Calcium Single Atom Confined in Nitrogen-Doped Carbon-Coupled Polyvinylidene Fluoride Membrane for High-Performance Piezocatalysis.

A piezoelectric polymer membrane based on single metal atoms was demonstrated to be effective by anchoring isolated calcium (Ca) atoms on a composite of nitrogen-doped carbon and polyvinylidene fluoride (PVDF). The addition of Ca-atom-anchored carbon nanoparticles not only promotes the formation of the ß phase (from 29.8 to 56.3%), the most piezoelectrically active phase, in PVDF, but also introduces much higher porosity and hydrophilicity. Under ultrasonic excitation, the fabricated catalyst membrane demonstrates a record-high and stable dye decomposing rate of 0.11 min-1 and antibacterial efficiencies of 99.8%. Density functional theory calculations reveal that the primary contribution to catalytic activity arises from single-atom Ca doping and that a possible synergistic effect between PVDF and Ca atoms can improve the catalytic performance. It is shown that O2 molecules can be easily hydrogenated to produce ·OH on Ca-PVDF, and the local electric field provided by the ß-phase-PVDF might enhance the production of ·O2-. The proposed polymer membrane is expected to inspire the rational design of piezocatalysts and pave the way for the application of piezocatalysis technology for practical environmental remediation.

A Q-learning method based on coarse-to-fine potential energy surface for locating transition state and reaction pathway.

Transition state (TS) on the potential energy surface (PES) plays a key role in determining the kinetics and thermodynamics of chemical reactions. Inspired by the fact that the dynamics of complex systems are always driven by rare but significant transition events, we herein propose a TS search method in accordance with the Q-learning algorithm. Appropriate reward functions are set for a given PES to optimize the reaction pathway through continuous trial and error, and then the TS can be obtained from the optimized reaction pathway. The validity of this Q-learning method with reasonable settings of Q-value table including actions, states, learning rate, greedy rate, discount rate, and so on, is exemplified in 2 two-dimensional potential functions. In the applications of the Q-learning method to two chemical reactions, it is demonstrated that the Q-learning method can predict consistent TS and reaction pathway with those by ab initio calculations. Notably, the PES must be well prepared before using the Q-learning method, and a coarse-to-fine PES scanning scheme is thus introduced to save the computational time while maintaining the accuracy of the Q-learning prediction. This work offers a simple and reliable Q-learning method to search for all possible TS and reaction pathway of a chemical reaction, which may be a new option for effectively exploring the PES in an extensive search manner.

Regioselective C3Alkylation of Indoles for the Synthesis of Bis(indolyl)methanes and 3-Styryl Indoles.

Herein, we describe an efficient transition-metal-free regioselective C3alkylation of indoles for the synthesis of bis(indolyl)methanes and 3-styryl indoles. Nitrobenzene is employed as the oxidant to oxidize the alcohols in the presence of a strong base and the reaction avoids the use of transition metals such as Ru and Mn. The protocol provides a favorable route to access biologically active compounds such as arundine, vibrindole A, and turbomycin B.

Abundance and sources of particulate polycyclic aromatic hydrocarbons and aromatic acids at an urban site in central China.

We conducted a simultaneous field study of PM2.5-bound particulate polycyclic aromatic hydrocarbons (PAHs) and aromatic acids (AAs) in a polluted city Zhengzhou to explore the concentration, sources and potential conversion pathways between PAHs and AAs in different seasons. The average concentrations of PM2.5, 28PAHs and 8AAs during the sampling period were 77 µg/m3, 75 ng/m3, and 283 ng/m3, respectively. The concentration of both 28PAHs and 8AAs were highest in winter and lowest in summer with ratios of 6.3 and 2.3, respectively. PAHs with 5-7 rings were the main components of PAHs (52%), followed by 4 rings PAHs (30%) and 2-3 rings PAHs (18%). According to the source appointment results obtained by positive matrix factorization, the main sources of PAHs were combustion and vehicle emissions, which account for 37% and 34%, respectively. 8AAs were divided into three groups, including four benzene dicarboxylic acids (B2CAs), three benzene tricarboxylic acids (B3CAs) and one benzene tetracarboxylic acid (B4CA). And interspecies correlation analysis with PM2.5 source markers were used to investigate potential sources. Phthalic acid (o-Ph) was the most abundant specie of 8AAs (157 ng/m3, 55% of 8AAs), which was well correlated with sulfate. Meanwhile, B3CAs and B4CA were highly correlated with sulfate and weakly correlated with levoglucosan, suggesting that secondary formation was their main source. As logical oxidation products of PAHs, o-Ph and B3CAs showed good correlations with a number of PAHs, indicating possible photochemical oxidation pathway by PAHs. In addition, O3, NO2, temperature and relative humidity have positive effects on the secondary formation of B3CAs.

