Conversion Of Intermediates Research Articles

Stereoselective synthesis of geminal bromofluoroalkenes by kinetically controlled selective conversion of oxaphosphetane intermediates.

Geminal bromofluoroalkenes are an important subclass of versatile organic interhalide, which can serve as useful synthetic precursors to monofluoroalkenes that are valuable amide group isosteres. Nonetheless, despite the vast advancement of olefination methodologies, the broadly applicable stereoselective synthesis remained elusive for geminal bromofluoroalkenes before our work. In particular, the seemingly straightforward Wittig-type approach with interhalogenated phosphorus ylide has been unsuccessful because of the difficulty in the diastereoselective oxaphosphetane formation. Here, we describe a conceptually distinctive strategy, by which the stereoselectivity is gained via the selective decomposition of the oxaphosphetane intermediates. The suitably identified phosphorus(III) reagent and reaction medium enabled efficient kinetic differentiation, which was supported by nuclear magnetic resonance analysis and density functional theory calculation. Through our method, the highly diastereoselective synthesis of geminal E-bromofluoroalkenes was accomplished in one step. Furthermore, the generality was demonstrated by accommodating a wide range of readily available carbonyl compounds, including ketones and pharmaceutical substrates.

Synergistic Interaction of Strongly Polar Zinc Selenide and Highly Conductive Carbon Nanoframeworks Accelerates Redox Kinetics of Polysulfides.

Lithium-sulfur batteries (LSBs) have become strong competitors in secondary battery systems because of their superior theoretical capacity and energy density. However, due to the serious shuttle effect of soluble long-chain lithium polysulfides (LiPSs) and the slow solid-solid reaction kinetics, LSBs face some specific challenges, such as a short cycle life and low rate performance. The introduction of selenide/carbon composites derived from zeolite imidazolate frameworks (ZIFs) into separator coatings is a direct and effective solution to the aforementioned problems. Here, a zinc selenide/carbon catalyst material (ZnSe@C) was constructed and employed to modify commercial polypropylene (PP) separators to accelerate the conversion of intermediates. The highly polar ZnSe effectively fixes the active material on the cathode side by transferring electrons between elements with LiPSs and improves the utilization rate of sulfur. Concurrently, the highly conductive carbon nanoskeleton generated following the pyrolysis of ZIF-8 ensures the rapid transfer of charges during the catalytic reaction. The prepared ZnSe@C has a large specific surface area (250.07 m2 g-1) and mesoporous ratio (78.03%), which not only enhances adsorption and catalysis but also promotes the penetration of the electrolyte and the transport of Li+. Based on this, ZnSe@C/PP separator cells exhibit a low average capacity decay rate of 0.051% per cycle after 500 cycles at 1 C.

Enhancing burning rate of ammonium nitrate by ammonia borane: Mechanism from reactive molecular dynamics simulation.

The development of ammonium nitrate (AN)/ammonia borane (AB) as a green propellant is crucial for their applicability in different engines. This study investigates the release patterns of small products, particularly nitrogen-containing molecules, during the initial pyrolysis of AN/AB at low and high pressures using ReaxFF MD simulations. Compared with pure AN, the addition of AB gives the hybrid system enhanced reactivity, leading to faster decomposition and higher energy release. The results show that the consumption of AN in the S13 system (AB with a mass ratio of 12.6 %) is accelerated at 1.47 MPa. NO2 and NO are produced through HNO3 and NO3. At 6.89 MPa, AN exhibits the fastest decomposition rate in the S15 system. The high pressure enhances more reactions of NO with free radicals such as NH and accelerates the release of N2. As the percentage content of AB increases to 15.3%, more H2O while more NO2 is generated. The effect of AB on the generation of radicals such as H2 and H, is analyzed. AB not only promotes the initial pyrolysis of AN but also accelerates the conversion of intermediates.

Isocyanide Substituent Influences Reductive Elimination versus Migratory Insertion in Reaction with an [Fe2(μ-H)2]2+ Complex.

