPa air at 160 °C with 85 % of the liquid product yield, which mainly is low molecular weight aliphatic dicarboxylic acid. Excellent performances can be also achieved for different PE feedstocks. This catalytic oxi-upcycling process paving a new way of upcycling polyethylene waste.

Quantitative Structure-Electrochemistry Relationship (QSER) Studies on Metal-Amino-Porphyrins for the Rational Design of CO2 Reduction Catalysts.

The quantitative structure-electrochemistry relationship (QSER) method was applied to a series of transition-metal-coordinated porphyrins to relate their structural properties to their electrochemical CO2 reduction activity. Since the reactions mainly occur within the core of the metalloporphyrin catalysts, the cluster model was used to calculate their structural and electronic properties using density functional theory with the M06L exchange-correlation functional. Three dependent variables were employed in this work: the Gibbs free energies of H*, C*OOH, and O*CHO. QSER, with the genetic algorithm combined with multiple linear regression (GA-MLR), was used to manipulate the mathematical models of all three Gibbs free energies. The obtained statistical values resulted in a good predictive ability (R2 value) greater than 0.945. Based on our QSER models, both the electronic properties (charges of the metal and porphyrin) and the structural properties (bond lengths between the metal center and the nitrogen atoms of the porphyrin) play a significant role in the three Gibbs free energies. This finding was further applied to estimate the CO2 reduction activities of the metal-monoamino-porphyrins, which will prove beneficial in further experimental developments.

Rational Design of a Low-Data Regime of Pyrrole Antioxidants for Radical Scavenging Activities Using Quantum Chemical Descriptors and QSAR with the GA-MLR and ANN Concepts.

A series of pyrrole derivatives and their antioxidant scavenging activities toward the superoxide anion (O2•-), hydroxyl radical (•OH), and 1,1-diphenyl-2-picryl-hydrazyl (DPPH•) served as the training data sets of a quantitative structure-activity relationship (QSAR) study. The steric and electronic descriptors obtained from quantum chemical calculations were related to the three O2•-, •OH, and DPPH• scavenging activities using the genetic algorithm combined with multiple linear regression (GA-MLR) and artificial neural networks (ANNs). The GA-MLR models resulted in good statistical values; the coefficient of determination (R2) of the training set was greater than 0.8, and the root mean square error (RMSE) of the test set was in the range of 0.3 to 0.6. The main molecular descriptors that play an important role in the three types of antioxidant activities are the bond length, HOMO energy, polarizability, and AlogP. In the QSAR-ANN models, a good R2 value above 0.9 was obtained, and the RMSE of the test set falls in a similar range to that of the GA-MLR models. Therefore, both the QSAR GA-MLR and QSAR-ANN models were used to predict the newly designed pyrrole derivatives, which were developed based on their starting reagents in the synthetic process.

An Asymmetric Cross-Linked Ionic Copolymer Hybrid Solid Electrolyte with Super Stretchability for Lithium-Ion Batteries.

Composite solid electrolytes are recommended to be the most promissing strategy for solid-state batteries because they combine the advantages of inorganic ceramics and polymers. However, the huge interfacial resistance between the inorganic ceramic and polymer results in low ionic conductivity, which is still the major impediment that limits their applications. Herein, a novel highly elastic and weakly coordinated ionic copolymer hybrid electrolyte with asymmetric structure based on surface-modified Li1.5 Al0.5 Ge1.5 (PO4 )3 by "in situ" polymerization is proposed to improve ionic conductivity and mechanical properties simultaneously. The all-solid hybrids electrolytes exhibit room-temperature ionic conductivity up to 2.61 × 10-4 S cm-1 and lithium-ion transference number of 0.41. The hybrids electrolytes can be repeatedly stretching-releasing-stretching, showing a super stretchability with the elongation at break up to 496%. The Li symmetrical cells assembled with the hybrid electrolytes can continuously operate for 800 h at 0.1 mA cm-2 without discernable dendrites, indicating good interfacial compatibility between the hybrid electrolytes and lithium electrodes. The Li|LiFePO4 batteries assembled with the hybrid electrolytes deliver an initial discharge specific capacity of 165.5 mAh g-1 with an initial coulombic efficiency of 94.8% and 154 mAh g-1 after 100 cycles at 0.1 C, and maintain 95.4% capacity retention after 100 cycles at 0.5 C.

