Barrierless reactions of C2 Criegee intermediates with H2SO4 and their implication to oligomers and new particle formation.

The formation of oligomeric hydrogen peroxide triggered by Criegee intermediate maybe contributes significantly to the formation and growth of secondary organic aerosol (SOA). However, to date, the reactivity of C2 Criegee intermediates (CH3CHOO) in areas contaminated with acidic gas remains poorly understood. Herein, high-level quantum chemical calculations and Born-Oppenheimer molecular dynamics (BOMD) simulations are used to explore the reaction of CH3CHOO and H2SO4 both in the gas phase and at the air-water interface. In the gas phase, the addition reaction of CH3CHOO with H2SO4 to generate CH3HC(OOH)OSO3H (HPES) is near-barrierless, regardless of the presence of water molecules. BOMD simulations show that the reaction at the air-water interface is even faster than that in the gas phase. Further calculations reveal that the HPES has a tendency to aggregate with sulfuric acids, ammonias, and water molecules to form stable clusters, meanwhile the oligomerization reaction of CH3CHOO with HPES in the gas phase is both thermochemically and kinetically favored. Also, it is noted that the interfacial HPES- ion can attract H2SO4, NH3, (COOH)2 and HNO3 for particle formation from the gas phase to the water surface. Thus, the results of this work not only elucidate the high atmospheric reactivity of C2 Criegee intermediates in polluted regions, but also deepen our understanding of the formation process of atmospheric SOA induced by Criegee intermediates.

Ultrafast transient absorption spectra and kinetics of human blue cone visual pigment at room temperature.

The ultrafast photochemical reaction mechanism, transient spectra, and transition kinetics of the human blue cone visual pigment have been recorded at room temperature. Ultrafast time-resolved absorption spectroscopy revealed the progressive formation and decay of several metastable photo-intermediates, corresponding to the Batho to Meta-II photo-intermediates previously observed with bovine rhodopsin and human green cone opsin, on the picosecond to millisecond timescales following pulsed excitation. The experimental data reveal several interesting similarities and differences between the photobleaching sequences of bovine rhodopsin, human green cone opsin, and human blue cone opsin. While Meta-II formation kinetics are comparable between bovine rhodopsin and blue cone opsin, the transition kinetics of earlier photo-intermediates and qualitative characteristics of the Meta-I to Meta-II transition are more similar for blue cone opsin and green cone opsin. Additionally, the blue cone photo-intermediate spectra exhibit a high degree of overlap with uniquely small spectral shifts. The observed variation in Meta-II formation kinetics between rod and cone visual pigments is explained based on key structural differences.

Native ß-barrel substrates pass through two shared intermediates during folding on the BAM complex.

The assembly of ß-barrel proteins into membranes is mediated by the evolutionarily conserved ß-barrel assembly machine (BAM) complex. In Escherichia coli, BAM folds numerous substrates which vary considerably in size and shape. How BAM is able to efficiently fold such a diverse array of ß-barrel substrates is not clear. Here, we develop a disulfide crosslinking method to trap native substrates in vivo as they fold on BAM. By placing a cysteine within the luminal wall of the BamA barrel as well as in the substrate ß-strands, we can compare the residence time of each substrate strand within the BamA lumen. We validated this method using two defective, slow-folding substrates. We used this method to characterize stable intermediates which occur during folding of two structurally different native substrates. Strikingly, these intermediates occur during identical stages of folding for both substrates: soon after folding has begun and just before folding is completed. We suggest that these intermediates arise due to barriers to folding that are common between ß-barrel substrates, and that the BAM catalyst is able to fold so many different substrates because it addresses these common challenges.

Hydrogen-Bonded Complexes of HPN• and HNP• Radicals with Carbon Monoxide.

