Electronic Metal-support Interactions Research Articles

Dewetted Nanoparticles – a Platform to Study Nanoscale Effects in Electrocatalysis

To obtain interpretable electrochemical responses and define design criteria for electrocatalysts with enhanced performance, it is crucial to minimize the chemical and material complexity of electrodes [1]. Wet chemical methods are often applied in research to produce high surface area electrocatalysts, typically in the form of inks and coatings, including additives, binders, ionomers, etc., hence featuring complex, often unknown, structure, morphology, and chemical composition. This complexity might also lead to undesired mass transfer limitations and make it difficult to assess intrinsic catalytic properties of electrocatalysts.This contribution is on designing and nanostructuring binder- and ionomer-free electrodes by solid-state dewetting [2,3], i.e., the heat-induced agglomeration of sputtered thin metal films into nanoparticles (NPs) with tunable loading, size, structure, and composition.In this context, I discuss the following aspects: i) How dewetting can be steered to produce model, spatially separated and coherently oriented metal NPs with defined exposed facets [4]; ii) The use of dewetted electrodes to study nanoscale effects such as electronic metal support interactions (EMSI) in electrocatalytic reactions [5]; and iii) possibilities to apply scanning electrochemical techniques, in-situ spectroscopic tools or single-particle probes to investigate surface and interfacial phenomena of dewetted NP electrocatalysts.[1] A.R. Akbashev, ACS Catal. 2022, 12, 8, 4296.[2] C.V. Thompson, Annu. Rev. Mater. Res. 2012, 42, 399.[3] Altomare et al., Chem. Sci. 2016, 7, 6865.[4] Sharma et al., ECS 2023 https://ecs.confex.com/ecs/244/meetingapp.cgi/Paper/180073[5] Harsha et al., ECS 2023 https://ecs.confex.com/ecs/244/meetingapp.cgi/Paper/179874

Oxygen Vacancy Enabled Electronic Structure Engineering of Pt-WO3 Nanosheets toward Highly Efficient BTEX Sensing.

A Pt nanoparticle-immobilized WO3 material is a promising candidate for catalytic reactions, and the surface and electronic structure can strongly affect the performance. However, the effect of the intrinsic oxygen vacancy of WO3 on the d-band structure of Pt and the synergistic effect of Pt and the WO3 matrix on reaction performance are still ambiguous, which greatly hinders the design of advanced materials. Herein, Pt-decorated WO3 nanosheets with different electronic metal-support interactions are successfully prepared by finely tuning the oxygen vacancy structure of WO3 nanosheets. Notably, Pt-modified WO3 nanosheets annealed at 400 °C exhibit excellent benzene series (BTEX) sensing performance (S = 377.33, 365.21, 348.45, and 319.23 for 50 ppm ethylbenzene, benzene, toluene, and xylene, respectively, at 140 °C), fast response and recovery dynamics (10/7 s), excellent reliability (σ = 0.14), and sensing stability (φ = 0.08%). Detailed structural characterization and DFT results reveal that interfacial Ptδ+-Ov-W5+ sites are recognized as the active sites, and the oxygen vacancies of the WO3 matrix can significantly affect the d-band structure of Pt nanoparticles. Notably, Pt/WO3-400 with improved surface oxygen mobility and medium electronic metal-support interaction facilitates the activation and desorption of BTEX, which contributes to the highly efficient BTEX sensing performance. Our work provides a new insight for the design of high-performance surface reaction materials for advanced applications.