Iron hydrides are proposed reactive intermediates for N2 and CO conversion in industrial and biological processes. Here, we report a reactivity study of a low-coordinate di(μ-hydrido)diiron(II) complex, Fe2(μ-H)2L, where L2- is a bis(β-diketiminate) cyclophane, with isocyanides, which have electronic structures related to N2 and CO. The reaction outcome is influenced by the isocyanide substituent, with 2,6-xylyl isocyanide leading to H2 loss, to form a bis(μ-1,1-isocyanide)diiron(I) complex, whereas all of the other tested isocyanides insert into the Fe-H bond to give (μ-1,2-iminoformyl) complexes. Steric bulk of the isocyanide substituent determines the extent of insertion (i.e., into one or both Fe-H-Fe units) with tert-butyl isocyanide reacting to yield the mono-(μ-1,2-iminoformyl)diiron(II) complex, exclusively, and isopropyl- and methyl isocyanides affording the bis(μ-1,2-iminoformyl)diiron(II) products. Treatment of Fe2(μ-1,2-CHNtBu)(μ-H)L with 2,6-xylyl isocyanide (or XylNC) yields Fe2(μ-XylNC)2L and tert-butylaldimine as one of the organic products.

The Dual Role of Natural Organic Matter in the Degradation of Organic Pollutants by Persulfate-Based Advanced Oxidation Processes: A Mini-Review

Persulfate-based advanced oxidation processes (PS-AOPs) are widely used to degrade significant amounts of organic pollutants (OPs) in water and soil matrices. The effectiveness of these processes is influenced by the presence of natural organic matter (NOM), which is ubiquitous in the environment. However, the mechanisms by which NOM affects the degradation of OPs in PS-AOPs remain poorly documented. This review systematically summarizes the dual effects of NOM in PS-AOPs, including inhibitory and promotional effects. It encompasses the entire process, detailing the interaction between PS and its activators, the fate of reactive oxygen species (ROS), and the transformation of OPs within PS-AOPs. Specifically, the inhibiting mechanisms include the prevention of PS activation, suppression of ROS fate, and conversion of intermediates to their parent compounds. In contrast, the promoting effects involve the enhancement of catalytic effectiveness, contributions to ROS generation, and improved interactions between NOM and OPs. Finally, further studies are required to elucidate the reaction mechanisms of NOM in PS-AOPs and explore the practical applications of PS-AOPs using actual NOM rather than model compounds.

Constructing dual-channel carrier transport in AgBr/BiOBr/Ag3PO4 heterojunctions for enhanced photocatalytic NO removal

Efficient and stable photocatalysts are indispensable for effectively reducing nitrogen oxide (NOx) emissions. This study presents a facile method for synthesizing AgBr/BiOBr/Ag3PO4 composites and investigates their application in photocatalytic NO removal. The optimized composite exhibited notable performance, achieving 54.95 % removal of NO (approximately 568 ppb reduced to 256 ppb) under visible light irradiation, which is about 1.6 and 2.0 times higher than single Ag3PO4 (34.95 %) and BiOBr (28.01 %), respectively. Comprehensive physicochemical characterization highlighted enhancements in light absorption and the generation of reactive radicals within the AgBr/BiOBr/Ag3PO4 composite. The favorable electronic structure, characterized by well-aligned redox band positions, facilitated efficient dual carrier transport routes, thereby promoting the separation of photo-generated charge carriers. Additionally, in-situ DRIFTS analysis revealed that the composite facilitated the conversion of intermediates into nitrates during the NO purification process. This work contributes valuable insights into designing and preparing of ternary heterojunction photocatalysts with dual carrier transport channels, advancing strategies for achieving superior photocatalytic performance.

New Insights for High-Throughput CO2 Hydrogenation to High-Quality Fuel.

