Bimetallic Sites Research Articles

Polyethyleneimine coated AgInS2 quantum dots for efficient CO2 photoreduction to C2H6

Quantum dots exhibit great potential in photocatalytic CO2 conversion into value-added fuels to achieve a carbon-neutral society, owing to their unique optical properties and tunable surface chemistry. However, the generation of multi-carbon hydrocarbon products remains a grand challenge. Herein, polyethyleneimine (PEI) coated AgInS2 quantum dots (AgInS2@PEI QDs) are designed for the photo-catalytic conversion of CO2 to C2 products. It is found that the yield and selectivity of C2H6 can be significantly enhanced by regulating the content of Ag and PEI in AgInS2@PEI QDs. Under the optimal conditions, C2H6 yield reaches 63 μmol g-1, and the electron selectivity is 30.3 %. A mechanistic study reveals that PEI effectively promotes the accumulation of photogenerated electrons, and the CO-enriched local environment caused by Ag boosts CC coupling on asymmetric bimetallic sites. This work offers new insight on the design of efficient quantum dot photocatalysts for CO2 conversion to C2 products.

Two-dimensional QDs-Co-CuS1-x/Ti3C2/TiO2 heterojunction with synergistic unsaturated bimetal sites and sulfur vacancies for highly selective photocatalytic CO2 reduction

The primary factors that determine the efficiency and selectivity of multi-electron photoreduction of CO2 include the chemical properties of the active sites, as well as the kinetics of charge separation and transfer. Herein, a novel two-dimensional QDs-Co-CuS1-x/Ti3C2/TiO2 heterojunction is developed, with Co-CuS1-x quantum dots serving as cocatalysts and Ti3C2 MXene as an effective electron transfer channel. The anchoring effect of Ti3C2 facilitates the formation of robust TiS bonds with Co-CuS1-x, thereby promoting efficient separation and transfer of photoelectrons to the Co-Cu bimetallic active sites. This process enhances the local electron density at these sites and accelerates the kinetics of electron transfer to absorbed CO2. The recyclability of the Co-Cu sites is also significantly enhanced by continuous photoelectron injection. Importantly, DFT calculations indicate that the synergistic dual sites involving highly exposed Co-Cu and S vacancies promote rate-determining step from COO* to COOH*, which may account for the highly selective photoreduction of CO2-to-CO. Benefitting from the synergic effects of the active sites and efficient separation of carriers, the optimized Co-CuS1-x/Ti3C2/TiO2 exhibits a satisfactory CO photoreduction rate of 30.8 µmol∙g−1∙h−1, with an excellent selectivity of 87.9 % and apparent quantum yield of 0.61 % in the absence of any sacrificial reagents, which is 6.5 times higher than Co-CuS1-x, 54.0 times than Ti3C2Tx/TiO2.

Utilizing cationic vacancy defects to switch oxygen evolution mechanisms on atomically dispersed ru for enhanced acidic catalytic performance

Achieving the oxide path mechanism (OPM) through bimetallic catalysis is a promising approach for developing highly active and stable electrocatalysts for the acidic oxygen evolution reaction (OER). However, optimizing atomic-level and local ligand structures to enhance the synergistic interaction of bimetallic active sites still remains a challenge. Here, through the introduction of tetrahedral Co (Cotet) cationic defects and selectively substituting atomic Ru on the octahedral Co (Cocot) sites in Co3O4, we present an effective strategy to significantly enhance the orbital hybridization and the synergistic interaction of bimetallic active sites. Experimental and theoretical calculations show that this approach facilitates thermodynamic mechanism for diatomic oxygen formation. Cationic defects are utilized as electron acceptors, facilitating the transfer of electrons from Ru to Co, enhancing the overlap in the density of states, and optimizing the d-band center of Ru and Co. Therefore, the orbital hybridization and synergistic effect of bimetallic active sites are improved. Remarkably, the catalyst with a minimal Ru mass loading of around 45.5 μg∙cm−2, featuring a low overpotential of 150 mV and a minimal potential decay rate of just 0.35 mV∙h−1 at 10 mA∙cm−2. Our work offers an effective strategy to enhance the synergistic interaction of bimetallic sites, and the mechanism of cationic defects improve the acidic OER performance of bimetallic sites has been thoroughly investigated, which is expected to contribute to clean energy production.