Electronic metal-support interactions between zeolite and confined platinum-tin nanoalloy boosting propane dehydrogenation

Zeolite-confined Pt-based bimetallic catalysts have shown great potential in the direct dehydrogenation (PDH) reaction, yet the low affinity of the bimetallic species with the zeolite supports often results in catalytic deactivation during long-term reactions. Creating strong interactions between metals and supports holds the promise to address this challenge. Herein, we report S-1 zeolite confined Pt3Sn bimetallic catalysts that exhibit enhanced activity and stability for PDH through electronic metal-support interactions (EMSI). Notably, the optimized Pt3Sn/S-1 catalyst shows a 310-fold increase in the catalytic stability compared to its SiO2-supported counterpart. Experimental and theoretical studies unveil that the Pt3Sn/S-1 catalyst is characterized by direct Sn–Pt–O–Si(OSi)3 interfacial bonds. The strong chemical bonding leads to electron transfer from Pt3Sn to S-1, signifying the strong EMSI effect that modulates the electronic and chemical properties of Pt3Sn. The presence of EMSI enhances the adsorption of propane and facilitate the desorption of propylene, consequently boosting both the activity and selectivity of the catalyst. This work highlights the profound impact of metal-support interactions for the development of high-performance PDH catalysts.

Multilevel assault dominated by electron-transfer nonradical pathway via electronic metal–support interactions of Bi-C bonds for disinfection

Multilevel assaults on aqueous pathogenic microorganisms were realized by persulfate (PS) activation system with Bi–C based electronic metal-supported interactions (EMSI) of bismuth-embedded carbon chainmail catalyst (Bi@CC) dominated by electron-transfer nonradical pathway. The Bi@CC/PS disinfection system achieved approximately 100 % bacterial inactivation (6.5 log10 cfu/mL) within 35 min. The electron transfer from Bi to the carbon layer via Bi-C bond leading to higher work functions, thus realizing primary assault to the extracellular membrane via bacterial extracellular electron transfer (EET) function. Electron rearrangement of Bi-C is conducive to forming the intermediate complexes (Bi@CC-PS*), leading to higher work functions and enhancing electron transfer pathway (ETP) process to aggravate cell destruction, while radicals (∙OH andSO4∙-) directly attacks the interior cell. The Bi@CC/PS disinfection system possesses excellent environmental adaptability, cycling performance, and safety. This study enriches the heterogeneous mechanism of PS activation and proposes a promising strategy for sewage effluent treatment.

Efficient Electrosynthesis of Urea over Single-Atom Alloy with Electronic Metal Support Interaction.

Urea electrosynthesis from carbon dioxide (CO2) and nitrate (NO3 -) is an alternative approach to traditional energy-intensive urea synthesis technology. Herein, we report a CuAu single-atom alloy (SAA) with electronic metal support interaction (EMSI), achieving a high urea yield rate of 813.6 μg h-1 mgcat -1 at -0.94 V versus reversible hydrogen electrode (vs. RHE) and a Faradaic efficiency (FE) of 45.2 % at -0.74 V vs. RHE. In situ experiments and theoretical calculations demonstrated that single-atom Cu sites modulate the adsorption behavior of intermediate species. Bimetallic sites synergistically accelerate C-N bond formation through spontaneous coupling of *CO and *NO to form *ONCO as key intermediates. More importantly, electronic metal support interaction between CuAu SAA and CeO2 carrier further modulates electron structure and interfacial microenvironment, endowing electrocatalysts with superior activity and durability. This work constructs SAA electrocatalysts with EMSI effect to tailor C-N coupling at the atomic level, which can provide guidance for the development of C-N coupling systems.

Efficient Electrosynthesis of Urea over Single‐Atom Alloy with Electronic Metal Support Interaction

AbstractUrea electrosynthesis from carbon dioxide (CO2) and nitrate (NO3−) is an alternative approach to traditional energy‐intensive urea synthesis technology. Herein, we report a CuAu single‐atom alloy (SAA) with electronic metal support interaction (EMSI), achieving a high urea yield rate of 813.6 μg h−1 mgcat−1 at −0.94 V versus reversible hydrogen electrode (vs. RHE) and a Faradaic efficiency (FE) of 45.2 % at −0.74 V vs. RHE. In situ experiments and theoretical calculations demonstrated that single‐atom Cu sites modulate the adsorption behavior of intermediate species. Bimetallic sites synergistically accelerate C−N bond formation through spontaneous coupling of *CO and *NO to form *ONCO as key intermediates. More importantly, electronic metal support interaction between CuAu SAA and CeO2 carrier further modulates electron structure and interfacial microenvironment, endowing electrocatalysts with superior activity and durability. This work constructs SAA electrocatalysts with EMSI effect to tailor C−N coupling at the atomic level, which can provide guidance for the development of C−N coupling systems.