In the case of CO2 thermal-catalytic hydrogenation, highly selective olefin generation and subsequent olefin secondary reactions to fuel hydrocarbons in an ultra-short residence time is a huge challenge, especially under industrially feasible conditions. Here, we report a pioneering synthetic process that achieves selective production of high-volume commercial gasoline with the assistance of fast response mechanism. In situ experiments and DFT calculations demonstrate that the designed NaFeGaZr presents exceptional carbiding prowess, and swiftly forms carbides even at extremely brief gas residence times, facilitating olefin production. The created successive hollow zeolite HZSM-5 further reinforces aromatization of olefin diffused from NaFeGaZr via optimized mass transfer in the hollow channel of zeolite. Benefiting from its rapid response mechanism within the multifunctional catalytic system, this catalyst effectively prevents the excessive hydrogenation of intermediates and controls the swift conversion of intermediates into aromatics, even in high-throughput settings. This enables a rapid one-step synthesis of high-quality gasoline-range hydrocarbons without any post-treatment, with high commercial product compatibility and space-time yield up to 0.9 kggasoline ⋅ kgcat -1 ⋅ h-1. These findings from the current work can provide a shed for the preparation of efficient catalysts and in-depth understanding of C1 catalysis in industrial level.

Facilitating CO2 methanation over oxygen vacancy-rich Ni/CeO2: Insights into the synergistic effect between oxygen vacancy and metal-support interaction

The catalytic hydrogenation of CO2 into CH4 is a versatile strategy to realize green development goals, whereas developing low-cost and high-performance catalysts remains a significant challenge. Herein, highly active Ni0/NiO supported on oxygen vacancy-rich CeO2 (Ni/CeO2-Ov-R) was designed, which exhibited ∼76 % CO2 conversion coupled with 100 % CH4 selectivity at a low temperature of 250 °C. In addition, such satisfactory reaction performance could be maintained over 80 h at 300 °C. The density functional theory (DFT) calculations elaborated that oxygen vacancies were more easily formed on the CeO2 (1 1 0) plane of Ni/CeO2-Ov-R. Compared with Ni/CeO2-Ov-medium (Ni/CeO2-Ov-M) and Ni/CeO2-Ov-poor (Ni/CeO2-Ov-P) with relatively insufficient oxygen vacancy, the copious oxygen vacancies of Ni/CeO2-Ov-rich was apt to enhance the interaction between the CeO2 support and Ni species as confirmed through H2-TPR and XPS. Noteworthily, the abundant medium-strength basic sites and surface oxygen vacancy of Ni/CeO2-Ov-rich were more conducive to upshifting the activation adsorption of CO2 and accelerate the conversion of intermediates. Besides, the oxygen vacancies also make a great contribution to the enhancement of the potential for hydrogen dissociation because of the enhanced number of exposed Ni0. In situ DRIFTS displayed that the CO and formate (HCOO–) routes co-existed on Ni/CeO2 catalysts, revealing that oxygen vacancy and exposed Ni0 boosted the CO2 and H2 activation. This work proposes a deeper insight into the precise regulation of the oxygen vacancy of Ni/CeO2 catalyst and opens a path for exploiting CO2 methanation catalysts with a potential application.

Insights into lignin bioconversion: lignin-derived compounds treatment of a novel marine fungus K-2.

The potential for the efficient conversion of lignocellulosic biomass has been extensively explored to produce a wide range of bioproducts. Many approaches have been sought for the deep conversion of lignin to generate products that are toxin-free and beneficial for processing into high-value-added components. This study reported a fungus isolated from the deep sea with strong synthesis of multiple lignocellulases, conversion of lignin and guaiacol (0.1%) by 71.6% and 86.1% within 9 days at 30 °C respectively, and outstanding environmental adaptability (20-50 °C and pH 3-8). Metabolic pathway profiling showed that this fungus utilized lignin to rapidly activate multiple ring-opening reactions including the 2,3- and 3,4-cleavage pathways, with the 2,3-cleavage pathway predominating after 5 days. Conversion of metabolic intermediates confirmed the superb potential of this strain for lignin treatment. Meanwhile, its shikimic acid pathway was metabolically active under lignin. This further expands the potential to produce valuable bioproducts during lignin treatment, especially under ambient conditions, which can significantly enhance high-value precursor compound production. © 2024 Society of Chemical Industry.