Polarized Bimetallic Site Synergy in Ionic Structures of Cu(II), Fe(III), and Mn(III) Porphyrins: Electrochemistry and Catalytic Hydrogenation of Nitroaromatics.

Binuclear catalytic sites attained in a controlled way with complementary and cooperative metal ion centers are highly relevant in the development of new or enhanced catalytic processes. Herein, binuclear sites carrying Fe(III), Cu(II), or Mn(III) metal ions with a polarized structure have been prepared using the ionic self-assembly of oppositely charged metalloporphyrins. Binary porphyrin structures (BIPOS) have been prepared based on metalloporphyrin cations carrying pyridinium or methylpyridinium groups in conjugation with metalloporphyrin anions carrying sulfonatophenyl groups. BIPOS carrying [cation/anion] tecton pairs of [Cu/Fe], [Fe/Cu], [Cu/Cu], [Fe/Fe], [Mn/Fe], [Fe/Mn], and [Mn/Mn] have been compared. Electrochemical interaction and enhanced catalytic behavior are noticeable for BIPOS [Fe/Cu], [Fe/Fe], and [Mn/Fe] carrying a Fe center and [less electronegative/more electronegative] metal ion centers in the [cation/anion] porphyrin ionic pairs. For high-performance BIPOS, cyclic voltammograms showed a greater separation of the cathodic and anodic peaks, within ΔEp = 0.095-0.125 V, and the rate constants for the catalytic reduction of 4-nitrophenol were within k = 0.380-0.535 min-1/mg of catalyst, significantly superior to the related individual metalloporphyrins. Inverse heterobimetallic [Cu/Fe] and [Fe/Mn] and the homometallic BIPOS [Cu/Cu] and [Mn/Mn] were significantly less active or inefficient. A [Fe/Cu] material could be reused in at least 5 catalytic cycles, maintaining catalytic activity; the best catalysts were also active in the reduction of nitrobenzene to aniline in mild conditions (visible light, 30 °C, 0.5 mol % catalyst), and an [Fe/Fe] catalyst showed 100% aniline yield after 2 h.

Chemically Modified HKUST-1(Cu) for Gas Adsorption and Separation: Mixed-Metal and Hierarchical Porosity.

The archetypical metal-organic framework (MOF), HKUST-1, has been systematically modified in both its organic and inorganic building blocks to introduce diversity in the metal centers and create defects within the network, achieving a variety of bimetallic hierarchical structures. These modifications changed the affinity of the MOFs for acid gases. The introduction of bimetallic sites mostly affects CO2 adsorption, while the hierarchical structure generates an increase in SO2 uptake capacity, allowing better performance in the separation of binary mixtures of these gases near room temperature. Notably, the synthesized HH-Cu100 material exhibited an exceptionally high IAST SO2/CO2 (10:90) selectivity of 3420 at 298 K, outperforming benchmark MOFs with open metal sites.

Iron-Induced Localized Oxide Path Mechanism Enables Efficient and Stable Water Oxidation.