Kinetic modelling of non-equilibrium plasma enhanced catalytic ammonia decomposition

It is important for the usage of ammonia as energy carrier to achieve ammonia decomposition at low temperature. In the present study, a reactor model of plasma catalytic ammonia decomposition over Fe catalyst at atmospheric pressure is developed in the aspect of plasma and chemical synergies kinetics. The plasma catalytic model accounted for multiple physical mechanisms in electronic and vibrational plasma kinetics and detailed ammonia decomposition mechanisms on the catalyst surface. In addition, a novel view that identify the surface chemisorption enhancement by plasma attributed to charge transfer via EMSI (electronic metal-support interaction) effect is highlighted. The result shows that the synergetic effect of plasma and thermal-catalyst is much greater than that of plasma or catalyst alone on ammonia decomposition, especially at low temperature. It is revealed that the surface desorption of nitrogen is still the rate-limiting step. Moreover, the numerical results also indicate that Langmuir-Hinshelwood reaction via 2 N(s)=>N2 is more likely to dominate the surface desorption of nitrogen in the presence of plasma rather than Eley-Rideal reaction via N + N(s)=>N2. At low electric field, there are infrequent free radicals (NH2, NH and N) and few vibrational ammonia (NH3(v)) generated by the plasma, thus considering that the adsorbed ammonia only undergoes a three-step dehydrogenation reaction. As a consequence, the rate of surface nitrogen desorption with plasma is greater than that with catalyst alone since plasma promotes the chemisorption process of ammonia. This work provides new fundamental insights into the synergistic effect of plasma and catalyst, as well as the direction for the ammonia decomposition catalyst design in plasma.

Boron carbon nitride as efficient oxygen reduction reaction support

The electrocatalytic oxygen reduction reaction (ORR) is crucial for energy conversion systems such as fuel cells and metal-air batteries. Boron carbon nitrogen (BCN) is a novel functional material with a high specific surface area, excellent corrosion resistance, and outstanding electrochemical stability. These properties make BCN an effective ORR catalyst and a promising support for metal catalysts. This study leveraged the strong interaction between BCN and metals to anchor platinum nanoparticles (Pt NPs) onto the BCN surface (Pt/BCN), significantly enhancing the durability of traditional Pt/C catalysts in ORR. The half-wave potential of Pt/BCN is 0.927 V, higher than Pt/XC-72R (0.857 V) and commercial Pt/C (0.879 V). Notably, after 10,000 durability test cycles, the mass activity (MA) of Pt/XC-72R and commercial Pt/C decreased by 67 % and 75 %, respectively. Even after 50,000 cycles, Pt/BCN exhibited only a 54 % decrease in MA. Experimental data and density functional theory calculations confirmed increased electron transfer from Pt to the BCN support, indicating a strong electronic metal-support interaction (EMSI) between Pt and BCN. This strong EMSI effectively anchored the Pt NPs, preventing migration and aggregation during the ORR process. Consequently, our research introduces a novel electrocatalyst support material with significant potential for ORR and broader applications.