Ternary Rotational Polyanion Coupling Enables Fast Li Ion Dynamics in Tetrafluoroborate Ion Doped Antiperovskite Li2OHCl Solid Electrolyte.

Li-rich antiperovskite (LiRAP) hydroxyhalides are emerging as attractive solid electrolyte (SEs) for all-solid-state Li metal batteries (ASSLMBs) due to their low melting point, low cost, and ease of scaling-up. The incorporation of rotational polyanions can reduce the activation energy and thus improve the Li ion conductivity of SEs. Herein, we propose a ternary rotational polyanion coupling strategy to fasten the Li ion conduction in tetrafluoroborate (BF4 -) ion doped LiRAP Li2OHCl. Assisted by first-principles calculation, powder X-ray diffraction, solid-state magnetic resonance and electrochemical impedance spectra, it is confirmed that Li ion transport in BF4 - ion doped Li2OHCl is strongly associated with the rotational coupling among OH-, BF4 - and Li2-O-H octahedrons, which enhances the Li ion conductivity for more than 1.8 times with the activation energy lowering 0.03 eV. This work provides a new perspective to design high-performance superionic conductors with multi-polyanions.

Engineering of cyclodextrin glycosyltransferase improves the conversion efficiency of rebaudioside A to glucosylated steviol glycosides and increases the content of short-chain glycosylated steviol glycoside.

BACKGROUND: Compared with steviol glycosides, the taste of glucosylated steviol glycosides is better and more similar to that of sucrose. At present, cyclodextrin glucanotransferase (CGTase) is primarily used to catalyze the conversion of steviol glycosides to glucosylated steviol glycosides, with soluble starch serving as a glycosyl donor. The main disadvantages of enzymatic transglycosylation are the limited number of enzymes available, the low conversion rates that result in low yields, and the lack of selectivity in the degree of glycosylation of the products. In order to fill these gaps, the proteome of Alkalihalobacillus oshimensis (also named Bacillus oshimensis) was used for mining novel CGTases. RESULTS: Here, CGTase-15, a novel ß-CGTase with a wide pH adaptation range, was identified and characterized. The catalyzed product of CGTase-15 tasted better than that of the commercial enzyme (Toruzyme® 3.0 L). In addition, two amino acid sites, Y199 and G265, which play important roles in the conversion of steviol glycosides to glucosylated steviol glycosides were identified by site-directed mutagenesis. Compared with CGTase-15, CGTase-15-Y199F mutant significantly increased the conversion rate of rebaudioside A (RA) to glucosylated steviol glycosides. Compared with CGTase-15, the content of short-chain glycosylated steviol glycosides catalyzed by CGTase-15-G265A mutant was significantly increased. Moreover, the function of Y199 and G265 was verified in other CGTases. The above mutation pattern has also been applied to CGTase-13 (a CGTase discovered by our laboratory with great potential in the production of glycosylated steviol glycosides), confirming that the catalytic product of CGTase-13-Y189F/G255A mutant has a better taste than that of CGTase-13. CONCLUSIONS: This is the first report on the improvement of the sensory profiles of glycosylated steviol glycosides through site-directed mutagenesis of CGTase, which is significant for the production of glycosylated steviol glycosides.

