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Oxygen-containing carbons are promising supports and metal-free catalysts for many reactions. However, distinguishing the role of various oxygen functional groups and quantifying and tuning each functionality is still difficult. Here we investigate the role of Brønsted acidic oxygen-containing functional groups by synthesizing a diverse library of materials. By combining acid-catalyzed elimination probe chemistry, comprehensive surface characterizations, 15 N isotopically labeled acetonitrile adsorption coupled with magic-angle spinning nuclear magnetic resonance, machine learning, and density-functional theory calculations, we demonstrate that phenolic is the main acid site in gas-phase chemistries and unexpectedly carboxylic groups are much less acidic than phenolic groups in the graphitized mesoporous carbon due to electron density delocalization induced by the aromatic rings of graphitic carbon. The methodology can identify acidic sites in oxygenated carbon materials in solid acid catalyst-driven chemistry. Distinguishing the influence of oxygen functional groups in carbon materials is important but elusive. Here, the authors combine experimental and machine learning techniques and reveal that phenolic groups are more acidic than carboxylic groups.

The active site environment in enzymes has been known to affect catalyst performance through weak interactions with a substrate, but precise synthetic control of enzyme inspired heterogeneous catalysts remains challenging. Here, we synthesize hyper-crosslinked porous polymer (HCPs) with solely -OH or -CH 3 groups on the polymer scaffold to tune the environment of active sites. Reaction rate measurements, spectroscopic techniques, along with DFT calculations show that HCP-OH catalysts enhance the hydrogenation rate of H-acceptor substrates containing carbonyl groups whereas hydrophobic HCP- CH 3 ones promote non-H bond substrate activation. The functional groups go beyond enhancing substrate adsorption to partially activate the C = O bond and tune the catalytic sites. They also expose selectivity control in the hydrogenation of multifunctional substrates through preferential substrate functional group adsorption. The proposed synthetic strategy opens a new class of porous polymers for selective catalysis. Weak interactions between substrates and the active site environment have been known to be vital in enzyme catalysis. Inspired by this, the authors synthesize hyper-crosslinked porous polymer-based catalysts with different H-bonds to enhance adsorption and modify the interfacial sites and reactivity.

Selective C–O activation of multifunctional molecules is essential for many important chemical processes. Although reducible metal oxides are active and selective towards reductive C–O bond scission via the reverse Mars–van Krevelen mechanism, the most active oxides undergo bulk reduction during reaction. Here, motivated by the enhanced oxide reducibility by metals, we report a strategy for C–O bond activation by doping the surface of moderately reducible oxides with an ultralow loading of noble metals. We demonstrate the principle using highly dispersed Pt anchored onto TiO 2 for furfuryl alcohol conversion to 2-methylfuran. A combination of density functional theory calculations, catalyst characterization (scanning transmission electron microscopy, electron paramagnetic resonance, Fourier-transform infrared spectroscopy and X-ray absorption spectroscopy), kinetic experiments and microkinetic modelling expose substantial C–O activation rate enhancement, without bulk catalyst reduction or unselective ring hydrogenation. A methodology is introduced to quantify various types of sites, revealing that the cationic redox Pt on the TiO 2 surface is more active than metallic sites for C–O bond activation. Reducible metal oxides selectively catalyse the hydrodeoxygenation of C–O bonds in bio-based aromatic molecules, although they show limited performance. Now, using TiO 2 as an example, a method is reported to enhance the activity of the oxide by surface doping with an ultralow loading of Pt.

Brønsted acid sites on the oxide overlayers of metal–metal oxide inverse catalysts are often hypothesized to drive selective C–O bond activation. However, the Brønsted acid site nature and dynamics under working conditions remain poorly understood due to the functionalities of the constituent materials. Here we investigate the formation and the dynamics of Brønsted acid and redox sites on PtWO x /C under working conditions. Density functional theory-based thermodynamic calculations and microkinetic modelling reveal a complex interplay between Brønsted acid and redox sites and potentially fast catalyst dynamics at comparable timescales to the Brønsted acid catalysed dehydration chemistry. Combining in situ characterization and probe chemistry, we demonstrate that the density of Brønsted acid sites on the PtWO x /C inverse catalyst could be modulated by up to two orders of magnitude by altering the reaction parameters and by the chemistry itself. We elicit an order of magnitude increase in the acid-catalysed dehydration average reaction rate by periodic hydrogen pulsing. Metal–metal oxide inverse catalysts are an intriguing class of materials, although the understanding of their structure–activity properties remains elusive. Here, Vlachos and colleagues unravel the complex dynamic interplay between Brønsted acid and redox sites at the surface of a PtWO x /C inverse catalyst, offering a strategy to tune its acid-catalysed dehydration reactivity.