The sluggish reaction kinetics of the anodic oxygen evolution reaction (OER) and the inadequate catalytic performance of non-noble metal-based electrocatalysts represent substantial barriers to the development of anion exchange membrane water electrolyzer (AEMWE). This study performed the synthesis of a three-dimensional (3D) nanoflower-like electrocatalyst (CFMO) via a simple one-step method. The substitution of Co with Fe in the structure induces a localized oxide path mechanism (LOPM), facilitating direct O-O radical coupling for enhanced O2 evolution. The optimized CFMO-2 electrocatalyst demonstrates superior OER performance, achieving an overpotential of 217 mV at 10 mA cm-2, alongside exceptional long-term stability with minimal degradation after 1000 h of operation in 1.0 M KOH. These properties surpass most of conventional noble metal-based electrocatalysts. Furthermore, the assembled AEMWE system, utilizing CFMO-2, operates with a cell voltage of 1.65 V to deliver 1.0 A cm-2. In situ characterizations reveal that, in addition to the traditional adsorbate evolution mechanism (AEM) at isolated Co sites, a new LOPM occurred around the Fe and Co bimetallic sites. First-principles calculations confirm the LOPM greatly reduced the energy barriers. This work highlights the potential of LOPM for improving the design of non-noble metal-based electrocatalysts and the development of AEMWE.

Iron‐Induced Localized Oxide Path Mechanism Enables Efficient and Stable Water Oxidation

The sluggish reaction kinetics of the anodic oxygen evolution reaction (OER) and the inadequate catalytic performance of non‐noble metal‐based electrocatalysts represent substantial barriers to the development of anion exchange membrane water electrolyzer (AEMWE). This study performed the synthesis of a three‐dimensional (3D) nanoflower‐like electrocatalyst (CFMO) via a simple one‐step method. The substitution of Co with Fe in the structure induces a localized oxide path mechanism (LOPM), facilitating direct O–O radical coupling for enhanced O2 evolution. The optimized CFMO‐2 electrocatalyst demonstrates superior OER performance, achieving an overpotential of 217 mV at 10 mA cm–2, alongside exceptional long‐term stability with minimal degradation after 1000 h of operation in 1.0 M KOH. These properties surpass most of conventional noble metal‐based electrocatalysts. Furthermore, the assembled AEMWE system, utilizing CFMO‐2, operates with a cell voltage of 1.65 V to deliver 1.0 A cm–2. In situ characterizations reveal that, in addition to the traditional adsorbate evolution mechanism (AEM) at isolated Co sites, a new LOPM occurred around the Fe and Co bimetallic sites. First‐principles calculations confirm the LOPM greatly reduced the energy barriers. This work highlights the potential of LOPM for improving the design of non‐noble metal‐based electrocatalysts and the development of AEMWE.

A “pre-constrained bimetallic” strategy for the preparation of efficient synergistic electrocatalytic hydrogen evolution catalysts

A micro-sized bimetallic nanoparticles (NPs) catalyst that anchors a mixture of Co and Pd atoms onto a porous nitrogen-doped carbon (NC) framework for electrocatalysis of hydrogen evolution reaction (HER). Programmable metal-porphyrin ligands serve as building blocks for attaching bimetallic sites (consisting of Co and Pd) in metal-organic frameworks for decentralized anchoring before pyrolysis. Experimental studies have shown the interaction between Pd and Co in Co20/Pd20-NC results in electron depletion near Co and electron accumulation near Pd, respectively. Therefore, there is an asymmetric local electron density distribution on the bimetallic site of Co20/Pd20-NC, which improves the activity of the catalyst. To achieve a current density of 10mA·cm-2 in both acidic and alkaline conditions, the Co20/Pd20-NC exhibits noteworthy HER characteristics with overpotentials of 23 and 52mV, respectively. The Co20/Pd20-NC prepares in this study which shows good characteristics in the process of electrocatalytic hydrogen evolution, and has a good application prospect.