Phosphorus mononitride (PN) is a carrier of phosphorus in the interstellar medium. As the simplest derivatives of PN, the radical species HPN• and HNP• have remained elusive. Herein, we report the generation, characterization, and photochemistry of HPN• and HNP• in N2-matrix at 3 K. Specifically, HPN• was formed as a weakly bonded complex with CO in the matrix by 254 nm photolysis of the novel phosphinyl radical HPNCO•. The •NPH-CO complex is extremely unstable, as it undergoes spontaneous isomerization to the lower-energy isomer •PNH-CO through fast quantum mechanical tunneling (QMT) with a half-life of 6.1 min at 3 K. Upon further irradiation at 254 nm, the reverse conversion of •PNH-CO to •NPH-CO along with dehydrogenation to yield PN was observed. The characterization •NPH-CO and •PNH-CO with matrix-isolation IR spectroscopy is supported by D, 15N, and 13C isotope labeling and quantum chemical calculations at the XYGJ-OS/AVTZ level of theory, and the mechanism by hydrogen atom tunneling is consistent with multidimensional instanton theory calculations.

Tailoring the d-Band Center of WS2 by Metal and Nonmetal Dual-Doping for Enhanced Electrocatalytic Nitrogen Reduction.

Tuning the adsorption energy of nitrogen intermediates and lowering the reaction energy barrier is essential to accelerate the kinetics of nitrogen reduction reaction (NRR), yet remains a great challenge. Herein, the electronic structure of WS2 is tailored based on a metal and nonmetal dual-doping strategy (denoted Fe, F-WS2) to lower the d-band center of W in order to optimize the adsorption of nitrogen intermediates. The obtained Fe, F-WS2 nanosheet catalyst presents a high Faradic efficiency (FE) of 22.42% with a NH3 yield rate of 91.46 µg h-1 mgcat. -1. The in situ characterizations and DFT simulations consistently show the enhanced activity is attributed to the downshift of the d-band center, which contributes to the rate-determining step of the second protonation to form N2H2 * key intermediates, thereby boosting the overall nitrogen electrocatalysis reaction kinetics. This work opens a new avenue to enhanced electrocatalysis by modulating the electronic structure and surrounding microenvironment of the catalytic metal centers.

MoS2 coupled with ball milling co-modified sludge biochar to efficiently activate peroxymonosulfate for neonicotinoids degradation: Dominant roles of SO4•-, 1O2 and surface-bound radicals.

An efficient catalyst of molybdenum disulfide (MoS2) coupled with ball milling modified sludge biochar (BMSBC) was prepared to efficiently activate peroxymonosulfate (PMS) for neonicotinoids elimination. As expected, 95.1% of imidacloprid (IMI) was degraded by PMS/BMSBC system within 60 min and it was accompanied by the outstanding mineralization rate of 71.9%. The superior pore structures, rich defects, oxygen-containing functional groups and grafted MoS2 on BMSBC offered excellent activation performance for PMS. The influencing factor experiments demonstrated that PMS/BMSBC system performed high anti-interference to wide pH range and background constituents (e.g., inorganic ions and humic acid). Quenching experiments and electron paramagnetic resonance analysis revealed that SO4•-, 1O2, and surface-bound radicals played critical roles in IMI degradation. Electron donors on biochar activated PMS, producing surface radicals. The lone pair electrons within the Lewis basic site of C=O on BMSBC enhanced PMS decomposition by facilitating the cleavage of the -O-O- bond in PMS to release 1O2. The activation process of PMS by MoS2 accelerated the oxidation of Mo (IV) to Mo (VI) to generate SO4•-. Based on the transformed products (TPs), four degradation pathways of IMI in PMS/BMSBC system were suggested, and all TPs toxicity levels were lower than that of IMI by ECOSAR analysis. Additionally, BMSBC exhibited outstanding sustainable catalytic activity towards PMS activation with the well accepted degradation rate of 71.3% for IMI even after five reuse cycles. PMS/BMSBC system also exhibited satisfactory degradation rates (>71.8%) for IMI in various real waters (e.g., sewage effluent and livestock wastewater). Furthermore, PMS/BMSBC system also offered a favorable broad-spectrum elimination performance for other typical neonicotinoids (e.g., thiamethoxam, clothianidin, thiacloprid) with the degradation rates over 98%. This study has developed a desirable neonicotinoids purification technology in view of its high degradation/mineralization rate, outstanding detoxification performance, satisfied anti-interference to ambient conditions and sustainable sludge management.