Optimization of chemical synthesis with heuristic algorithms.

Optimizing reaction conditions to improve the yield is fundamental for chemical synthesis and industrial processes. Experiments can only be performed under a small portion of reaction conditions for a system, so a strategy of experimental design is required. Bayesian optimization, a global optimization algorithm, was found to outperform human decision-making in reaction optimization. Similarly, heuristic algorithms also have the potential to solve optimization problems. In this work, we optimize these reaction conditions for Buchwald-Hartwig and Suzuki systems by predicting reaction yields with three heuristic algorithms and three encoding methods. Our results demonstrate that particle swarm optimization with numerical encoding is better than the genetic algorithm or simulated annealing. Moreover, its performance is comparable to Bayesian optimization without the computational costs of descriptors. Particle swarm optimization is simple and easy to perform, and it can be implemented into laboratory practice to promote chemical synthesis.

Self-isomerization of nearly planar superatoms formed by actinide embedded gold clusters.

First-principles calculations show a self-isomerization process of the nearly planar superatom, in which the maximum energy difference between different extreme points is below 0.1 eV and a crossing between singlet and triplet states is also involved. Further UV-Vis spectra reveal a correlation between the spectra and structures caused by self-isomerization.

Emission characteristics and light absorption apportionment of carbonaceous aerosols: A tunnel test conducted in an urban with fully enclosed use of E10 petrol.

To reduce the heavy dependence on petroleum, bioethanol has been increasingly employed as an alternative and sustainable transportation fuel. However, the characteristics of black carbon (BC) emissions from E10 petrol vehicles (i.e., ethanol-gasoline containing 10% ethanol) are still unclear, especially under real driving conditions. Here, a tunnel test was conducted during a cold winter. This tunnel was characterized by heavy traffic comprising more than 98% E10-fueled gasoline vehicles (GVs). Real-time BC concentrations, traffic parameters and meteorological conditions were recorded during the sampling campaign. The average BC concentration inside the tunnel (10.94 ± 5.02 µg m-3) was almost twice the background concentration. Based on aethalometer AE33 in situ measurements and the minimum R-squared (MRS) method, real-time aerosol light absorption was apportioned. The light absorption proportions of BC, primary brown carbon (BrC1) and secondary brown carbon (BrC2) were 79.86%, 2.78% and 17.36%, respectively, at 370 nm. The BC emission factor (EFBC) of the E10-fueled vehicles was 1.09 ± 0.49 mg km-1·veh-1 and 15.24 ± 6.85 mg·(kg fuel)-1, lower than those of traditional gasoline fueled vehicles in previous studies. This study can support the compilation of vehicular BC emission inventories, provide recommendations for biofuel policies and contribute to comprehensively understanding the climatic impact of E10 petrol.

Higher-order Rayleigh-quotient gradient effect on electron correlations.

The incomplete understanding of electron correlation is still profound due to the lack of exact solutions of the Schrödinger equation of many electron systems. In this work, we present the correlation-induced changes in the calculated many-electron systems beyond the standard residual. To locate the minimum of the Rayleigh quotient, each iteration is to seek the lowest eigenpairs in a subspace spanned by the current wave function and its gradient of the Rayleigh-quotient as well as the upcoming higher-order residual. Consequently, as the upcoming errors can be introduced and circumvented with the search in the higher-order residual, a concomitant improved performance in terms of number of iterations, convergence rate, and total elapsed time is very significant. The correlation energy components obtained with the original residual are corrected with the higher-order residual application, satisfying the correlation virial theorem with much improved accuracy. The comparison with the original residual, the higher-order residual significantly improves the electron binding, favoring the localization of electrons' distribution, revealed with the increasing peak of the distribution and correlation function and the reduced interelectron distance and its angle.

Air pollution prevention in central China: Effects on particulate-bound PAHs from 2010 to 2018.