Cobalt-doped Ni-based catalysts for low-temperature CO2 methanation

The study of the process and mechanism of CO2 activation and the development of low-temperature, high-activity and selective catalysts for CO2 methanation are current research hotspots. In this paper, a series of Ni/Al2O3 catalysts with different Co contents were prepared by using layered double hydroxides (LDHs) as precursors for low-temperature CO2 methanation, and the incorporation of Co promoted the electron transfer from Ni to Co, which facilitated the adsorption and activation of CO2 and H2. The spent catalyst still maintained the layered structure with no significant change in the metal particle size, indicating that the addition of Co significantly improved the long-term stability of the catalysts. The CO2 conversion was 55.5 % and STYCH4 was 148.0 mmol·gcat−1 h−1 at 200 °C, 2.0 MPa and 1000 h−1. The in situ DRIFTS experiments showed that the addition of Co accelerated the conversion of the reaction intermediates and promoted the generation of methane.

Understanding the impact of pre-digestion thermal hydrolysis process on PFAS in anaerobically digested biosolids

Per- and poly-fluoroalkyl substances (PFAS) present in biosolids are influenced by their source, treatment processes, and the dynamics of water resource recovery facilities (WRRF). Understanding these effects is vital for informed decisions in treatment process selection, however, comprehensive studies are sparse. This study examined the impact of anaerobic digestion (AD) and the addition of a thermal hydrolysis process (THP) before AD on PFAS in the solids stream at a WRRF. Targeted analysis of 58 PFAS (linear and branched) and suspect screening of the solid stream before and after AD as well as THP, with the total PFAS (ΣPFAS) concentrations ranging between 244 and 566 μg/kgdw. Precursor and intermediate PFAS, mainly di-substituted polyfluoroalkyl phosphate esters (diPAPs) followed by fluorotelomer carboxylic acids (FTCAs), were the dominant contributors (62–96 mol % ΣPFAS) in all 5 sample types. AD impacts were observed both before and after deploying THP altering the relative contribution of different PFAS classes through biotransformation, with an increase in PFCAs and a decrease in diPAPs. However, we observed that THP reduced the % of precursor conversion as well as conversion of the FTCA intermediates in the AD process as evidenced by a substantial increase in FTCAs post-THP + AD and lower PFCA generation compared to AD only. Total PFAS organofluorine (∑FPFAS) decreased by 28% pre- and post-AD, which on total fluorine (TF) showed a larger reduction to 43%. Fluoride was <3% of the TF in all cases, thus, the greater reduction in TF vs ∑FPFAS could be volatile losses of PFAS and other non-PFAS F-containing molecules. After THP installation, a 32% decrease in (∑FPFAS) was observed in the combined THP-AD system whereas adjusted total organofluorine increased by ∼43%. Overall, achieving higher solids handling capacity and energy neutrality with the THP addition did not lead to a significant difference in quantifiable PFAS concentrations compared to AD-only.

Passivation of the positive electrode during the discharge of Li-O2 and O2-assisted Li-CO2 batteries: A comparative study