Insights into the photosensitivity and photobleaching of dissolved organic matter from microplastics: Structure-activity relationship and transformation mechanism.

Revealing the structure-activity relationship between physicochemical properties and photoactivities of microplastic dissolved organic matter (MPDOM) is significant for understanding the environmental fate of MPs. Here, we systematically analyzed the physicochemical properties and molecular composition of DOM derived from MPs including polystyrene (PS), polyethylene glycol terephthalate (PET), polyadipate/butylene terephthalate (PBAT), polylactic acid (PLA), polypropylene (PP), and compared their photosensitivity and photobleaching behaviors. Results indicated that PSDOM and PETDOM had more similar properties and compositions, and showed stronger photosensitivity and photobleaching effects than PBATDOM, PLADOM and PPDOM. The [3DOM∗]SS and [1O2]SS varied in the range of 0.31-13.03 × 10-14 and 1.71-5.49 × 10-13 M, respectively, which were within the reported range of DOM from other sources. The SUVA254, HIX, AImodwa, Xcwa and lignin/CRAM-like component showed positive correlation with the [3DOM∗]SS, [1O2]SS and Φ3DOM*. The negative correlation between E2/E3 and [3DOM∗]SS was due to the higher proportion of low-molecular weight components in MPDOM. The lignin/CRAM-like component was identified to be the crucial photobleaching-component. The lignin/CRAM-like in PSDOM showed a deepened oxidation degree, while its change trend in PETDOM was from unsaturated to saturated. These findings provide new insights into the relevant photochemical fate of MPDOM.

Approaches to determination of the mechanism of the Rieske monooxygenase salicylate 5-hydroxylase.

Rieske oxygenases catalyze an exceptionally broad range of discrete types of reactions despite the utilization of a highly conserved quaternary structure and metal cofactor complement. Oxygen activation within this family occurs at a mononuclear FeII site, which is located approximately 12 Å from a one-electron reduced Rieske-type iron-sulfur cluster. Electron transfer from the Rieske cluster to the mononuclear iron site occurs during O2 activation and product formation. A key question is whether all Rieske oxygenase reactions involve the same type of activated oxygen species. This question has been explored using the Rieske oxygenase salicylate 5-hydroxylase, which catalyzes both aromatic hydroxylation of salicylate and aromatic methyl hydroxylation when a methyl substituent is placed in the normal position of aromatic ring hydroxylation. We show here that the combined application of kinetic, biophysical, computational, and isotope effect methods reveals a uniform mechanism for initial O2 activation and substrate attack for both types of reactivity. However, the mechanism diverges during the later phases of the reactions in response to the electronic nature and geometry of the substrates as well as the lifetime of intermediates. Similar factors may be encountered broadly in the Rieske oxygenase family.

Metabolic signatures of metabolites of the purine degradation pathway in human plasma using HILIC UHPLC-HRMS.