High-Rate Organic Cathode Constructed by Iron-Hexaazatrinaphthalene Tricarboxylic Acid Coordination Polymer for Li-Ion Batteries.

The sluggish ion-transport in electrodes and low utilization of active materials are critical limitations of organic cathodes, which lead to the slow reaction dynamics and low specific capacity. In this study, the hierarchical tube is constructed by iron-hexaazatrinaphthalene tricarboxylic acid coordination polymer (Fe-HATNTA), using HATNTA as the self-engaged template to coordinate with Fe2+ ions. This Fe-HATNTA tube with hierarchical porous structure ensures the sufficient contact between electrolyte and active materials, shortens the diffusion distance, and provides more favorable transport pathways for ions. When employed as the cathode for rechargeable Li-ion batteries, Fe-HATNTA delivers a high specific capacity (244 mAh g-1 at 50 mA g-1 , 91% of theoretical capacity), excellent rate capability (128 mAh g-1 at 9 A g-1 ), and a long-term cycle life (73.9% retention over 3000 cycles at 5 A g-1 ). Moreover, the Li+ ions storage and conduction mechanisms are further disclosed by the ex situ and in situ characterizations, kinetic analyses, and theoretical calculations. This work is expected to boost further enthusiasm for developing the hierarchical structured metal-organic coordination polymers with superb ionic storage and transport as high-performance organic cathodes.

Protocol on irradiation-dark photochemical deposition and characterization of metal nanoclusters on semiconductor support.

Controlling the size and uniform dispersion of noble metal nanoclusters on the metal oxide based semiconductor are difficult due to the natural tendency for metal atoms to agglomerate. Here, we present the protocol for an "irradiation-dark" photochemical deposition to obtain uniform metal nanoclusters on semiconductor support, and the protocol for measuring the size and size distribution of metal nanoclusters. For complete details on the use and execution of this protocol, please refer to Wu et al. (2022).

Enhanced rate capability and high-voltage cycling stability of single-crystal nickel-rich cathode by surface anchoring dielectric BaTiO3.

The single-crystal Ni-rich Li(NixCoyMn1-x-y)O2 cathode (NCM) demonstrates better cycle performance, enhanced tap density and improved mechanical structure stability, compared with polycrystalline NCM.However, limited Li+ transports, (003) plane slips and microcracks in large single particles hinder rate capability and cycle performance. To overcome these shortcomings,single-crystal NCM cathodes have been modified by nanosized tetragonal BaTiO3. Due to the dielectric properties, BaTiO3 particles induce electric field concentration at the BaTiO3-NCM-electrolyte interface. Thus, a large amount of lithium vacancies can be formed, providing sufficient sites for the hopping diffusion of lithium ions, thereby significantly enhancing the diffusion coefficient of Li+. Moreover, the redistribution of charges can inhibit the formation and accumulation of cathode-electrolyte-interface. Owing to the synergetic effect of BaTiO3, the BT-modified single-crystal NCM with the optimized loading shows a remarkable initial discharge capacity of 138.5 mAh g-1 and maintains 53.8% of its initial discharge capacity after 100 cycles under 5C at 4.5 V cut-off voltage. Overall, the proposed dielectric cathode-electrolyte-interface strategy can enhance Li+ ion transport and stabilize the interface structure, leading to improved rate performance. Meanwhile, the diffusion-induced state of charge gradient can also be inhibited, resulting in high structure stability of single-crystal NCMs under high rate and cut-off voltage cycling.

SO2-Tolerant Catalytic Reduction of NOx via Tailoring Electron Transfer between Surface Iron Sulfate and Subsurface Ceria.

