Dual Adsorption Research Articles

Asymmetric Polarization Modulation of d-p Hybridization-Enhanced Bidirectional Sulfur Redox Kinetics with Heteronuclear Dual-Atom Catalysts.

Lithium sulfur batteries (LiSBs) represent a highly promising avenue for future energy storage systems, offering high energy density and eco-friendliness. However, the sluggish kinetics of the sulfur redox reaction (SRR) poses a significant challenge to their widespread applications. To tackle this challenge, we have developed an efficient heteronuclear dual-atom catalyst (hetero-DAC) that leverages surface charge polarization to enhance the asymmetric adsorption of sulfur intermediates. This study investigates how asymmetric electronic redistribution of CoFe DACs modulates the d-p orbital hybridization with sulfur intermediates, revealing the mechanisms of moderate adsorption dynamics with enhanced catalytic performance. The dynamic switching between mono and dual adsorption sites, enabled by the heteronuclear polarized configuration, fine-tunes the orbital hybridization, boosting the bidirectional rate-determining steps, that is, the solid-solid conversion of Li2S2 to Li2S and the reverse dissociation of Li2S. Consequently, the thus-designed CoFe DACs cathode delivers impressive rate performance, achieving a high initial specific capacity of 703.9 mA h g-1 at 3 C, with a negligible decay rate of only 0.031% over 1000 cycles, demonstrating sustained long-term cycling stability. This work bridges geometric configurations and electronic structures, elucidating the mechanisms of asymmetric trapping and conversion enabled by hetero-DACs and offering fresh perspectives for catalyst design in LiSBs and beyond.

Electrochemical and quantum chemical investigation on the adsorption behavior of a schiff base and its metal complex for corrosion protection of mild steel in 15 wt% HCl solution

This work evaluates the effectiveness of Schiff base derivatives, namely, 2,2'-((1E,1′E)-((2,2-dimethylpropane-1,3-diyl)bis(azaneylylidene))bis(methaneylylidene))diphenol (DAMD) and (2-((E)-((3-(((E)-2-hydroxybenzylidene)amino)-2,2dimethylpropyl)imino)methyl)phenoxy) zinc (HDMZ), as corrosion inhibitors for mild steel in a 15 % HCl solution. By employing a blend of experimental assessments and theoretical computations, such as electrochemical tests, morphological observations, and theoretical simulations, the study achieved an impressive up to 94.6 % inhibition efficiency. Notably, HDMZ exhibited significant protective properties. The results of PDP showed that both inhibitors act as mixed-type corrosion inhibitors. SEM surface analysis of the uninhibited and inhibited samples revealed the formation of a protective layer of inhibitor molecules on the mild steel surface to mitigate its corrosion. The Langmuir adsorption model verified the occurrence of dual adsorption, while theoretical simulations offered insights into the underlying interaction mechanisms. The identification of Schiff-based inhibitors reveals a pronounced synergistic effect in corrosion inhibition, marking a significant advancement in understanding corrosion control mechanisms. This study illuminates the process of forming covalent bonds between inhibitor molecules and iron atoms, presenting a hopeful path towards the advancement of corrosion inhibitors tailored for industrial use. The parallel adsorption configuration and mutual interactions form a stable structure, reinforcing the organic-metal bonds and enhancing both chemical and physical adhesion to the steel surface. These findings indicate that the synergistic effect of molecular interactions and polar-rich regions offers a promising strategy for designing functional hybrid materials.