Cu NCs@MXene-luminescent Faraday cage and Cu Nanocone/Bi NPs array-based saliva exosome assay for asthma evaluation

In this work, a novel nano-sensing system with luminescent Faraday cage mode has been developed to detect miRNA-221-5p in clinic saliva exosomes to evaluate asthma. Firstly, copper nanoclusters (Cu NCs) were synthesized in situ on the defects in Ti3CN nanosheets based on the nanoconfinement effect. Due to the Electronic metal-support interactions (EMSI) between MXene and the anchored Cu NCs, Cu NCs@MXene displayed the strong luminescence performance, high electrochemical activity and good stability properties. Furthermore, MXene nanosheets with good conductivity and flexibility was used to expand the outer Helmholtz plane and improve the sensing ability. Meanwhile, Cu nanocone/Bi nanoparticles (NPs) arrays were constructed by step-by-step electrodeposition. Due to the surface plasmon coupling effect, the Cu nanocone/Bi NPs arrays can convert the electrochemiluminescence (ECL) signal of Cu NCs@MXene-Faraday cage into the directional emission with 13.4-fold enhancement. Finally, a thin phospholipid film and capture DNA were modified on the surface of the Cu nanocone/Bi NPs array as the sensing interface to detect miRNA-221-5p in saliva exosomes. The designed nano-sensing system had a detection range was 1.0 × 10-16 ∼ 1.0 × 10-8 mol/L with the detection limit of 34 aM. Finally, the biosensor has been successfully employed to evaluate asthma in the clinical analysis.

Adjusting Ag0 on oxygen-deficient Ag/MnO2 through electronic metal-support interaction to enhance mineralization of toluene in post-plasma catalytic system

While nonthermal plasma (NTP) technology exhibits notable efficacy in removing volatile organic compounds (VOCs), its practical application is impeded by a restricted carbon dioxide (CO2) selectivity. In this work, Ag-loaded α-MnO2 nanorods with strong electronic metal-support interaction (EMSI) were synthesized to enhance the mineralization of toluene in post-plasma system (PPC). EMSI was constructed between Ag species and MnO2 by anchoring Ag on hydroxyl groups. Increasing Ag loading facilitated the generation of oxygen vacancies, which promoted electron transfer from MnO2 to Ag sites, reinforcing EMSI and favoring the formation of Ag0. The results showed that the 3% Ag-loaded α-MnO2 nanorods exhibited better activity than bare MnO2, with a remarkable boost in CO2 selectivity to 77.5%, far exceeding the 33% CO2 selectivity of MnO2. It was concluded that both oxygen vacancies and Ag0 affected the toluene conversion by enhancing the conversion of ozone (O3) to reactive oxygen species (ROS). Through in-situ DRIFTS, it was found that Ag0 transformed O3 to a higher concentration of atomic oxygen (O*), capable of degrading organic intermediates to CO2. Additionally, Ag0 facilitated the direct ring-opening of adsorbed toluene. This research introduces a novel method for designing catalysts with EMSI to improve the mineralization of VOCs.

Improvement on electrochemiluminescence properties of graphite carbon nitride by metal oxidation state regulation

AbstractReasonable design is of great significance for improving the performance of electrochemiluminescence (ECL) co‐reactant accelerators. The different d‐band structure of metal single atoms will produce different oxidation states, which may change the adsorption of reaction intermediates to the catalyst and affect its catalytic activity. In this study, we have demonstrated that the ECL performances of graphite carbon nitride (CN) can be promoted by modulating the metal oxidation states of co‐reaction accelerator for the first time. The oxidation states of Au were modulated by the different electronic metal–support interaction (EMSI) between the co‐reaction accelerator (Au single atoms, Au nanoparticles [Au NPs]) and CN, and the effects of Au oxidation states on the ECL performances of CN were investigated. Comparison to pristine CN and CN nanosheets supported Au nanoparticles (Au NPs/CN), stronger and more stable ECL intensity of CN nanosheets supported Au single‐atoms (AuS/CN) was obtained. The ECL signal of AuS/CN was about 32.2 times that of the original CN, and 2.8 times that of Au NPs/CN in the same Au loading content (0.8%). Detailed mechanism revealed that AuS/CN with higher Au oxidation state has better conductivity and stronger catalytic activity, which promotes the electric reduction of CN and S2O82−, increases the lifetime of the excited state CN*, and significantly improves the ECL performance of CN. In addition, this work provides a detailed understanding of the essence of EMSI for the ECL intensity amplification and established a feasible method for the improvement of ECL capacities of co‐reactant accelerators.