Long-term trends in particulate-bound polycyclic aromatic hydrocarbon (PAH) concentrations in air in Zhengzhou (a severely polluted city in central China) between 2010 and 2018 were studied to assess the effectiveness of an air pollution prevention and control action plan (APPCAP) implemented in 2013. The PM2.5, sum of 16 PAHs (Σ16 PAHs), benzo[a]pyrene (BaP), and BaP toxic equivalent concentrations were high before 2013 but 41%, 77%, 77%, and 78% lower, respectively, after the APPCAP. The maximum daily Σ16 PAHs concentration between 2014 and 2018 was 338 ng/m3, 65% lower than the maximum of 961 ng/m3 between 2010 and 2013. The ratio between the Σ16 PAHs concentrations in winter and summer decreased over time and was 8.0 in 2011 and 1.5 in 2017. The most abundant PAH was benzo[b]fluoranthene, for which the 9-year mean concentration was 14 ± 21 ng/m3 (15% of the Σ16 PAHs concentration). The mean benzo[b]fluoranthene concentration decreased from 28 ± 27 ng/m3 before to 5 ± 4 ng/m3 after the APPCAP (an 83% decrease). The mean daily BaP concentrations were 0.1-62.8 ng/m3, and >56% exceeded the daily standard limit of 2.5 ng/m3 for air. The BaP concentration decreased from 10 ± 8 ng/m3 before to 2 ± 2 ng/m3 after the APPCAP (a 77% decrease). Diagnostic ratios and positive matrix factorization model results indicated that coal combustion and vehicle exhausts were important sources of PAHs throughout the study period, contributing >70% of the Σ16 PAHs concentrations. The APPCAP increased the relative contribution of vehicle exhausts from 29% to 35% but decreased the Σ16 PAHs concentration attributed to vehicle exhausts from 48 to 12 ng/m3. The PAH concentration attributed to vehicle exhausts decreased by 79% even though vehicle numbers strongly increased, indicating that pollution caused by vehicles was controlled well. The relative contribution of coal combustion remained stable but the PAH concentration attributed to coal combustion decreased from 68 ng/m3 before to 13 ng/m3 after the APPCAP. Vehicles made dominant contributions to the incremental lifetime cancer risk (ILCRs) before and after the APPCAP even though the APPCAP decreased the ILCRs by 78%. Coal combustion was the dominant source of PAHs but contributed only 12-15% of the ILCRs. The APPCAP decreased PAH emissions and changed the contributions of different sources of PAHs, and thus strongly affected the overall toxicity of PAHs to humans.

Contributions of local emissions and regional background to summertime ozone in central China.

Source contributions and regional transport of maximum daily average 8-h (MDA8) O3 during a high O3 month (June 2019) in Henan province in central China are explored using a source-oriented Community Multiscale Air Quality (CMAQ) model. The monthly average MDA8 O3 exceeds ∼70 ppb in more than half of the areas and shows a clear spatial gradient, with lower O3 concentrations in the southwest and higher in the northeast. Significant contributions of anthropogenic emissions to monthly average MDA8 O3 concentrations of more than 20 ppb are predicted in the provincial capital Zhengzhou, mostly due to emissions from the transportation sector (∼50%) and in the areas in the north and northeast regions where industrial and power generation-related emissions are high. Biogenic emissions in the region only contribute to approximately 1-3 ppb of monthly average MDA8 O3. In industrial areas north of the province, their contributions reach 5-7 ppb. Two CMAQ-based O3-NOx-VOCs sensitivity assessments (the local O3 sensitivity ratios based on the direct decoupled method and the production ratio of H2O2 to HNO3) and the satellite HCHO to NO2 column density ratio consistently show that most of the areas in Henan are in NOx-limited regime. In contrast, the high O3 concentration areas in the north and at the city centers are in the VOC-limited or transition regimes. The results from this study suggest that although reducing NOx emissions to reduce O3 pollution in the region is desired in most areas, VOC reductions must be applied to urban and industrial regions. Source apportionment simulations with and without Henan anthropogenic emissions show that the benefit of local anthropogenic NOx reduction might be lower than expected from the source apportionment results because the contributions of Henan background O3 increase in response to the reduced local anthropogenic emissions due to less NO titration. Thus, collaborative O3 controls in neighboring provinces are needed to reduce O3 pollution problems in Henan effectively.