Sustainable synthesis and dual adsorption of methyl orange and cadmium ions using biogenic silica-based fibrous silica functionalized with crown ether ionic liquid

In pursuit of sustainable nanomaterial production, this study presents a novel biogenic fibrous silica sphere functionalized with a crown ether ionic liquid for advanced dual-adsorption of methyl orange and Cd(II) from aqueous solution. Sorghum waste serves as the silica source in the adsorbent preparation process, ensuring an eco-friendly approach. The benzo-15-crown-5 ionic liquid is coupled to thiol-functionalized fibrous silica spheres through an efficient thiol-ene click reaction. Under constant conditions (temperature: 298 K, solution volume = 50 mL, adsorbent dosage = 5 mg, pH = 7, shaking speed = 200 rpm), the synthesized material demonstrates maximum adsorption capacities of 507.1 mg g−1 and 306.3 mg g−1 for methyl orange and Cd(II), respectively, according to the Langmuir model. Thermodynamic investigations reveal exothermic adsorption for methyl orange with an enthalpy change of −77.49 KJ mol−1, while endothermic adsorption is observed for Cd(II) with an enthalpy of +24.10 KJ mol−1. The entropy change of adsorption is −0.153 KJ mol−1 K−1 for methyl orange, indicating a more ordered state, and + 0.192 KJ mol−1 K−1 for Cd(II), suggesting increased disorder. The change in Gibbs free energy ranges from −32.66 to −29.60 KJ mol−1 for methyl orange and −32.29 to −35.99 KJ mol−1 for Cd(II), demonstrating that both adsorption processes are spontaneous. These results indicate that the adsorbent has potential as a dual-adsorption material for water remediation applications.

Selective hydrogenolysis of furfuryl alcohol to 1,2-pentanediol over CuMg supported on mesoporous silica: Effect of pore size and shape

Utilizing urea homogeneous precipitation method, Cu and Mg species were successfully supported on SBA-15, KIT-6, and MCM-41 respectively for furfuryl alcohol (FFA) hydrogenolysis to 1,2-pentanediol (1,2-PeD). The catalytic results showed that the yield of 1,2-PeD followed the order of CuMg/SBA-15 > CuMg/KIT-6 > CuMg/MCM-41, especially the maximum of 50.0 % over CuMg/SBA-15 surpassing that of most copper-based catalysts reported. It is found that FFA conversion dramatically increases with the raising of Cu dispersion, attributing to the high exposure of active sites. Meanwhile, the selectivity of 1,2-PeD is strongly depended on the Cu0/Cu+ ratio of catalyst and CuMg/SBA-15 with the highest value of 57.6 % is derived from the largest Cu0/Cu+ ratio. In a word, CuMg/SBA-15 shows the excellent activity along with stability owing to the synergy between large Cu0/Cu+ ratio and good Cu dispersion, providing by two-dimensional hexagonal straight channel arrangement with generous pore diameter. Innovatively, it is put forward that dual adsorption sites of both MgO and Cu species in the CuMg/SBA-15 catalyst promote the FFA ring-opening to yield 1,2-PeD based on the comparison of Cu dispersion, metal-support (M−S) interaction and the adsorption capacity for furan rings with Cu/SBA-15. This study provides a novel approach for catalyst design for this reaction, focusing on optimizing the catalytic performance by fine-tuning structure of the support.

Efficient Electroreduction of Low Nitrate Concentration via Nitrate Self-Enrichment and Active Hydrogen Inducement on the Ce(IV)-Co3O4 Cathode.

Low concentrations of nitrate (NO3-) widely exist in wastewater, post-treated wastewater, and natural environments; its further disposal is a challenge but meaningful for its discharge goals. Electroreduction of NO3- is a promising method that allows to eliminate NO3- and even generate higher-value NH3. However, the massive side reaction of hydrogen evolution has raised great obstacles in the electroreduction of low concentrations of NO3-. Herein, we present an efficient electroreduction method for low or even ultralow concentrations of NO3- via NO3- self-enrichment and active hydrogen (H*) inducement on the Ce(IV)-Co3O4 cathode. The key mechanism is that the strong oxytropism of Ce(IV) in Co3O4 resulted in two changes in structures, including loose nanoporous structures with copious dual adsorption sites of Ce-Co showing strong self-enrichment of NO3- and abundant oxygen vacancies (Ovs) inducing substantial H*. Ultimately, the bifunctional role synergistically promoted the selective conversion of NH3 rather than H2. As a result, Ce(IV)-Co3O4 demonstrated a NO3- self-enrichment with a 4.3-fold up-adsorption, a 7.5-fold enhancement of NH3 Faradic efficiency, and a 93.1% diminution of energy consumption when compared to Co3O4, substantially exceeding other reported electroreduction cathodes for NO3- concentrations lower than 100 mg·L-1. This work provides an effective treatment method for low or even ultralow concentrations of NO3-.