Dewetting of Pt Nanoparticles Boosts Electrocatalytic Hydrogen Evolution Due to Electronic Metal‐Support Interaction

AbstractSolid‐state dewetting is the heat‐induced agglomeration of thin metal films into defined nanoparticles (NPs). Dewetted Pt nanoparticles are investigated on F‐doped SnO2 (FTO) substrates as model binder‐free electrodes for the hydrogen evolution reaction (HER). Dewetting of Pt films into particles exposes the FTO substrate and the metal/support (Pt‐FTO) contact line. Despite the decrease in Pt electrochemical surface area (ECSA) upon dewetting, dewetted NPs show a >3‐fold increase in ECSA‐normalized HER activity compared to as‐deposited nanocrystalline Pt films. Electrodes designed with dewetted Pt NPs of different sizes show that the HER activity does not only correlate with the ECSA but also increases with increasing the Pt‐FTO contact line length. The smaller the NPs, the larger the Pt‐FTO contact line, and the higher the activity. This effect is ascribed to electronic metal‐support interaction (EMSI), due to electron transfer from FTO to Pt. It is proposed that EMSI effects alter the electronic structure of Pt sites near the Pt‐FTO contact line, facilitating the H2 evolution kinetics. When NPs are a few nm‐sized, a large mass fraction of Pt is affected by EMSI, resulting in a further increase of HER activity compared to NPs ≥10 nm despite the lower ECSA.

TS-1 zeolite encapsulated Pt clusters with enhanced electronic metal-support interaction of Pt−O(H)−Ti for nearly-zero-carbon-emitting photocatalytic hydrogen production from methanol

Photocatalytic H2 production from methanol is sustainable, yet challenges remain in avoiding carbon-containing gaseous by-products. Titanium silicalite-1 (TS-1) zeolite possesses attractive photocatalytic performance, but lack of modification strategies due to its microporous framework. Herein, we developed a pre-anchoring strategy to confine ultra-small Pt clusters inside TS-1 with ultra-low loading (0.2 mol%), in which Pt were anchored in Ti−OH nests by electronic metal-support interaction (EMSI). The optimal catalyst achieved a remarkable H2 generation rate of 63.2 mmol g–1 h–1 in CH3OH solutions, along with the production of high-value chemical HCHO as the oxidation product with 96.9% selectivity. Investigations reveal that the EMSI between Pt and Ti facilitated the selective decomposition of CH3OH to H2 and HCHO, leading to a nearly zero-carbon-emission process. Accordingly, we propose a light-driven carbon-negative "CO2→CH3OH→H2" route, coupling CO2 utilization and green H2 production with CH3OH as the intermediate, therefore offering a new perspective for "liquid sunshine".

Metal-support interface engineering for stable and enhanced hydrogen evolution reaction

Hydrogen has emerged as a green and sustainable pathway towards achieving global decarbonization and net-zero emissions, intensely driving the need for efficient hydrogen production protocols. Electrocatalytic hydrogen evolution reaction (HER) holds great potential as a scalable, eco-friendly and safe avenue for efficient hydrogen production. However, the large-scale implementation of electrocatalytic HER is substantially challenged by the high-cost and unstable materials that are mainly fabricated from noble metals, e.g., Pt and Pd. Given this challenge, we adopted an interface engineering strategy to immobilize nanoscale Pt particles within the framework of nitrogen-doped CNTs, namely Pt@N-CNTs, where electronic metal-support interaction (EMSI) plays an important role in enabling orbital rehybridization and regulating the charge transfer through the metal-support interface, thereby considerably improving the electrocatalytic activity. With limited content of noble metals, our developed Pt@N-CNTs delivered superior HER performance with an ultralow overpotential of 5.8 mV at 10 mA cm−2 and demonstrated a high mass activity of 12.72 A mgPt−1 at an overpotential of 50 mV as well as excellent stability under harsh acidic conditions. At 500 mA cm−2, Pt@N-CNTs surprisingly exhibited an overpotential of 55.2 mV, outperforming that of commercial 20 wt% Pt/C catalysts (131.5 mV). Importantly, we established a straightforward, scalable, and time-saving microwave reduction strategy, alluding to its promising commercial viability. This work therefore sheds light on the development of high-performance electrocatalysts for hydrogen evolution and water electrolysis.