Currently, SO2-induced catalyst deactivation from the sulfation of active sites turns to be an intractable issue for selective catalytic reduction (SCR) of NOx with NH3 at low temperatures. Herein, SO2-tolerant NOx reduction has been originally demonstrated via tailoring the electron transfer between surface iron sulfate and subsurface ceria. Engineered from the atomic layer deposition followed by the pre-sulfation method, the structure of surface iron sulfate and subsurface ceria was successfully constructed on CeO2/TiO2 catalysts, which delivered improved SO2 resistance for NOx reduction at 250 °C. It was demonstrated that the surface iron sulfate inhibited the sulfation of subsurface Ce species, while the electron transfer from the surface Fe species to the subsurface Ce species was well retained. Such an innovative structure of surface iron sulfate and subsurface ceria notably improved the reactivity of NHx species, thus endowing the catalysts with a high NOx reaction efficiency in the presence of SO2. This work unraveled the specific structure effect of surface iron sulfate and subsurface ceria on SO2-toleant NOx reduction and supplied a new point to design SO2-tolerant catalysts by modulating the unique electron transfer between surface sulfate species and subsurface oxides.

Shape-Controlled Photochemical Synthesis of Noble Metal Nanocrystals Based on Reduced Graphene Oxide.

The fabrication of supported noble metal nanocrystals (NCs) with well-controlled morphologies have been attracted considerable interests due to their merits in a wide variety of applications. Photodeposition is a facile and effective method to load metals over semiconductors in a simple slurry reactor under irradiation. By optimizing the photodeposition process, the size, chemical states, and the geometrical distribution of metal NCs have been successfully tuned. However, metal NCs with well-controlled shapes through the photodeposition process have not been reported until now. Here, we report our important advances in the controlled photodeposition process to load regular noble metal NCs. Reduced graphene oxide (rGO) is introduced as a reservoir for the fast transfer of photoelectrons to avoid the fast accumulation of photogenerated electrons on the noble metals which makes the growth process uncontrollable. Meanwhile, rGO also provides stable surface for the controlled nucleation and oriented growth. Noble metal NCs with regular morphologies are then evenly deposited on rGO. This strategy has been demonstrated feasible for different precious metals (Pd, Au, and Pt) and semiconductors (TiO2, ZnO, ZrO2, CeO2, and g-C3N4). In the prototype application of electrochemical hydrogen evolution reaction, regular Pd NCs with enclosed {111} facets showed much better performance compared with that of irregular Pd NCs.

Self-Defense Effects of Ti-Modified Attapulgite for Alkali-Resistant NOx Catalytic Reduction.

Nowadays, the serious deactivation of deNOx catalysts caused by alkali metal poisoning was still a huge bottleneck in the practical application of selective catalytic reduction of NOx with NH3. Herein, alkali-resistant NOx catalytic reduction over metal oxide catalysts using Ti-modified attapulgite (ATP) as supports has been originally demonstrated. The self-defense effects of Ti-modified ATP for alkali-resistant NOx catalytic reduction have been clarified. Ti-modified ATP with self-defense ability was obtained by removing alkaline metal cation impurities in the natural ATP materials without destroying its initial layered-chain structure through the ion-exchange procedure, accompanied with an obvious enrichment of Brønsted acid and Lewis acid sites. The self-defense effects embodied that both ion-exchanged Ti octahedral centers and abundant Si-OH sites in the Ti-ion-exchange-modified ATP could effectively anchor alkali metals via coordinate bonding or ion-exchange process, which induced alkali metals to be immobilized by the Ti-ion-exchange-modified ATP carrier rather than impair active species. Under this special protection of self-defense effects, Ti-ion-exchange-modified ATP supported catalysts still retained plentiful acidic sites and superior redox ability even after alkali metal poisoning, giving rise to the maintenance of sufficient NHx and NOx adsorption and the subsequent efficient reaction, which in turn resulted in high NOx catalytic reduction capacity of the catalyst. The strategy provided new inspiration for the development of novel and efficient selective catalytic reduction of NOx with NH3 (NH3-SCR) catalysts with high alkali resistance.

High-Performance Microsized Si Anodes for Lithium-Ion Batteries: Insights into the Polymer Configuration Conversion Mechanism.