Potassium Ion-Assisted Self-Assembled MXene-K-CNT Composite as High-Quality Sulfur-Loaded Hosts for Lithium-Sulfur Batteries.

We successfully synthesized hybrid MXene-K-CNT composites composed of alkalized two-dimensional (2D) metal carbide and carbon nanotubes (CNTs), which were employed as host materials for lithium-sulfur (Li-S) battery cathodes. The unique three-dimensional (3D) intercalated structure through electrostatic interactions by K+ ions in conjunction with the scaffolding effect provided by CNTs effectively inhibited the self-stacking of MXene nanosheets, resulting in an enhanced specific surface area (SSA) and ion transport capability. Moreover, the addition of CNTs and in situ-grown TiO2 considerably improved the conductivity of the cathode material. K+ ion etching created a more hierarchical porous structure in MXene, which further enhanced the SSA. The 3D framework effectively confined S embedded between nanosheet layers and suppressed volume changes of the cathode composite during charging/discharging processes. This combination of CNTs and alkalized nanosheets functioned as a physical and chemical dual adsorption system for lithium polysulfides (LiPSs). When subjected to a high current at 1.0C, S@MXene-K-0.5CNT with S-loaded of 1.2 mg cm-2 had an initial capacity of 919.6 mAh g-1 and capacity decay rate of merely 0.052% per cycle after 1000 cycles. Moreover, S@MXene-K-0.5CNT maintained good cycling stability even at a high current of up to 5.0C. These impressive results highlight the potential of alkalized 2D MXene nanosheets intercalated with CNTs as highly promising cathode materials for Li-S batteries. The study findings also have prospects for the development of next-generation Li-S batteries with high energy density and prolonged lifespans.

A potential-driven FeMnOx/CNTs film electrode for efficient extraction of WO42- via electrochemical coordination and inner-sphere complexation

A film electrode materials of iron-manganese oxide composite carbon nanotubes (FeMnOx/CNTs) with dual adsorption sites was obtained by a co-precipitation method, which exhibited excellent selectivity of WO42- in an electrochemically switched ion exchange (ESIX) system. The main components of FeMnOx are MnOx and Fe(OH)3. In FeMnOx/CNTs composite film, Fe(OH)3 with abundant hydroxyl functional groups on its surface improved the ion storage capacity, while MnOx served as the main selective separation material to selectively adsorb the WO42-. A scalable ESIX pilot system was also designed to examine the effect of different operating conditions on system performance. The W(Ⅵ) adsorption capacity was as high as 187.76 mg/g and the separation factor of W/Mo was 21.03. Combining experimental characterization and results, it was confirmed that the highly efficient selective extraction of WO42- in neutral solution should be derived from the dual-site (i.e., electrochemical coordination sites on MnOx and electrochemically induced inner-sphere complexation sites on Fe(OH)3) adsorption. Hence, it is believed that such a novel electroactive FeMnOx/CNTs film electrode with dual adsorption sites could be a promising candidate for industrialized tungsten-molybdenum separation by ESIX technology.