The effect of passivation of the positive electrode by solid products under discharge is assessed for the first time as one of the factors determining the discharge characteristics of Li-O2 (LOB) and oxygen-assisted Li-CO2 (LCOB) batteries. In order to estimate the passivation, the electrode surface coverage θ by the reaction product (Li2O2 or Li2CO3) is determined on the basis of a decrease in the double-layer capacitance value in the course of the discharge. It is shown that for a given amount of electricity, the electrode surface coverage by Li2CO3 in LCOB is 1.5–2 times that of the coverage by Li2O2 under discharge in LOB. Furthermore, for each of the batteries, achievement of the maximum discharge capacity does not result in the full electrode surface blocking by the discharge products. LCOB manifests higher discharge characteristics than LOB under the kinetic reaction control (in the 100–500 mA g−1 current density range), owing to the accelerated conversion of intermediates and slower solid reaction product deposition on a larger electrode surface area. As the current density increases from 500 to 2000 mA g−1, the discharge capacity of LOB and LCOB decreases, which is mainly due to the effect of diffusion limitations. Moreover, while in the case of LOB the parameter θ decreases, in the case of LCOB it is practically independent of the current density in the studied range. The latter effect may be due to increased passivating properties of Li2CO3 deposits formed under high current density. The results of the work allow considering θ as a new criterion for estimation of the discharge depth and for predicting the characteristics of LCOB and LOB.

Defluorinative Haloalkylation of Unactivated Alkenes Enabled by Dual Photoredox and Copper Catalysis.

A three-component defluorinative haloalkylation of alkenes with trifluoromethyl compounds and TBAX (X = Cl, Br) via dual photoredox/copper catalysis is reported. The mild conditions are compatible with a wide array of activated trifluoromethyl aromatics bearing diverse substituents, and various nonactivated terminal and internal alkenes, enabling straightforward access to synthetically valuable γ-gem-difluoroalkyl halides with high efficiency. Mechanistic studies indicate that the [Cu] complexes not only serve as XAT catalysts but also facilitate the SET reduction of trifluoromethyl groups by photocatalysts. Additionally, the resulting alkyl halide products can serve as versatile conversion intermediates for the synthesis of a diverse range of γ-gem-difluoroalkyl compounds.

In-Situ investigation of the catalytic hydrogenation reaction of 4-nitrothiophenol by using single Pt@Au nanowires as a new platform

Investigating the kinetics and mechanisms of catalytic hydrogenation reaction is important for fundamental research and chemical engineering, especially at single nanowire/nanoparticle level. In this work, we constructed a dual-functional single Pt@Au nanowire (Pt@Au NW) reaction platform, which was used for in-situ monitoring the p-nitrothiophenol (4-NTP) catalytic reduction process by using surface-enhanced Raman scattering (SERS) and UV–vis spectroscopy. The conversion of reactants and intermediates as well as the product generation during the reaction process were analyzed carefully, and the influencing factors of temperature and light were also discussed. Moreover, the density functional theory (DFT) was used to further investigate the effect of the single Pt@Au NW on catalytic hydrogenation reaction of 4-NTP. The results show that the single Pt@Au NW can be a good platform for in-situ monitoring catalytic hydrogenation reaction of 4-NTP with excellent catalytic activity, high stability, and good reproducibility, and clarified that trans-dimercaptoazobenzene (trans-DMAB) intermediates were produced that are further converted to the p-aminothiophenol (4-ATP). The work will not only give researchers new insights into the combination of the single nanowire/nanoparticle with spectroscopic techniques, but may also inspire further in-depth studies of multifunctional catalysts for catalytic hydrogenation reaction at single entity level.

Enhanced electrocatalytic nitrate reduction via carbon material integration between Cu and Ni-foam: Mechanisms and performance analysis