MOF nanoflowers-based flexible portable NO sensors for human airway inflammation detection

The concentration of nitric oxide (NO) in exhaled breath is linked to respiratory diseases, requiring precise detection. Traditional two-dimensional (2D) carbon-based materials used in chemiresistive gas sensors suffer from high detection limits due to a lack of functional sites, while metal oxide sensors are limited by poor selectivity and high operating temperatures, restricting their development. Recently, metal–organic frameworks (MOFs) have emerged as an effective material for NO monitoring due to their superior selectivity; however, their inherent insulating properties hinder practical use. In this study, we synthesized Ni, Co-MOF-74-Carbon Nanotube (CNT) heterostructured nanoflowers, leveraging their bimetallic active sites and large specific surface area to enhance NO adsorption. This composite material, integrated with breathable nanofibrous membranes through physical deposition, exhibits high selection to NO, achieving a linear response range of 30 to 1000 ppb at room temperature and a limit of detection (LOD) of 18.6 ppb. This sensor can accurately detect NO levels in the exhaled breath of both healthy and diseased individuals, confirming its potential for respiratory disease diagnosis. Additionally, we developed a portable device integrating the Ni, Co-MOF-74-CNT- polyacrylonitrile (PAN) membrane, a microcontroller unit (MCU), and a Bluetooth module for real-time NO detection. The systematic design and successful validation of this portable gas sensor pave the way for future home-based real-time monitoring of airway inflammation.

Integration TiO2 Nanosheets into Defect Engineered Zr-Based MOF for Highly Selective and Efficient Photocatalytic Conversion of CO2 to Ethane

MOFs have shown promising activities in the photocatalytic reduction of CO2. However, their utility has been primarily limited to C1 products, and high-value C2 chemicals have rarely been achieved due to requirement of a large quantity of electron supplying and the slow kinetic of C–C coupling. In particular, there is a significant scarcity of the research on MOF-catalyzed photo-reduction of CO2 to ethane. To address this challenge, we have developed MOF composites by incorporating TiO2 nanosheets into linker defective Zr-based UiO-67 MOFs (denoted as TiO2(X)@UiO-67). These as-synthesized MOFs, featuring charge-polarized active sites (Zr–O–Ti) at the interface between UiO-67 and TiO2, exhibited a remarkable performance in the photocatalytic conversion of CO2 to ethane under visible light illumination. By screening three isostructural TiO2(X)@UiO-67 MOFs with 1.25%, 1.75%, and 2% Ti wt, we discovered a direct relationship between increasing the level of active bimetallic sites and both efficiency and selectivity. Notably, TiO2(2)@UiO-67 resulted C2H6 productivity of 79.3 µmolh-1g-1 with complete selectivity, which to the best of our knowledge is the most efficient MOF catalytic performance reported to date. This work suggests a promising approach for the design of highly efficient photocatalysts for the CO2 reduction to C2 product.

Modulating charge transfer and constructing synergistic bimetallic active sites for CO-SCR reactions in inverse spinel

The selective catalytic reduction of NO by CO (CO-SCR) are frequently catalyzed by spinel due to its exceptional stability and redox capabilities. In this research, a ternary metal-based inverse spinel catalyst Cu0.67Mn0.33Fe2O4 was synthesized utilizing the glycerol self-templating technique. Some Fe3+ (Fe3+Td) sites are transferred to vacant octahedral sites through the occupancy of tetrahedral sites by Mn species. Mn3+ (Mn3+Td) sites synergistically interact with Cu2+ and Fe3+ ions on the octahedral sites to promote charge transfer, producing numerous oxygen-defective and highly mobile oxygen species and constructing Cu+-Ov-Fe2+ active sites on the surface. Various characterizations demonstrated that Cu+-Ov-Fe2+ has greater catalytic activity, resistance to alkali metals, and water toxicity than the Cu2+-Ov-Fe2+ active site of CuFe2O4. In situ DRIFTS further revealed the reaction mechanism of the ternary metal-based inverse spinel catalyst, and this study provides novel perspectives on the development of Cu-based catalysts for CO-SCR.

Cu(I)-Induced 'Click Reaction' Involving Coordination and Covalent Assembly of Hybrid Borates for the Electrocatalytic CO2 Reduction.