Proton conductivity of the polymer electrolyte membranes in fuel cells dictates their performance and requires sufficient water management. Here, we report a simple, scalable method to produce well-dispersed transition metal carbide nanoparticles. We demonstrate that these, when added as an additive to the proton exchange Nafion membrane, provide significant enhancement in power density and durability over 100 hours, surpassing both the baseline Nafion and platinum-containing recast Nafion membranes. Focused ion beam/scanning electron microscope tomography reveals the key membrane degradation mechanism. Density functional theory exposes that OH• and H• radicals adsorb more strongly from solution and reactions producing OH• are significantly more endergonic on tungsten carbide than on platinum. Consequently, tungsten carbide may be a promising catalyst in self-hydrating crossover gases while retarding desorption of and capturing free radicals formed at the cathode, resulting in enhanced membrane durability. The proton conductivity of polymer electrolyte membranes in fuel cells dictates their performance, but requires sufficient water management. Here, the authors report a simple method to produce well-dispersed transition metal carbide nanoparticles as additives to enhance the performance of Nafion membranes in fuel cells.

To investigate the repellent efficacy of commercially available mosquito repellents in China against Haemaphysalis longicornis, four representative DEET-based repellents and biont-derived repellents were selected. This study utilized a modified circular filter paper method repellent testing device to establish an evaluation system for assessing the repellent effects of each product against three developmental stages of H. longicornis: larvae, nymphs, and adults. In our study, for DEET-based repellents, Johnson demonstrated the highest repellency against larvae within 1 h, with an average repellency rate exceeding 80.14%. Yamei and Johnson exhibited repellency rates more than 91.11% for nymphs within 1 h, surpassing the other two DEET products. Repellency rates of Longliqi and Xiaohuanxiong fluctuated between 80.95% and 100% at different time points. Yamei, Longliqi, and Johnson achieved 100% repellency to adults within 1 h, while Xiaohuanxiong showed slightly lower efficacy. The four biont-derived repellents showed significant variations in efficacy: larval-stage repellency ranged from 14.29% to 88.89%, nymphal-stage repellency from 57.89% to 100%, and adult-stage repellency from 50% to 79.49%. CaliforniaBaby exhibited the highest efficacy, comparable or superior to DEET-based products, whereas Longhu demonstrated the weakest repellency and poor persistence. We further conducted a persistence test for CaliforniaBaby and found that it maintained >75% repellency against H. longicornis for 6 h. This study provides scientific evidence for selecting tick repellents in practice, offers guidance for purchasing commercial biont-derived tick repellents, and serves as a reference for developing safer, more effective tick repellents.

The supported Ru clusters with mean sizes ranging from 1.9 to 4.6 nm showed a high activity towards the NH3 decomposition reaction. The structural properties of catalysts were characterized by N2 adsorption/desorption, X-ray diffraction (XRD) and transmission electron micrograph (TEM). Steady-state reaction kinetics revealed that the apparent activation energy increased with a decrease in Ru particle size and ranged from 79 kJ mol−1 to 122 kJ mol−1. The decomposition rate over Ru nanoparticles showed a strong dependency on mean crystallite size and the optimum appeared at dRu = 2.2 nm. The dependencies of reaction rate on partial pressures of NH3 and H2 were also sensitive to the varying Ru particle size. Experimental data could be well fitted by the Temkin–Pyzhev equation, indicating that the recombinative desorption of surface nitrogen atom acts as the rate-determining step. A compensation effect between the pre-exponential factor (k0) and activation energy (Ea) was quantified.