Modulation effect of support on active metals in the Fe-Ni based catalysts: Insight into the electronic metal-support interaction (EMSI) effect in the CO-SCR reaction

Supported catalysts have been extensively investigated and implemented in the industry due to their cost-effectiveness and promising catalytic performance. However, due to the general inert nature of the support itself, its role in the catalyst performance is often neglected and therefore not well understood despite the consideration of the physical properties of the support. This study applies the concept of electronic metal-support interaction (EMSI) to explore the impact of various supports on the active metals in Fe-Ni-based catalysts for the CO-selective catalytic reduction reaction. Through density functional theory calculations and several advanced characterizations, it can be confirmed that the EMSI effect can modify the valence states of active metals and foster interaction between different active metals, thereby influencing the reactant adsorption and catalyst performance greatly. These findings highlight the significant impact of the support on the chemical states of active metals, having far-reaching implications for designing and optimizing the supported industrial catalysts.

Selective Orbital Coupling: An Adsorption Mechanism in Single-Atom Catalysis.

Quantitative understanding of the chemisorption on single-atom catalysts (SACs) by their electronic properties is crucial for the catalyst design. However, the physical mechanism is still under debate. Here, the CO catalytic oxidation on single transition metal (i.e., Sc, Ti, V, Cr, Mn, Fe, Co, Ni) dopants is used as a theoretical model to explore the correlations between the characteristics of electronic structures and the chemisorption on SACs. For these metal dopants, their atomic d orbitals form several nondegenerate and localized electronic states that are found to be selectively coupled with the π* orbital of the adsorbed O2, which we defined as selective orbital coupling. Based on the selective orbital coupling, we find that the alignment between the selected d state and the π* state determines the bond strength, regardless of the electron occupation number of the selected d states; the electron transfer to form M-O bonding can be provided by the support. Such electron transfer can be related with the electronic metal-support interaction. We attribute the origin of the chemisorption mechanism to the coexistence of the localized orbital of the single transition metal and the continuous energy band of the Au support. Finally, we illustrate how this mechanism dominates the variation trend of the reaction barriers. Our results unravel a fundamental adsorption mechanism in SAC systems.

Electronic Metal-Support Interactions Boost *OOH Intermediate Generation in Cu/In2Se3 for Electrochemical H2O2 Production.

Two-electron oxygen reduction reaction (2e- ORR) is a promising method for the synthesis of hydrogen peroxide (H2O2). However, high energy barriers for the generation of key *OOH intermediates hinder the process of 2e- ORR. Herein, we prepared a copper-supported indium selenide catalyst (Cu/In2Se3) to enhance the selectivity and yield of 2e- ORR by employing an electronic metal-support interactions (EMSIs) strategy. EMSIs-induced charge rearrangement between metallic Cu and In2Se3 is conducive to *OOH intermediate generation, promoting H2O2 production. Theoretical investigations reveal that the inclusion of Cu significantly lowers the energy barrier of the 2e- ORR intermediate and impedes the 4e- ORR pathway, thus favoring the formation of H2O2. The concentration of H2O2 produced by Cu/In2Se3 is ~2 times than In2Se3, and Cu/In2Se3 shows promising applications in antibiotic degradation. This research presents a valuable approach for the future utilization of EMSIs in 2e- ORR.