The design and synthesis of hybrid borates by the organic ligand modification method are urgent and undeveloped areas of research. It is difficult to directly integrate organoboronic acids within inorganic borate chemistry by adopting the traditional preparation approaches. This work reports a facile synthetic method to synthesize a large family of pyrazole molecule-protected borates in a rapid and precise manner under mild conditions. A unique cyclic eight-membered B4O4-ring has been identified as the cluster core for all these hybrid borates with two different conformations (boat and crown). This strategy can be applied to a system of pyrazolyl molecules to generate such hybrid borates in two independent routes from organoboronic or inorganic boric acids. Furtherly, the mechanism of 'click reaction' between boric acid and pyrazole induced by copper ions has been proposed based on the synthetic conditions and the structure of intermediate. Due to the bimetallic Cu sites and the functional surfaces, these materials can be used as electrocatalysts for CO2 reduction reaction and efficiently enhance the selectivity of HCOOH and C2H4. Our strategy can be regarded as a typical template technique for organic molecule-protected borates.

Cu(I)‐Induced ‘Click Reaction’ Involving Coordination and Covalent Assembly of Hybrid Borates for the Electrocatalytic CO2 Reduction

AbstractThe design and synthesis of hybrid borates by the organic ligand modification method are urgent and undeveloped areas of research. It is difficult to directly integrate organoboronic acids within inorganic borate chemistry by adopting the traditional preparation approaches. This work reports a facile synthetic method to synthesize a large family of pyrazole molecule‐protected borates in a rapid and precise manner under mild conditions. A unique cyclic eight‐membered B4O4‐ring has been identified as the cluster core for all these hybrid borates with two different conformations (boat and crown). This strategy can be applied to a system of pyrazolyl molecules to generate such hybrid borates in two independent routes from organoboronic or inorganic boric acids. Furtherly, the mechanism of ‘click reaction’ between boric acid and pyrazole induced by copper ions has been proposed based on the synthetic conditions and the structure of intermediate. Due to the bimetallic Cu sites and the functional surfaces, these materials can be used as electrocatalysts for CO2 reduction reaction and efficiently enhance the selectivity of HCOOH and C2H4. Our strategy can be regarded as a typical template technique for organic molecule‐protected borates.

Ag–Pt Alloy Nanoparticles Modified Zn‐Based Nanosheets for Highly Selective CO2 Photoreduction to CH4

AbstractMulti‐electron involved photoreduction of CO2 to hydrocarbon fuels is a long‐standing challenge, particularly in manipulating the selectivity of the target products. Here, a novel Ag–Pt bimetallic alloy on Zn‐based supports by photo‐deposition is designed for photocatalytic CO2 reduction to CH4 without any additives. This photocatalyst exhibits ≈ 98.9% selectivity for CH4. Experimental and theoretical calculations demonstrated that the excellent performance of the photocatalyst can be attributed to the localized surface plasmon resonance effect of metals, as well as the synergistic effects of the bimetallic sites. These factors are found to be beneficial not only for capturing solar radiation and facilitating electron migration but also for promoting the adsorption and activation of CO2 and the protonation of *CO. As a result, the photocatalyst achieved high selectivity and activity of photoreduction of CO2 to CH4. This work provides insights into the design of photocatalysts with highly selective target products for CO2 reduction.

Designing Robust Single Atom Catalysts by Three-in-One Strategy: Sub-1-nm Space Confining, Bimetallic Bonding and Reaction-Induced Forming Active Sites.