Assessment of pyrazole Schiff base's corrosion inhibition effectiveness incorporating oxadiazole moiety on mild steel in 1 M HCl: A holistic theoretical and experimental analysis

Modern industries place a high value on reasonably priced, eco-friendly products that effectively stop metal breakdown. Hence, our goal was to create an ecologically acceptable pyrazole Schiff base (PSB) that would effectively preserve mild steel (MS) during pickling and descaling procedures. We achieved this by integrating oxadiazole, which demonstrated good anti-corrosion capabilities. A complete investigation was conducted using spectroscopic analysis, electrochemical techniques, and gravimetric measurement in 1 M HCl solution. The PSB inhibitor displayed considerable corrosion inhibition on MS. PSB exhibited both cathodic and anodic properties in its dual adsorption pattern, as shown by the electrochemical investigation. Polarization resistance (Rp) values rose with the PSB concentration from 50 to 300 ppm, peaking at 300 ppm with values ranging from 31.01 to 141.21 Ω.cm². At 300 ppm and 298 K, the inhibitor effectiveness reached 90.12 %. Electrochemical testing validated the protection against mixed-type corrosion, while surface examinations (SEM, EDS, CA, AFM) showed that PSB developed a protective antioxidant layer on the MS surface. According to theoretical DFT calculations, PSB adsorbs onto the steel surface in a flat alignment. The remarkable precision of the adsorption process was validated by the high coefficient of determination (R2 = 1) for both Langmuir and other adsorption isotherms. Computational, chemical, and electrochemical analyses all support PSB's superiority as a corrosion inhibitor. The incorporation of aryl and heterocyclic rings improves the PSB structure's molecular stiffness, which facilitates effective adsorption onto the MS surface. This feature creates novel prospects for material protection and corrosion prevention, presenting PSB as a viable and eco-friendly substitute for conventional corrosion inhibitors in industrial applications.

Vat Dye Molecule–Proton Dual Adsorption Catalysis Based on Molybdenum Disulfide for Sustainable Textile Dyeing

Vat Dye Molecule–Proton Dual Adsorption Catalysis Based on Molybdenum Disulfide for Sustainable Textile Dyeing

Properties of multiple Lewis acid sites in alkali metal-exchanged chabazites probed by CO adsorption

Carbon monoxide adsorption on alkali-metal exchanged chabazites (M-CHA, where M = Li, Na, K) was investigated across various Si/Al ratios. The study reveals significant insights into the adsorption behavior, including the persistence of cationic preferences with decreasing Si/Al ratios and the existence of multiple-center interactions involving alkali-metal cations and CO. Results show that for high-silica M-CHA zeolites, CO adsorption is effectively described by single and dual adsorption site models, with cation preferences varying by type. In low-silica zeolites, cation positions are primarily influenced by the aluminum distribution and Coulombic interactions. However, the propensity for single-site cation positions (Si/Al→∞) is preserved to a certain degree. The most noticeable example is the small difference between SIII’ occupancies (cations in 8-membered ring windows) in Na-CHA-2 and K-CHA-2 (0.80 vs. 0.85) that strongly influences the rate of diffusion of CO in the M-CHA-2 samples. While FT-IR spectra of high-silica zeolites can be accurately described using cation site stabilities, interaction energies, and CO stretching frequencies, predicting spectra of low-silica chabazites requires a statistical approach and/or molecular dynamics simulations at the DFT level. The findings demonstrate that the dynamical behavior of adsorbates changes dramatically between different alkali metal-exchanged chabazites, highlighting the complex nature of CO adsorption at multiple Lewis acid sites.

Improving arsenic and cadmium contaminated paddy soil health and rice quality with plant-animal-based modified biochar: A mechanistic study