This study investigates the electrocatalytic reduction of nitrates using three novel electrodes: Cu@CNFs/NF, Cu@CNTs/NF, and Cu@CB/NF, synthesized via an impregnation-calcination-electrodeposition technique. The emphasis is on the role of different carbon materials, which serve as the base or matrix for Cu, and their influence on nitrate reduction and nitrogen selectivity. Experimental results indicated that all three-electrode variants outperformed the conventional Cu/NF electrode in nitrate reduction and nitrogen selectivity. Among these, the Cu@CNFs/NF electrode emerged as the standout performer, achieving an impressive nitrate reduction rate of up to 98 % and a nitrogen selectivity of 51 % under the optimized experimental conditions (pH 7, nitrate concentration of 100 mg∙L-1 as NO3–-N, a current density of 8 mA cm−2, a sodium sulfate concentration of 0.5 g∙L-1, 120 min, anode: Ti/RuO2-IrO2). Stability tests confirmed that the Cu@CNFs/NF electrode maintained over 97 % nitrate removal efficiency across ten cycles, highlighting its robustness and potential for practical water treatment applications. A significant enhancement in nitrogen selectivity of Cu@CNFs/NF to 96 % was observed when using 0.75 g∙L-1 NaCl as the electrolyte during an extended electrolysis period of 180 min, underscoring its potential to optimize catalytic efficiency. Characterization data from SEM, XRD, and other analyses substantiate that the incorporation of carbon materials augments the active sites of copper; Nitrogen adsorption–desorption experiments further illustrate that the integration of carbon materials leads to an increase in mesoporous volume. This increase promotes adsorptive interactions, enhances the conversion of intermediates, and contributes to the improvement of nitrate reduction and nitrogen selectivity. These results highlight the potential of tailored carbon material integration for enhancing the electrocatalytic performance of electrodes in practical water treatment applications.

Upcycling of medical protective clothing for H2 production through catalytic steam reforming over Ni-impregnated catalysts

Disposing medical protective clothing (MPC) presents a significant challenge due to the potential risk of virus contamination. Catalytic steam reforming using Ni-impregnated catalysts was proposed to upcycle MPC for H2-rich gas production. Parametric studies validated that an optimal steam rate of 42 mL/h and a catalytic reforming temperature of 800 ℃ were ideal for H2-rich gas production. 10 wt% Ni impregnated on diverse supports (HY, ZSM-5, MCM-41, γ-Al2O3, MgO, CaO, and activated carbon) were prepared for steam reforming of MPC to assess the impact of support type on H2 production. Of these Ni-impregnated catalysts, Ni/CaO was found to present the highest gas yield (141.4 mmol/g) with a high H2 proportion of 65.2 vol%, due to its superior catalytic cracking and reforming ability of Ni/CaO, favoring the conversion of MPC intermediates into H2-rich gas. To evaluate the recyclability and reforming activity, the optimized Ni/CaO with and without catalyst regeneration was evaluated throughout the successive tests. It was found that Ni/CaO regenerated throughout the successive tests could more effectively mitigate the decreasing tendency of gas yields, favor H2 production, and reduce tar formation than the catalyst without regeneration. That was due to the removal of carbon deposition by catalyst regeneration, thereby mitigating the catalyst deactivation. In contrast, Ni/CaO without the catalyst regeneration was more responsible for the CO2 reduction, accompanying with a more significant decrease of ƞ (4.8 – 3.5 g CO2 /g H2). Overall, this study demonstrated the feasibility of valorizing medical plastic waste into H2-rich gas using effective Ni-based catalysts.

Endogenous base damage as a driver of genomic instability in homologous recombination-deficient cancers

Homologous recombination (HR) is a high-fidelity DNA double-strand break (DSB) repair pathway. Both familial and somatic loss of function mutation(s) in various HR genes predispose to a variety of cancer types, underscoring the importance of error-free repair of DSBs in human physiology. While environmental sources of DSBs have been known, more recent studies have begun to uncover the role of endogenous base damage in leading to these breaks. Base damage repair intermediates often consist of single-strand breaks, which if left unrepaired, can lead to DSBs as the replication fork encounters these lesions. This review summarizes various sources of endogenous base damage and how these lesions are repaired. We highlight how conversion of base repair intermediates, particularly those with 5′or 3′ blocked ends, to DSBs can be a predominant source of genomic instability in HR-deficient cancers. We also discuss how endogenous base damage and ensuing DSBs can be exploited to enhance the efficacy of Poly (ADP-ribose) polymerase inhibitors (PARPi), that are widely used in the clinics for the regimen of HR-deficient cancers.

Photocatalytic Cracking of non-Biodegradable Plastics to Chemicals and Fuels.