Efficient Bioconversion of Stevioside and Rebaudioside A to Glucosylated Steviol Glycosides Using an Alkalihalobacillus oshimesis-Derived Cyclodextrin Glucanotransferase.

The enzymatic transglycosylation of steviol glycosides can improve the edulcorant quality of steviol glycosides. Cyclodextrin glucanotransferase (CGTase) is one of the most popular glucanotransferases applied in this reaction. Herein, the CGTase-producing strain Alkalihalobacillus oshimensis CGMCC 23164 was isolated from Stevia planting soil. Using mass spectrometry-based secretome profiling, a high-efficiency CGTase that converted steviol glycosides to glucosylated steviol glycosides was identified and termed CGTase-13. CGTase-13 demonstrated optimal transglycosylation activity with 10 g/L steviol glycoside and 50 g/L soluble starch as substrates at <40 °C. Under the above conditions, the conversion rate of stevioside and rebaudioside A, two main components of steviol glycosides, reached 86.1% and 90.8%, respectively. To the best of our knowledge, this is the highest conversion rate reported to date. Compared with Toruzyme® 3.0 L, the commonly used commercial enzyme blends, glucosylated steviol glycosides produced using CGTase-13 exhibited weaker astringency and unpleasant taste, faster sweetness onset, and stronger sweetness intensity. Thus, CGTase provides a novel option for producing high-quality glucosylated steviol glycoside products and has great potential for industrial applications.

Gastrodin and Gastrodigenin Improve Energy Metabolism Disorders and Mitochondrial Dysfunction to Antagonize Vascular Dementia.

Vascular dementia (VD) is the second most common dementia syndrome worldwide, and effective treatments are lacking. Gastrodia elata Blume (GEB) has been used in traditional Chinese herbal medicine for centuries to treat cognitive impairment, ischemic stroke, epilepsy, and dizziness. Gastrodin (p-hydroxymethylphenyl-b-D-glucopyranoside, Gas) and Gastrodigenin (p-hydroxybenzyl alcohol, HBA) are the main bioactive components of GEB. This study explored the effects of Gas and HBA on cognitive dysfunction in VD and their possible molecular mechanisms. The VD model was established by bilateral common carotid artery ligation (2-vessel occlusion, 2-VO) combined with an intraperitoneal injection of sodium nitroprusside solution. One week after modeling, Gas (25 and 50 mg/kg, i.g.) and HBA (25 and 50 mg/kg, i.g.) were administered orally for four weeks, and the efficacy was evaluated. A Morris water maze test and passive avoidance test were used to observe their cognitive function, and H&E staining and Nissl staining were used to observe the neuronal morphological changes; the expressions of Aß1-42 and p-tau396 were detected by immunohistochemistry, and the changes in energy metabolism in the brain tissue of VD rats were analyzed by targeted quantitative metabolomics. Finally, a Hippocampus XF analyzer measured mitochondrial respiration in H2O2-treated HT-22 cells. Our study showed that Gas and HBA attenuated learning memory dysfunction and neuronal damage and reduced the accumulation of Aß1-42, P-Tau396, and P-Tau217 proteins in the brain tissue. Furthermore, Gas and HBA improved energy metabolism disorders in rats, involving metabolic pathways such as glycolysis, tricarboxylic acid cycle, and the pentose phosphate pathway, and reducing oxidative damage-induced cellular mitochondrial dysfunction. The above results indicated that Gas and HBA may exert neuroprotective effects on VD by regulating energy metabolism and mitochondrial function.

Charge Transfer Doping of Carbon Nitride Films through Noncovalent Iodination for Enhanced Photoelectrochemical Performance: Combined Experimental and Computational Insights.