Arsenic and cadmium (As/Cd) are toxic elements which negatively impact the health and productivity of rice plants by subjecting them to stress. To address these issues, we developed three biochar amendment materials derived from plant-based corn-stover with iron-magnesium modification (FM@CB), char sourced from animal-based eggshells with iron-magnesium modification (FM@EB), and a blend (1:1, w/w) of both (FM@CEB). Batch adsorption experiment revealed that FM@CB exhibited a Langmuir sorption capacity of 77 mg g−1 for As(III) and 107 mg g−1 for Cd(II). In contrast, FM@EB showed values of 63 mg g−1 for As(III) and 115 mg g−1 for Cd(II), both observed in mixed systems. The exothermic dual adsorption mechanisms could include ion exchange, cation-anion bridging, complexation with surface functional groups, and precipitation processes. Pot trials were conducted, and the findings unveiled a substantial enhancement in rice grain yield with a 2% application of FM@CB, FM@EB, and FM@CEB. Specifically, there was a notable increase of 21.9%, 34.9%, and 37.6%, respectively. Simultaneously, the application led to a reduction in grain As levels by 34.4%, 53.2%, and 42.6%, and grain Cd levels by 48.7%, 71.2%, and 59.9%, respectively, in comparison to the no-amendment control condition. Our study observed a transformation in the soil's microbial community, as beneficial bacterial genera such as Anaeromyxobacter, Citrifermentans, and Desulfovibrio emerged to assist in the detoxification of these metal contaminants. Concurrently, the application of these materials led to a reduction in harmful bacterial genera like Pseudomonas, Flavobacterium, and Massilia. In addition, these amendments decreased the bioavailable As/Cd fractions in the soil and promoted the root-iron-plaque, which effectively sequesters these contaminants, rendering rice quality improvement. Ultimately, the use of these amendments, particularly FM@CEB, holds the promise of protecting rice from harmful metal(loid)s contaminants, increasing yields, and revitalizing the soil. The presence of these unique bacterial genera, especially those capable of detoxifying As/Cd, plays a crucial role in ensuring a healthier and more secure environment for all living organisms.

Ferredoxin-Inspired Design of S-Synergized Fe-Fe Dual-Metal Center Catalysts for Enhanced Electrocatalytic Oxygen Reduction Reaction.

Dual-metal center catalysts (DMCs) have shown the ability to enhance the oxygen reduction reaction (ORR) owing to their distinctive structural configurations. However, the precise modulation of electronic structure and the in-depth understanding of synergistic mechanisms between dual metal sites of DMCs at the atomic level remain challenging. Herein, mimicking the ferredoxin, Fe-based DMCs (Fe2N6-S) are strategically designed and fabricated, in which additional Fe and S sites are synchronously installed near the Fe sites and serve as "dual modulators" for coarse- and fine-tuning of the electronic modulation, respectively. The as-prepared Fe2N6-S catalyst exhibits enhanced ORR activity and outstanding Zinc-air (Zn-air) battery performance compared to the conventional single Fe site catalysts. The theoretical and experimental results reveal that introducing the second metal Fe creates a dual adsorption site that alters the O2 adsorption configuration and effectively activates the O─O bond, while the synergistic effect of dual Fe sites results in the downward shift of the d-band center, facilitating the release of OH*. Additionally, local electronic engineering of heteroatom S for Fe sites further facilitates the formation of the rate-determining step OOH*, thus accelerating the reaction kinetics.

Highly selective recovery of palladium using innovative double-layer adsorptive membranes

Palladium (Pd) recovery from secondary resources is urgently needed to meet the rising demands for precious metals for sustainable development and environmental protection. To achieve the goal of simple, efficient, and selective recovery of precious metal Pd, we reported an innovative strategy that utilized a double-layer adsorptive membrane based on polydopamine (PDA) modification and polymethacryloxyethyltrimethyl ammonium chloride (PDMC) grafting. The adsorption results suggested that the adsorptive membrane exhibited an excellent adsorption capacity of 61.5 mg g−1 towards Pd(II) at pH 2.0 and the adsorption capacity remained stable after six cycles. Moreover, the adsorption processes of Pd(II) were fitted to pseudo second-order kinetic models and the Langmuir isotherm models. Density functional theory (DFT) simulation, and FTIR, XPS analysis indicated the adsorption mechanisms were ion exchange from the PDMC layer and chelation and ion exchange from the PDA layer. In the presence of other metal ions (Ni(II), Cu(II), Zn(II), Ca(II), Mg(II), K(I) and Na(I)), the separation factor of adsorptive membrane for Pd(II) was in the range of 50–529. The remarkable selectivity was due to the mechanism of the combination of electrostatic attraction and coordination interaction to Pd(II) while the electrostatic repulsion to other metal cations. Furthermore, membrane filtration results suggested that Pd(II) was effectively adsorbed and rejected and the leakage risk could be reduced by dual adsorption from the double-layer membrane. This study not only offers an innovative strategy to precisely and effectively recover Pd(II) and other platinum group metals, but also provides valuable insights for the future implementation of adsorptive membranes in recycling low-concentration wastewater in an efficient and friendly way.