Plastic pollution is worsening the living conditions on Earth, primarily due to the toxicity and stability of non-biodegradable plastics (NBPs). Photocatalytic cracking of NBPs is emerging as a promising way to cleave inert C-C bonds and abstract the carbon atoms from these wastes into valuable chemicals and fuels. However, controlling these processes is a huge challenge, ascribed to the complicated reactions of various NBPs. Herein, we summarize recent advances in the CO2 and carbon-radical-mediated photocatalytic cracking of NBPs, with an emphasis on the pivotal intermediates. The CO2-mediated cracking proceeded with indiscriminate C-H/C-C bond cleavage of NBPs and tandem photoreduction of CO2, while carbon-radical-mediated cracking was realized by the prior activation of C-H bonds for selective C-C bond cleavage of NBPs. Catalytic generation and conversion of different intermediates greatly depend on the kinds of active species and the structure of photocatalysts under irradiation. Meanwhile, the fate of a specific intermediate is compared with small molecule activation to reveal the key problems in the cracking of NBPs. Finally, the challenges and potential directions are discussed to improve the overall efficiency in the photocatalytic cracking of NBPs.

Photocatalytic Cracking of non‐Biodegradable Plastics to Chemicals and Fuels

AbstractPlastic pollution is worsening the living conditions on Earth, primarily due to the toxicity and stability of non‐biodegradable plastics (NBPs). Photocatalytic cracking of NBPs is emerging as a promising way to cleave inert C−C bonds and abstract the carbon atoms from these wastes into valuable chemicals and fuels. However, controlling these processes is a huge challenge, ascribed to the complicated reactions of various NBPs. Herein, we summarize recent advances in the CO2 and carbon‐radical‐mediated photocatalytic cracking of NBPs, with an emphasis on the pivotal intermediates. The CO2‐mediated cracking proceeded with indiscriminate C−H/C−C bond cleavage of NBPs and tandem photoreduction of CO2, while carbon‐radical‐mediated cracking was realized by the prior activation of C−H bonds for selective C−C bond cleavage of NBPs. Catalytic generation and conversion of different intermediates greatly depend on the kinds of active species and the structure of photocatalysts under irradiation. Meanwhile, the fate of a specific intermediate is compared with small molecule activation to reveal the key problems in the cracking of NBPs. Finally, the challenges and potential directions are discussed to improve the overall efficiency in the photocatalytic cracking of NBPs.

A Highly Reversible Sn‐Air Battery Possessing the Ultra‐Low Charging Potential with the Assistance of Light

AbstractAqueous Sn‐air batteries are attracting a great deal of interest in recent years due to the ultra‐high safety, low cost, dendrite‐free and highly reversible Sn anode. However, the slurry oxygen reduction/evolution reaction (ORR/OER) kinetics on the air cathodes seriously affect the Sn‐air battery performances. Although various advanced catalysts have been developed, the charge overpotentials (~1000 mV) of these Sn‐air batteries are still not satisfactory. Herein, iron oxide (Fe2O3) modified titanium dioxide (TiO2) nanorods with heterogeneous structure are firstly synthesized on Ti mesh (Fe2O3@TiO2/Ti), and the obtained Fe2O3@TiO2/Ti films are further applied as catalytic electrodes for Sn‐air batteries. The core–shell heterogeneous structure of Fe2O3@TiO2/Ti can effectively facilitate the conversion of electrochemical intermediates and separation of photo‐excited electrons and holes to activate oxygen‐related reaction processes. Density functional theory (DFT) and experimental results also confirm that Fe2O3@TiO2/Ti can not only act as the electrocatalysts to improve ORR/OER properties, but also exhibit the superior photo‐catalytic activity to promote charging kinetics. Hence, the Fe2O3@TiO2/Ti‐based Sn‐air batteries show ultra‐low overpotential of ~40 mV, excellent rate capability and good cycling stability under light irradiation. This work will shed light on rational photo‐assisted catalytic cathode design for new‐type metal‐air batteries.