To improve the photoelectrochemical (PEC) performance of photocatalysts, the doping strategy through covalent functionalization is often adopted to adjust material electronic structures. By contrast, this work demonstrates that the noncovalent interaction in the case of iodinated graphitic carbon nitride (g-CN) film can also enhance the PEC performance. Through a facile synthesis method of rapid thermal vapor condensation (RTVC), the prepared iodinated g-CN film shows a significantly improved photocurrent density (38.9 µA cm-2 ), three times that of pure g-CN film (13.0 µA cm-2 ) at 1.23 V versus reversible hydrogen electrode. Computations reveal that the noncovalent attachment of iodine anion (I- ) on g-CN plays a crucial role in modulating the bandgap states and broadening of the visible-light absorption range as well as the charge carrier separation with the photo-induced hole confined to I- and electron to g-CN film. The fully filled valence orbitals (4d10 5s2 5p6 ) of I- determine its noncovalent attachment on the g-CN film and so do the iodine species of I3 - , I5 - , etc. This work offers a favorable synthesis method to achieve efficient doping through noncovalent charge transfer between thin film and certain dopants and provides a useful modification strategy for the establishment of multi-channel transportation of charge carriers in general photocatalysts.

Role of the A-Element in the Structural, Mechanical, and Electronic Properties of Ti3AC2 MAX Phases.

Combining metallic and ceramic properties, and as precursors for MXenes, MAX phases have attracted extensive attention. In recent years, A-element substitution has been demonstrated as an effective scheme to enrich the MAX family. To explore more possible MAX members, the structural, mechanical, and electronic properties and stabilities of 31 Ti3AC2 (A = Al, Si, P, S, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Os, Ir, Pt, Au, Hg, TI, Pb, Bi, and Po) configurations are investigated in this work. Moreover, the interfacial strength implicating the possibility of exfoliating MAX into MXenes is examined. The A-element plays a crucial role in the lattice parameters and mechanical strength of Ti3AC2, and their variations are well explained by the synergistic effects of d-d and p-d hybridizations between the valence orbitals of Ti and A. Ti3SC2 presents the largest Young's modulus of 360 GPa, which is 6.82% higher than that in the well-studied Ti3SiC2. Ti3SbC2 is a mechanical quasi-isotropic configuration. After checking the mechanical, dynamical, and thermodynamic stability, Ti3AC2 (A = Al, Si, P, S, Ga, Ge, As, Cd, In, Sn, Sb, Au, Hg, Pb, TI, and Po) are stable, while Ti3AC2 (A = Fe, Co, Zn, Se, Ru, Rh, Pd, Ag, Te, Ir, Pt, and Bi) are metastable. Compared to Ti3AlC2, Ti3AC2 (A = Ag, Sb, Te, Bi, and Po) exhibit much lower interfacial strength in Ti-A interfaces and larger ratios between the interfacial strengths of neighboring Ti-C and Ti-A interfaces. This implies that these configurations are promising precursors for the synthesis of Ti3C2Tx (Tx denotes surface groups) with a large flake size. All of the configurations are metallic, and Ti3AC2 (A = Fe and Co) are magnetic. Based on the phonon dispersion and electronic structure, these Ti3AC2 configurations might have potential applications in phononic crystals and topological materials.

Steric Hindrance Governs the Photoinduced Structural Planarization of Cycloparaphenylene Materials.

Cycloparaphenylenes ([n]CPPs) and their derivatives are known for the unique size-dependent photophysical properties, which are largely attributed to the structural planarization-associated exciton localization, attracting substantial research attention. In this work, we show that the steric hindrance between neighboring structural units plays a key role in governing the photoinduced global/local structural planarization and electron-hole distribution features of [n]CPP materials, due to the tunable strength of H···H repulsion between neighboring units via structural modification or C-H distance variation as revealed by density functional theory (DFT) and time-dependent DFT calculations. According to our results, steric hindrance controls the manner and also the extent of excited-state structural planarization, where a weak (strong) steric hindrance favors (hinders) structural planarization upon relaxation in the first excited singlet (S1) state as compared to the ground (S0)-state structure. Depending on the molecular structures, steric hindrance leads to fully delocalized, partially separated, or more localized electron-hole distributions. For example, via H···H repulsion release by manually shortening the C-H distance or by chemical substitution of C-H with N atoms, the modified [10]CPP structures show fully planarized configurations (each dihedral angle can be less than 2°) and entirely delocalized electron-hole distribution upon photorelaxation. This work provides insights into the structural origin of the unusual photophysical properties of [n]CPPs and shows the promise of steric hindrance tuning in accessing diverse excited-state features in [n]CPP materials.