It is imperative to design robust single atom catalysts (SACs) that maintain the stability of the active component under diverse reaction conditions and prevent aggregation or deactivation. Confining the single atom active site within sub-nanometer (sub-1-nm) spaces has proven effective in enhancing the stability and activity of the catalyst, owing to the strong constraints and regulations imposed on atomic behavior at this scale. Bimetallic bond atomic sites, comprising two distinct metal compositions, often exhibit unique electronic structures and catalytic properties. Designing SACs under reaction-induced conditions, such as varying temperatures, pressures, and atmospheres, can facilitate a deeper understanding of the formation and migration behavior of active sites in real reactions, as well as the optimization mechanisms for performance enhancement. The objective of this review is to promote a robust SAC design strategy that encapsulates bimetallic bonding active sites within sub-1-nm spaces and investigates catalyst preparation and performance under reaction-induced conditions. This design strategy is anticipated to bolster the catalytic activity and stability of the catalyst while also offering fresh perspectives and optimization avenues for the catalytic processes involved in practical chemical reactions.

Modulating NFO@N‐MWCNTs/CC Interfaces to Construct Multilevel Synergistic Sites (Ni/Fe‐O‐N‐C) for Multi‐Heavy Metal Ions Sensing

AbstractA hierarchical heterogeneous composite electrode of NiFe2O4@nitrogen‐doped multi‐walled carbon nanotubes/carbon cloth (NFO@N‐MWCNTs/CC) is prepared via a dip‐coating method, followed by a hydrothermal process. The flexible carbon cloth (CC) substrate provides robust support and the cross‐linked nitrogen‐doped multi‐walled carbon nanotubes (N‐MWCNTs) on the CC form a highly porous network with a large specific area that facilitates electron‐transfer. The stable support strengthens the framework and prevents pore structure disorder within the porous network, that could lead to the structural instability of the active sites. The decorated NiFe2O4 nanoparticles offer abundant active sites for enhanced electrocatalytic activity. Benefiting from the synergistic effect of the 3D hierarchical heterogeneous microstructure and multilevel bimetallic oxide active site (Ni/Fe‐O‐N‐C) constructs, the NFO@N‐MWCNTs/CC electrode achieves stable detection of multiple heavy metal ions (HMIs) with high reproducibility. The modified electrode allowed stable detection of multiple heavy metal ions with high reproducibility. The sensitivities of the electrode for Cd(II), Pb(II), Bi(III), and Hg(II) are 344.98, 441.02, 176.484, and 371.099 µA µm−1, respectively. The assay recoveries ranged from 95.3% to 106.8%, highlighting its practical applicability. This study provides innovative composites and theoretical insights to facilitate further advances in the simultaneous high‐performance detection of heavy metal ions.

Crystal plane engineering-tailored Co-Ni bimetallic sites in CoNiO2 to achieve efficient photocatalytic CO2 reduction

Aligning the atomic structure of catalyst by the crystal-plane engineering is an effective strategy to enhance the photocatalytic activity. In this paper, the CoNiO2 nanosheets (NSs) with (200) and nanorods (NRs) with (111) crystal planes were successfully prepared through a simple hydrothermal method for CO2 photoreduction. The experimental results indicated that the CNO NRs had excellent CO2 photoreduction performance. The CO and CH4 yields over CNO NRs were about 48.66 and 5.84 μmol·g−1·h−1, which were about 2.62 and 2.61 times stronger than that of CNO NSs. Moreover, it was also about 10.70 and 6.25 times as good as the TiO2 commercial powder, respectively. Experimental and theoretical calculations demonstrated that the Co-Ni bimetallic sites on the (111) crystal plane of CNO NRs can effectively enhance the CO2 adsorption and activation ability compared with the single Ni site on the (200) crystal plane of CNO NSs. Besides, the energy barrier required for the development of the critical intermediate *COOH from *CO2 was greatly reduced on the Co-Ni bimetallic sites, thereby improving the CO2 photoreduction activity. The reaction paths were inferred by in-situ FTIR and 13C isotope tracer techniques, and finally a potential enhancement mechanism of the crystal plane engineering induces bimetallic sites to promote CO2 adsorption and activation process has been proposed.

Constructing Hydrangea-Like Iron-Cobalt Phosphides via Boron-Assisted Strategy as an Efficient Catalyst for Water Splitting at High Current Density.