The metabolic disorders in the purine degradation pathway have proven to be closely associated with several human diseases. However, the etiology is not yet fully understood. Profile assay of purine intermediates and uric acid involved in the metabolic pathway can provide additional insight into the nature and severity of related diseases. Purine metabolites are endogenous chemicals with high hydrophilicity, polarity, and similar structures, thus there is a great need for a specific method to quantify them directly in biological fluids with a short running time. Herein, eight purine degradation pathway metabolites, including xanthine, hypoxanthine, guanine, xanthosine, inosine, guanosine, adenosine and uric acid, in human plasma were quantitatively measured using hydrophilic interaction chromatography-tandem high-resolution mass spectrometry (HILIC-HRMS) in a short running time of 10 min. The method was systematically validated for specificity, linearity of the calibration curve, the limit of detection, the limit of quantification, the lower limit of quantification, precision, accuracy, extraction recovery, matrix effect, and stability. The results showed that the method was linear (R2 > 0.99), accurate (the intra- and inter-day recoveries of all analytes ranged from 90.0 % to 110.0 %), and precise (the intra- and inter-day precisions were less than 6.7 % and 8.9 %, respectively) with the lower limits of quantification ranging from 3 to 10,000 ng/mL. The extraction recoveries and matrix effects were repeatable and stable. All the analytes were stable in the autosampler and could be subject to three freeze-thaw cycles. The developed method was ultimately applied to 100 plasma specimens from healthy individuals. The results showed that the concentrations of different purine metabolites varied dramatically in plasma specimens. Diet and body mass index (BMI) were the most significant factors determining purine levels, followed by drinking and sex. Age, smoking and bedtime showed a very weak correlation with purine metabolism. The findings of the present work reveal the characteristics of purine metabolism in human plasma under non-pathological conditions. The results also highlight the factors that can cause changes in purine metabolism, which are useful in developing effective treatment strategies for metabolic disorders of purines, particularly for those caused by lifestyle factors.

Photochemical activity of water-soluble organic compounds in motor vehicle exhaust particulate matter.

Particulate matter from motor vehicle exhaust is a type of important atmospheric particulates, which can absorb sunlight affecting its photochemical behavior. However, the photochemical activity of water-soluble organic compounds (WSOC) in motor vehicle exhaust particulate matter has not been explored. Here, we applied WSOC in particulate matter from motor vehicle exhaust to investigate the photogenerating ability of its reactive oxygen species (ROS) and its effect based on model phenol photodegradation with the comparison between WSOC in diesel particulate matter and in gasoline particulate matter. The WSOC in diesel particulate matter indicates higher abililty to generate ROS. The main active substance produced by WSOC in the presence of light is 3WSOC*, the secondary substance is 1O2, and small amounts of ·OH and O2·- are also produced. Less active material was produced as WSOC photoaging time increases. Furthermore, the WSOC in diesel particulate matter is more sensitive to light exposure compared to WSOC in gasoline particulate matter. The effects of common atmospheric ionic components on model phenol photodegradation were also explored. Whether WSOC of diesel particulate matter or WSOC of gasoline particulate matter, ammonium nitrate, ammonium sulfate, and ferric chloride promote degradation of model phenol, and copper sulfate inhibited model phenol degradation. However, a different trend emerged with the addition of sodium chloride, which promoted the degradation of model phenol in WSOC of diesel particulate matter and inhibited the degradation in WSOC of gasoline particulate matter.

Unraveling the Nanosheet Zeolite-Catalyzed Combustion of Aluminum Nanoparticles-Doped exo-Tetrahydrodicyclopentadiene (JP-10) Energetic Fuel.

Nanosheet MFI zeolites (Zeolite Socony Mobil, five) have grown in popularity in cracking catalysis considering their tunability in porous topologies, acidic sites, and sheet thickness, thus allowing them to selectively adsorb molecules of specific sizes, shapes, and polarities, resulting in improved cracking performance for a specific fuel. Five different MFI zeolites in the form of a mesoporous nanosheet structure with a controlled concentration of acidic sites denoted as NSMFI(y), where y is Si/Al ratio, have been synthesized. The effects of the relative acidity content of these NSMFI(y) samples on the zeolite-catalyzed combustion of aluminum nanoparticles (AlNPs)-aided exo-tetrahydrodicyclopentadiene (JP-10) mixed energetic fuel droplets levitated in an oxygen-argon atmosphere were investigated using time-resolved imaging (optical and thermal infrared) and spectroscopic techniques (UV-vis and FTIR). The addition of 1.0 wt % of NSMFI(y) zeolites to AlNPs-JP-10 fluid fuel results in critically reduced ignition delays (9 ± 2 ms), elevated ignition temperatures (2800 ± 170 K), and prolonged burning times (60 ± 10 ms) with an enhanced combustion efficiency. The NSMFI(y) zeolites, which possess high acidity and significant mesoporosity, play a crucial role in improving the combustion efficiency by effectively catalyzing the chemical activation of JP-10 and prolonging the burning of the igniting droplet. The NSMFI (60) variant with the highest acidic site content achieved a maximum combustion efficiency of 80 ± 6%. A comprehensive catalytic combustion mechanism has been elucidated based on the detected reactive intermediates such as hydroxyl radical (OH) and aluminum monoxide (AlO). These findings will help to critically advance the development of next-generation, sustainable, and innovative mixed nanofluid fuels.