Electronic Metal‐Support Interactions Boost *OOH Intermediate Generation in Cu/In2Se3 for Electrochemical H2O2 Production

AbstractTwo‐electron oxygen reduction reaction (2e− ORR) is a promising method for the synthesis of hydrogen peroxide (H2O2). However, high energy barriers for the generation of key *OOH intermediates hinder the process of 2e− ORR. Herein, we prepared a copper‐supported indium selenide catalyst (Cu/In2Se3) to enhance the selectivity and yield of 2e− ORR by employing an electronic metal–support interactions (EMSIs) strategy. EMSIs‐induced charge rearrangement between metallic Cu and In2Se3 is conducive to *OOH intermediate generation, promoting H2O2 production. Theoretical investigations reveal that the inclusion of Cu significantly lowers the energy barrier of the 2e− ORR intermediate and impedes the 4e− ORR pathway, thus favoring the formation of H2O2. The concentration of H2O2 produced by Cu/In2Se3 is ~2 times than In2Se3, and Cu/In2Se3 shows promising applications in antibiotic degradation. This research presents a valuable approach for the future utilization of EMSIs in 2e− ORR.

Confined cobalt single‐atom catalysts with strong electronic metal‐support interactions based on a biomimetic self‐assembly strategy

AbstractDesigning high‐performance and low‐cost electrocatalysts for oxygen evolution reaction (OER) is critical for the conversion and storage of sustainable energy technologies. Inspired by the biomineralization process, we utilized the phosphorylation sites of collagen molecules to combine with cobalt‐based mononuclear precursors at the molecular level and built a three‐dimensional (3D) porous hierarchical material through a bottom‐up biomimetic self‐assembly strategy to obtain single‐atom catalysts confined on carbonized biomimetic self‐assembled carriers (Co SACs/cBSC) after subsequent high‐temperature annealing. In this strategy, the biomolecule improved the anchoring efficiency of the metal precursor through precise functional groups; meanwhile, the binding‐then‐assembling strategy also effectively suppressed the nonspecific adsorption of metal ions, ultimately preventing atomic agglomeration and achieving strong electronic metal‐support interactions (EMSIs). Experimental characterizations confirm that binding forms between cobalt metal and carbonized self‐assembled substrate (Co–O4–P). Theoretical calculations disclose that the local environment changes significantly tailored the Co d‐band center, and optimized the binding energy of oxygenated intermediates and the energy barrier of oxygen release. As a result, the obtained Co SACs/cBSC catalyst can achieve remarkable OER activity and 24 h durability in 1 M KOH (η10 at 288 mV; Tafel slope of 44 mV dec−1), better than other transition metal‐based catalysts and commercial IrO2. Overall, we presented a self‐assembly strategy to prepare transition metal SACs with strong EMSIs, providing a new avenue for the preparation of efficient catalysts with fine atomic structures.

Solvent-free selective hydrogenation of nitroaromatics to azoxy compounds over Co single atoms decorated on Nb2O5 nanomeshes

The solvent-free selective hydrogenation of nitroaromatics to azoxy compounds is highly important, yet challenging. Herein, we report an efficient strategy to construct individually dispersed Co atoms decorated on niobium pentaoxide nanomeshes with unique geometric and electronic properties. The use of this supported Co single atom catalysts in the selective hydrogenation of nitrobenzene to azoxybenzene results in high catalytic activity and selectivity, with 99% selectivity and 99% conversion within 0.5 h. Remarkably, it delivers an exceptionally high turnover frequency of 40377 h–1, which is amongst similar state-of-the-art catalysts. In addition, it demonstrates remarkable recyclability, reaction scalability, and wide substrate scope. Density functional theory calculations reveal that the catalytic activity and selectivity are significantly promoted by the unique electronic properties and strong electronic metal-support interaction in Co1/Nb2O5. The absence of precious metals, toxic solvents, and reagents makes this catalyst more appealing for synthesizing azoxy compounds from nitroaromatics. Our findings suggest the great potential of this strategy to access single atom catalysts with boosted activity and selectivity, thus offering blueprints for the design of nanomaterials for organocatalysis.