Effects of Cu doping on electrochemical NOx removal by La0.8Sr0.2MnO3 perovskites.

Electrochemical removal of nitrogen oxides (NOx) by perovskite electrodes is a promising method due to its low cost, simple operation and no secondary pollution. In this study, a series of La0.8Sr0.2Mn1-xCuxO3 (x = 0, 0.05, 0.1 and 0.15) perovskites are fabricated as the improved electrodes of solid electrolyte cells (SECs) for NOx removal and the effects of Cu doping are investigated systematacially. Multiple characterization methods are carried out to analyze the physicochemical properties of perovskites firstly. Then the performances of cells based on various perovskites are evaluated by the measurements of electrochemical properties and NOx conversions. The results show that the Cu-doped electrode has more surface oxygen vacancies and a better redox property, thus having a higher NOx conversion and smaller polarization resistance. The electrode based on La0.8Sr0.2Mn0.9Cu0.1O3 has the maximum 70.8% NOx conversion and the lowest 36.3 Ω cm2 Rp value in the atmosphere of 1000 ppm NO at 700 °C. First-principle calculation reveals that the Cu-doped electrode is easier to form surface oxygen vacancy, while the surface oxygen vacancy plays an important role on electron transfer between electrode and NOx molecule. This study not only provides a new strategy to enhance the electrode performance for NOx removal in SECs but reveals the fundamental effect of Cu doping on the properties of La0.8Sr0.2MnO3 perovskites.

Spent LiFePO4: An old but vigorous peroxymonosulfate activator for degradation of organic pollutants in water.

Iron-based catalysts have been demonstrated to activate peroxymonosulfate (PMS) to generate reactive radicals, which is however limited by their complex preparation process, high costs and inefficiency for practical applications. Herein we obtain spent LiFePO4 (SLFP), with powerful catalytic capacity by a simple one-step treatment of the retired LiFePO4 cathode material, for PMS activation to decontaminate organic pollutants. Lithium defects and oxygen vacancies in SLFP play critical roles for PMS utilization, further confirmed by density functional theory (DFT) calculations. SLFP materials rapidly adsorb PMS, and the surface PMS is activated by Fe(II) to generate radicals, with •OH playing a major role for the degradation of organics after multi-step reactions. The SLFP/PMS process is finally validated for ability to remove organic contaminants and potential environmental application.

Fungal cellulases: protein engineering and post-translational modifications.

Enzymatic degradation of lignocelluloses into fermentable sugars to produce biofuels and other biomaterials is critical for environmentally sustainable development and energy resource supply. However, there are problems in enzymatic cellulose hydrolysis, such as the complex cellulase composition, low degradation efficiency, high production cost, and post-translational modifications (PTMs), all of which are closely related to specific characteristics of cellulases that remain unclear. These problems hinder the practical application of cellulases. Due to the rapid development of computer technology in recent years, computer-aided protein engineering is being widely used, which also brings new opportunities for the development of cellulases. Especially in recent years, a large number of studies have reported on the application of computer-aided protein engineering in the development of cellulases; however, these articles have not been systematically reviewed. This article focused on the aspect of protein engineering and PTMs of fungal cellulases. In this manuscript, the latest literatures and the distribution of potential sites of cellulases for engineering have been systematically summarized, which provide reference for further improvement of cellulase properties. KEY POINTS: •Rational design based on virtual mutagenesis can improve cellulase properties. •Modifying protein side chains and glycans helps obtain superior cellulases. •N-terminal glutamine-pyroglutamate conversion stabilizes fungal cellulases.