Microsized silicon particles are desirable Si anodes because of their low price and abundant sources. However, it is challenging to achieve stable electrochemical performances using a traditional microsized silicon anode due to the poor electrical conductivity, serious volume expansion, and unstable solid electrolyte interface. Herein, a composite microsized Si anode is designed and synthesized by constructing a unique polymer, poly(hexaazatrinaphthalene) (PHATN), at a Si/C surface (PCSi). The Li+ transport mechanism of the PCSi is elucidated by using in situ characterization and theoretical simulation. During the lithiation of the PCSi anode, CN groups with high electron density in the PHATN first coordinate Li+ to form CNLi bonds on both sides of the PHATN molecule plane. Consequently, the original benzene rings in the PHATN become active centers to accept lithium and form stable Li-rich PHATN coatings. PHATN molecules expand due to the change of molecular configuration during the consecutive lithiation process, which provides controllable space for the volume expansion of the Si particles. The PCSi composite anode exhibits a specific capacity of 1129.6 mAh g-1 after 500 cycles at 1 A g-1 , and exhibits compelling rate performance, maintaining 417.9 mAh g-1 at 16.5 A g-1 .

Photo-assisted sequential assembling of uniform metal nanoclusters on semiconductor support.

Dispersing metal nanoclusters on the oxide supports is attracting close attention in heterogeneous catalysis, but great challenges still lie in controlling the size and dispersion of nanoclusters due to the inevitable agglomeration. Here, we propose a sequential photochemical deposition strategy named "first store, and then release" to uniformly fabricate the size-controlling noble metal nanoclusters on semiconductor oxides. Using the typical semiconductor TiO2, the photoexcited electrons can be first stored as reduced species (e.g. Ti3+) under irradiation and the Ti3+ species can optimize both the nucleation and growth processes in dark reaction, resulting in a uniform dispersing of various noble metals (Au, Pt, Ag etc.) with size diameters of ∼1 nm. The nanoclusters catalysts exhibited superior performance in catalytic oxidation of HCHO compared with that of nanoparticles. This work brings a new and useful strategy to construct size-controlling noble metals on the oxide supports for heterogeneous catalysis and the related fields.

Localized surface plasmon resonance induced assembly of bimetal nanochains.

Bimetal nanochains (NCs) are attracting increasing attention in the fields of catalysis and electrocatalysis due to the synergistic effects in electronic and optical properties, but the fabrication of bimetal NCs remains challenging. Here, we report a general strategy named "nucleation in the irradiation then growth in the dark" for the preparation of Au/M (second metal) NCs. In the irradiation stage, the localized surface plasmon resonance (LSPR) effect of Au NPs is excited to overcome the nucleation energy barrier for the deposition of second metals (Pt, Ag and Pd). In the followed dark process, the preferential growth of second metals on the existed nucleus leads to the formation of nanochain rather than the core/shell nanostructure. In the model reaction of electrocatalytic hydrogen evolution, the optimized Au/Pt NCs showed much better performance compared with the commercial Pt/C.

SBA-15 with Crystalline Walls Produced via Thermal Treatment with the Alkali and Alkali Earth Metal Ions.

Crystalline walled SBA-15 with large pore size were prepared using alkali and alkali earth metal ions (Na+, Li+, K+ and Ca2+). For this work, the ratios of alkali metal ions (Si/metal ion) ranged from 2.1 to 80, while the temperatures tested ranged from 500 to 700 °C. The SBA-15 prepared with Si/Na+ ratios ranging from 2.1 to 40 at 700 °C exhibited both cristobalite and quartz SiO2 structures in pore walls. When the Na+ amount increased (i.e., Si/Na increased from 80 to 40), the pore size was increased remarkably but the surface area and pore volume of the metal ion-based SBA-15 were decreased. When the SBA-15 prepared with Li+, K+ and Ca2+ ions (Si/metal ion = 40) was thermally treated at 700 °C, the crystalline SiO2 of quartz structure with large pore diameter (i.e., 802.5 Å) was observed for Ca+2 ion-based SBA-15, while no crystalline SiO2 structures were observed in pore walls for both the K+ and Li+ ions treated SBA-15. The crystalline SiO2 structures may be formed by the rearrangement of silica matrix when alkali or alkali earth metal ions are inserted into silica matrix at elevated temperature.