Nitrate Reduction by NiFe-LDH/CeO2: Understanding the Synergistic Effect between Dual-Metal Sites and Dual Adsorption.

Electrocatalytic nitrate reduction reaction (EC-NITRR) shows a significant advantage for green reuse of the nitrate (NO3-) pollutant. However, the slow diffusion reaction limits the reaction rate in practical EC-NITRR, causing an unsatisfactory ammonia (NH3) yield. In this work, a multifunctional NiFe-LDH/CeO2 with the dual adsorption effect (physisorption and chemisorption) and dual-metal sites (Ce3+ and Fe2+) was fabricated by the electrodeposition method. NiFe-LDH/CeO2 performed an expected ability of enrichment for NO3- through the pseudo-first-order and pseudo-second-order kinetic models, and the polymetallic structure provided abundant sites for effective reaction of NO3-. At-0.6 V vs RHE, the ammonia (NH3) yield of NiFe-LDH/CeO2 reached 335.3 μg h-1 cm-2 and the selectivity of NH3 was 24.2 times that of NO2-. The nitrogen source of NH3 was confirmed by 15NO3- isotopic labeling. Therefore, this work achieved the recycling of the NO3- pollutant by synergy of enrichment and catalysis, providing an alternative approach for the recovery of NO3- from wastewater.

Deposited PtGe Clusters as Active and Durable Catalysts for CO Oxidation**

AbstractControl of CO emissions raises serious environmental concerns in the current chemical industry, as well as in nascent technologies based on hydrogen such as electrolyzers and fuel cells. As for now, Pt remains one of the state‐of‐the‐art catalysts for the CO oxidation reaction, but unfortunately, it suffers from CO self‐poisoning. Recently, Pt−Ge alloys were proposed to be an excellent alternative to reduce CO poisoning. This work investigates the impact of Ge content on the CO oxidation kinetics of Pt4Gen subnanoclusters supported on MgO. A Ge concentration dependence of the reaction kinetics is found due to a strong synergy between Pt and Ge. Pt−Ge nanoalloys act as a bifunctional catalyst by displaying dual adsorption sites; i. e., CO is adsorbed on Pt whereas oxygen binds to Ge, forming an alternative oxygen source GeOx. Besides, Ge alloying modifies the electronic structure of Pt (ligand effects) and reduces the affinity to CO. In this way, the competition between CO and O2 adsorption and the overbinding of CO is alleviated, achieving a CO poisoning‐free kinetic regime. Our calculations suggest that Pt4Ge3 is the optimal catalyst, evidencing that alloying composition is a parameter of extreme importance in nanocatalyst design. The work relies on global optimization search techniques to determine the accessibility of multiple structures at different conditions, mechanistic studies and microkinetic modeling.

Orchestrating dual adsorption sites and unravelling Ce-Mn interaction and reaction mechanisms for efficient NH3-SCR

Mechanism insight is suggested to be one of the most challenging issues in selective catalytic reduction of NO with NH3 (NH3-SCR), and the development of efficient NH3-SCR catalysts for industrial application needs a deep understanding of the catalytically active sites, reaction pathways and rate-determining steps. Herein, we study the NH3-SCR reaction mechanism on CeMn oxide catalyst. Mn3+ ions enter the CeO2 lattice to generate a Mn-O-Ce structure with a strong interaction, and Ce can synergize Mn species to orchestrate co-adsorption and accelerate the reaction rate. Theoretical studies verify that Ce and Mn sites act as double adsorption sites for NH3 and NOx, respectively. The proposed two reaction pathways including NH3 with NO and NH3 with NO2 may occur simultaneously owing to the same rate-determining step and the similar energy barriers. More interesting, the simulation results suggest that oxygen vacancies can automatically generate and supplement during the NH3-SCR reaction. This present work highlights the importance of elaborately modulating the double adsorption sites for NH3 and NOx and proposes the possible reaction mechanisms.