Design of an Electrochemical Cell for Continuous Wave EPR Measurements of Radical Ions.

The combination of continuous wave electron paramagnetic resonance (cw-EPR) with electrochemistry is highly attractive as it allows a clean in-situ generation and the subsequent spectroscopic characterisation of radical ions, which are important intermediates in many photocatalytic cycles as well as light-induced processes occurring in biological systems or optoelectronic devices. Although commercial setups for spectroelectrochemical EPR are available, they are often expensive and tailored to a particular spectroscopic setup.  Here we present a design for a low-cost electrochemical EPR cell that can be used in combination with any commercial cw-EPR instrumentation. The cell design is compared to existing setups and the performance of the cell is evaluated by comparison of EPR spectra obtained by chemical and electrochemical oxidation of a graphene fragment.

Modulating the D-Band Center of Electrocatalysts for Enhanced Water Splitting.

To tackle the global energy scarcity and environmental degradation, developing efficient electrocatalysts is essential for achieving sustainable hydrogen production via water splitting. Modulating the d-band center of transition metal electrocatalysts is an effective approach to regulate the adsorption energy of intermediates, alter reaction pathways, lower the energy barrier of the rate-determining step, and ultimately improve electrocatalytic water splitting performance. In this review, a comprehensive overview of the recent advancements in modulating the d-band center for enhanced electrocatalytic water splitting is offered. Initially, the basics of the d-band theory are discussed. Subsequently, recent modulation strategies that aim to boost electrocatalytic activity, with particular emphasis on the d-band center as a key indicator in water splitting are summarized. Lastly, the importance of regulating electrocatalytic activity through d-band center, along with the challenges and prospects for improving electrocatalytic water splitting performance by fine-tuning the transition metal d-band center, are provided.

Enhancing Oxygen Reduction Reaction of Single-Atom Catalysts by Structure Tuning.

Deciphering the fine structure has always been a crucial approach to unlocking the distinct advantages of high activity, selectivity, and stability in single-atom catalysts (SACs). However, the complex system and unclear catalytic mechanism have obscured the significance of exploring the fine structure. Therefore, we endeavored to develop a three-component strategy to enhance oxygen reduction reaction (ORR), delving deep into the profound implications of the fine structure, focusing on central atoms, coordinating atoms, and environmental atoms. Firstly, the mechanism by which the chemical state and element type of central atoms influence catalytic performance is discussed. Secondly, the significance of coordinating atoms in SACs is analyzed, considering both the number and type. Lastly, the impact of environmental atoms in SACs is reviewed, encompassing existence state and atomic structure. Thorough analysis and summarization of how the fine structure of SACs influences the ORR have the potential to offer valuable insights for the accurate design and construction of SACs.

Promoting effect of Cu as electron transfer medium on NH3-SCO reaction in asymmetric Ag-Ov-Ti-Sm-Cu ring active site.