Background Ticks can transmit numerous tick-borne pathogens and cause a huge economic loss to the livestock industry. Tick vaccines can contribute to the prevention of tick-borne diseases by inhibiting tick infestation or reproduction. Subolesin is an antigenic molecule proven to be a potential tick vaccine against different tick species and even some tick-borne pathogens. However, its effectivity has not been verified in Haemaphysalis longicornis , which is a widely distributed tick species, especially in East Asian countries. Therefore, the purpose of this study was to evaluate the effectivity of subolesin vaccination against H. longicornis in a rabbit model. Methods Haemaphysalis longicornis (Okayama strain, female, adult, parthenogenetic strain) and Japanese white rabbits were used as the model tick and animal, respectively. The whole open reading frame of H. longicornis subolesin (HlSu) was identified and expressed as a recombinant protein using E. coli . The expression was verified using sodium dodecyl sulfate polyacrylamide gel electrophoresis, and the immunogenicity of rHlSu against anti- H. longicornis rabbit serum was confirmed using Western blotting. After vaccination of rHlSu in rabbits, experimental infestation of H. longicornis was performed. Variables related to blood-feeding periods, pre-oviposition periods, body weight at engorgement, egg mass, egg mass to body weight ratio, and egg-hatching periods were measured to evaluate the effectiveness of subolesin vaccination. Results The whole open reading frame of HlSu was 540 bp, and it was expressed as a recombinant protein. Vaccination with rHlSu stimulated an immune response in rabbits. In the rHlSu-vaccinated group, body weight at engorgement, egg mass, and egg mass to body weight ratio were statistically significantly lower than those in the control group. Besides, egg-hatching periods were extended significantly. Blood-feeding periods and pre-oviposition periods were not different between the two groups. In total, the calculated vaccine efficacy was 37.4%. Conclusions Vaccination of rabbits with rHlSu significantly affected the blood-feeding and reproduction in H. longicornis . Combined with findings from previous studies, our findings suggest subolesin has the potential to be used as a universal tick vaccine.

Intangible cultural heritage is characterized by uniqueness, diversity, locality and ethnicity, and its integration into the narrative landscape design of theme parks is an important way for the inheritance and development of non-heritage culture. The article explores the narrative landscape design techniques used in theme parks and the types of narrative sequences used. Relying on the existing research, the evaluation index system of theme park narrative landscape design is established, the weights of evaluation indexes are solved by the entropy weighting method, and the EWM-TOPSIS model is combined with the TOPSIS method to realize the comprehensive evaluation of narrative landscape design. The satisfaction of narrative landscape design in theme parks in Province Y was analyzed using six theme parks as research objects. The evaluation index for narrative landscape design of theme parks found that aesthetic perceptibility had the most weight at 28.72%, while historical readability had the least weight at 14.27%. The comprehensive evaluation index of the theme park is the highest at 0.314, and the mean values of public satisfaction and importance for the theme park’s narrative intangible cultural heritage landscape design are 3.969 points and 4.049 points, respectively. Narrative landscape design for theme parks that celebrate intangible cultural heritage can help the public experience the charm of intangible cultural heritage.

Although vaccines are one of the environmentally friendly means to prevent the spread of ticks, there is currently no commercial vaccine effective against Haemaphysalis longicornis ticks. In this study, we identified, characterized, localized, and evaluated the expression patterns, and tested the immunogenic potential of a homologue of Rhipicephalus microplus ATAQ in H. longicornis (HlATAQ). HlATAQ was identified as a 654 amino acid-long protein present throughout the midgut and in Malpighian tubule cells and containing six full and one partial EGF-like domains. HlATAQ was genetically distant (homology < 50%) from previously reported ATAQ proteins and was expressed throughout tick life stages. Its expression steadily increased (p < 0.001) during feeding, reached a peak, and then decreased slightly with engorgement. Silencing of HlATAQ did not result in a phenotype that was significantly different from the control ticks. However, H. longicornis female ticks fed on a rabbit immunized with recombinant HlATAQ showed significantly longer blood-feeding periods, higher body weight at engorgement, higher egg mass, and longer pre-oviposition and egg hatching periods than control ticks. These findings indicate that the ATAQ protein plays a role in the blood-feeding-related physiological processes in the midgut and Malpighian tubules and antibodies directed against it may affect these tissues and disrupt tick engorgement and oviposition.