Finding suitable bifunctional catalysts for industrial hydrogen production is the key to fully building a hydrogen energy society. In this study, we present a novel approach to modifying the surface morphology of electrodeposited cobalt phosphide (CoP). Specifically, we have developed a method to create a hydrangea-like structure of bimetallic cobalt-iron phosphide (B-CoFeP@CoP) through ion-exchange and NaBH4-assisted strategies. This catalyst exhibited excellent bifunctional catalytic capability at high current densities, achieving a current density of 500 mA cm-2 at a small overpotential (387 mV for OER and 252 mV for HER). When assembled into an OWS electrolyzer, this catalyst showed a fairly low cell voltage (≈1.88 V) at 500 mA cm-2 current density., Furthermore, B-CoFeP@CoP shows ceaseless durability over 120 h in both freshwater and seawater with almost no change in the cell voltage. A combined experimental and theoretical study identified that the unique hydrangea-like structure provided a larger electrochemically active surface area and more effective active sites. Further analysis indicates that during the OER process, phosphides ensure that bimetallic active sites adsorb more OOH * intermediates and further DFT calculations showed that B-Fe2P and B-Co2P acted as active centers for dissociation of H2O and desorption of H2, respectively, to synergistically catalyze the HER process.

Photothermal nano-confinement reactor with bimetallic sites for enhanced peroxymonosulfate activation in antibiotic degradation

In recent years, photothermal-assisted Fenton-like degradation of organic pollutants has become a prominent green method in environmental pollution control. Nevertheless, the design of suitable catalysts remains a significant challenge for this approach. Herein, zeolite-imidazolate framework-derived CoMn bimetallic nanoparticles embedded in hollow carbon nanofibers (CoMnHCF) have been developed as a photothermal nano-confinement reactor with multiple active sites to enhance reaction performance and promote peroxymonosulfate (PMS) activation. Under light irradiation, the local temperature within the porous spaces of CoMnHCF was significantly higher than the liquid temperature. The confined space concentrated heat, minimized thermal loss, and effectively utilizes this feature to activate PMS for antibiotic degradation. The results demonstrated that this system efficiently degraded various antibiotics, including tetracycline hydrochloride, levofloxacin, sulfamethoxazole, norfloxacin and chlorotetracycline. Photothermal contribution analysis revealed that thermal effects predominate in this system. Further DFT simulations explored the coordination environment of metal elements and the properties of related pollutants, predicting potential structures and reaction sites. A series of water quality experiments and cyclic tests demonstrated the system's significant application potential. This study offered new insights into advancing the integrated use of photothermal conversion and nano-confinement reactor activation of PMS in sewage purification.

Molten salt electrolytic CO2-derived NiCo2@C catalysts with enhanced oxygen evolution reaction

Carbon-based nonprecious metallic electrocatalysts have garnered considerable attention due to their tunable structures, rapid electron transfer, and easy characterization. There is great anticipation for the development of green and controllable methods for metal-carbon-based electrocatalysts. Molten salts synthesis offers a green, facile and effective approach for fabricating carbon-based materials, utilizing carbon dioxide (CO2) as the carbon source. In this study, the co-electroreduction of CO2 and the binary metal oxide NiCo2O4 is carried out in a mixture of Li2CO3, Na2CO3, and K2CO3 at 500 °C. This process leads to the formation of metal alloy nanoparticles encapsulated in a carbon matrix derived from CO2, referred to as NiCo2@C. The resulting NiCo2@C exhibits low overpotential and Tafel slope (340 mV@10 mA cm−2, 67 mV dec−1) in 0.1 M KOH solution for OER, which is superior to the commercial RuO2 (360 mV@10 mA cm−2, 88 mV dec−1). Both experimental and theoretical findings indicate the synergistic effects of Ni/Co bimetallic sites. Spontaneous adsorption of hydroxide ion on the bridging sites of heterologous diatoms facilitates the adsorption and desorption of intermediates during the OER process.