Selective catalytic oxidation of ammonia (NH3-SCO) has become an effective method to reduce ammonia (NH3) emissions, and is a key part to solve the problem of NH3 pollution. Nevertheless, the optimization of this technology's performance relies heavily on innovation and the development of catalyst design. In this study, a SmCuAgTiOx catalyst with an asymmetric Ag-Ov-Ti-Sm-Cu ring active site was prepared and applied to the NH3-SCO reaction. The low conversion of Cu-based catalysts in NH3 at low temperature and the inherent low N2 selectivity of Ag-based catalysts were solved. The successful creation of the asymmetric ring active site improved the catalyst's reduction performance. Additionally, Cu, acting as an electron transfer medium, plays a crucial role in enhancing electron transfer within the asymmetric ring active site, thus increasing the redox cycle of the catalyst during the reaction. In addition, some lattice oxygen is lost in the catalyst, resulting in the formation of a large number of oxygen vacancies. This process stimulates the adsorption and activation of surface-adsorbed oxygen, facilitating the conversion of NH3 to an amide (NH2) intermediate during the reaction and reducing non-selective oxidation. The N2 selectivity was improved without significantly affecting the performance of Ag-based catalyst. In-situ diffuse reflectance fourier transform infrared spectroscopy (In-situ DRIFTS) analysis reveals that the SmCuAgTiOx catalyst primarily follows an "internal" selective catalytic reduction (iSCR) mechanism in the NH3-SCO reaction, complemented by the imide mechanism. The asymmetric Ag-Ov-Ti-Sm-Cu ring active site developed in this study provides a new perspective for efficiently solving NH3 pollution in the future.

Role of Interfacial Water Structure in the Electroreduction of NO over Cu2O.

The electrochemical nitric oxide reduction reaction (NORR), which utilizes water as the sole hydrogen source, has the potential to facilitate ammonia production while concurrently mitigating pollutants. However, limited research has been dedicated to characterizing the structure of interfacial water due to the challenges associated with probing this intricate system, impeding the development of more efficient catalysts for the NORR process. Herein, the Cu2O microcrystals with distinct exposed facets, including {100}, {110}, and {111}, are employed for the model catalysts to investigate interfacial water structure and intermediate species in the NORR process. The results from shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) indicated that the NORR performance in 0.1 M Na2SO4 (with heavy water as the solvent) was positively correlated to the proportion of hydrated Na+ ion water. In addition, a sequence of intermediates from the NORR, including *NOH, *NH, *NH2, and *NH3, was detected by employing a combination of multiple in situ characterization methods. Furthermore, in conjunction with experimental results and theoretical calculations, we revealed the potential reaction pathway of NORR. This study offers novel insights into the NORR mechanism and valuable guidance for the design of high-performance catalysts for ammonia production.

Putting It All Together: The Roles of Ribosomal Proteins in Nucleolar Stages of 60S Ribosomal Assembly in the Yeast Saccharomyces cerevisiae.

Here we review the functions of ribosomal proteins (RPs) in the nucleolar stages of large ribosomal subunit assembly in the yeast Saccharomyces cerevisiae. We summarize the effects of depleting RPs on pre-rRNA processing and turnover, on the assembly of other RPs, and on the entry and exit of assembly factors (AFs). These results are interpreted in light of recent near-atomic-resolution cryo-EM structures of multiple assembly intermediates. Results are discussed with respect to each neighborhood of RPs and rRNA. We identify several key mechanisms related to RP behavior. Neighborhoods of RPs can assemble in one or more than one step. Entry of RPs can be triggered by molecular switches, in which an AF is replaced by an RP binding to the same site. To drive assembly forward, rRNA structure can be stabilized by RPs, including clamping rRNA structures or forming bridges between rRNA domains.

Dissolved Black Carbon Facilitates the Photodegradation of Microplastics via Molecular Weight-Dependent Generation of Reactive Intermediates.