Surface interaction and inhibition mechanisms of hydrazide derivatives on N80 steel in acidizing media: A comprehensive analysis through experimental and theoretical methods

This study evaluates hydrazide derivatives, PEH and PAH, as corrosion inhibitors for N80 steel in acidic conditions. Utilizing a blend of experimental tests and theoretical calculations, including EIS, PDP, SEM, DFTB, and MD simulations, up to 96% inhibition efficiency was attained. Specifically, the PAH compound displayed notable protection. The Langmuir adsorption model confirmed dual adsorption, and theoretical simulations revealed interaction mechanisms. The research provides valuable insights into the formation of covalent bonds between inhibitor molecules and iron atoms, and offers a promising path for the development of advanced corrosion inhibitors suitable for industrial applications.

Simple synthesis of Cu/Cu2O/CuO composites with dual adsorption capacity for conductometric NO2 detection

Starting from improving the sensing performance of sensing materials to NO2, it is still a challenge to synthesize a material that can simultaneously enhance the adsorption capacity of NO2 and the surface adsorbed oxygen content. In this paper, nano-sized octahedral HKUST-1 precursor was prepared by one-step hydrothermal method. After subsequent sintering treatment at different temperatures, a series of CuO-based composites with oxygen vacancies and pores were obtained. Among them, Cu/Cu2O/CuO composite shows the best response for 1 ppm NO2 at 50 °C (S =14.4), and excellent selectivity, moisture resistance and reproducibility. The minimum detection limit is as low as 50 ppb. In addition, XPS, PL, NO2-TPD analyses and DFT calculations were used to study the reasons in detail for the excellent NO2 gas sensing performance of Cu/Cu2O/CuO. The presence of Cu in the composite improves the ability of material to adsorb NO2, while the presence of Cu2O and oxygen vacancies make the material have more surface adsorbed oxygen. The combined effect of the two makes the material have good NO2 gas sensing performance. The synthesis of this composite material provides new ideas for improving the detection ability of toxic and harmful gases.

Supercritical methane adsorption in coal and implications for the occurrence of deep coalbed methane based on dual adsorption modes

Supercritical methane adsorption in coal and implications for the occurrence of deep coalbed methane based on dual adsorption modes

Unveiling the Remarkable Stability and Catalytic Activity of a 6-Electron Superatomic Ag30 Nanocluster for CO2 Electroreduction.

Nanocluster catalysts face a significant challenge in striking the right balance between stability and catalytic activity. Here, we present a thiacalix[4]arene-protected 6-electron [Ag30(TC4A)4(iPrS)8] nanocluster that demonstrates both high stability and catalytic activity. The Ag30 nanocluster features a metallic core, Ag104+, consisting of two Ag3 triangles and one Ag4 square, shielded by four {Ag5@(TC4A)4} staple motifs. Based on DFT calculations, the Ag104+ metallic kernel can be viewed as a trimer comprising 2-electron superatomic units, exhibiting a valence electron structure similar to that of the Be3 molecule. Notably, this is the first crystallographic evidence of the trimerization of 2-electron superatomic units. Ag30 can reduce CO2 into CO with a Faraday efficiency of 93.4% at -0.9 V versus RHE along with excellent long-term stability. Its catalytic activity is far superior to that of the chain-like AgI polymer ∞1{[H2Ag5(TC4A)(iPrS)3]} (∞1Agn), with the composition similar to Ag30. DFT calculations elucidated the catalytic mechanism to clarify the contrasting catalytic performances of the Ag30 and ∞1Agn polymers and disclosed that the intrinsically higher activity of Ag30 may be due to the greater stability of the dual adsorption mode of the *COOH intermediate on the metallic core.