Photodegradation of microplastics (MPs) induced by sunlight plays a crucial role in determining their transport, fate, and impacts in aquatic environments. Dissolved black carbon (DBC), originating from pyrolyzed carbon, can potentially mediate the photodegradation of MPs owing to its potent photosensitization capacity. This study examined the impact of pyrolyzed wood derived DBC (5 mg C/L) on the photodegradation of polystyrene (PS) MPs in aquatic solutions under UV radiation. It revealed that the photodegradation of PS MPs primarily occurred at the benzene ring rather than the aliphatic segments due to the fast attack of hydroxyl radical (•OH) and singlet oxygen (1O2) on the benzene ring. The photosensitivity of DBC accelerated the degradation of PS MPs, primarily attributed to the increased production of •OH, 1O2, and triplet-excited state DBC (3DBC*). Notably, DBC-mediated photodegradation was related to its molecular weight (MW) and chemical properties. Low MW DBC (<3 kDa) containing more carbonyl groups generated more •OH and 1O2, accelerating the photodegradation of MPs. Nevertheless, higher aromatic phenols in high MW DBC (>30 kDa) scavenged •OH and generated more O2•-, inhibiting the photodegradation of MPs. Overall, this study offered valuable insights into UV-induced photodegradation of MPs and highlighted potential impacts of DBC on the transformation of MPs.

In-Depth Investigation of Role of -BCO2 in the Degradation of Sulfamethazine by Metal-Free Biochar/Persulfate: The Mechanism of Occurrence of Nonradical Process.

The remediation of organic wastewater through advanced oxidation processes (AOPs) based on metal-free biochar/persulfate systems has been extensively researched. In this work, boron-doped alkali lignin biochar (BKC1:3) was utilized to activate peroxymonosulfate (PMS) for the removal of sulfamethazine (SMZ). The porous structure and substantial specific surface area of BKC1:3 facilitated the adsorption and thus degradation of SMZ. The XPS characterization and density functional theory (DFT) calculations demonstrated that -BCO2 was the main active site of BKC1:3, which dominated the occurrence of nonradical pathways. Neither quenching experiments nor EPR characterization revealed the generation of free radical signals. Compared with KC, BKC1:3 possessed more electron-rich regions. The narrow energy gap (ΔEgap = 1.87 eV) of BKC (-BCO2) promoted the electron transfer to the substable complex (BKC@PMS*) on SMZ, driving the electron transfer mechanism. In addition, the adsorption energy of BKC(-BCO2)@PMS was lower (-0.75 eV → -5.12 eV), implying a more spontaneous adsorption process. The O-O (PMS) bond length in BKC(-BCO2)@PMS increased significantly (1.412 Š→ 1.481 Å), which led to the easier decomposition of PMS during adsorption and facilitated the generation of 1O2. More importantly, a combination of Gaussian and LC-MS techniques was hypothesized regarding the attack sites and degradation intermediates of the active species in this system. The synergistic T.E.S.T software and toxicity tests predicted low or even no toxicity of the intermediates. Overall, this study proposed a strategy for the preparation of metal-free biochar, aiming to inspire ideas for the treatment of organic-polluted wastewater through advanced oxidation processes (AOPs).

Visualization of Electrooxidation on Palladium Single Crystal Surfaces via In Situ Raman Spectroscopy.

The electrooxidation of catalyst surfaces is across various electrocatalytic reactions, directly impacting their activity, stability and selectivity. Precisely characterizing the electrooxidation on well-defined surfaces is essential to understanding electrocatalytic reactions comprehensively. Herein, we employed in situ Raman spectroscopy to monitor the electrooxidation process of palladium single crystal. Our findings reveal that the Pd surface's initial electrooxidation process involves forming *OH intermediate and ClO4 - ions facilitate the deprotonation process, leading to the formation of PdOx. Subsequently, under deep electrooxidation potential range, the oxygen atoms within PdOx contribute to creating surface-bound peroxide species, ultimately resulting in oxygen generation. The adsorption strength of *OH and the coverage of ClO4 - can be adjusted by the controllable electronic effect, resulting in different oxidation rates. This study offers valuable insights into elucidating the electrooxidation mechanisms underlying a range of electrocatalytic reactions, thereby contributing to the rational design of catalysts.