Surface Active Sites Research Articles

Multidimensional octahedron (de) intercalation cathode for aqueous zinc-ion battery

CuS is a suitable material for use in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Nevertheless, the Zn2+ reaction between CuS is challenging due to the high radius and the considerable electrostatic force between the Zn2+ and CuS cathode. In this work, CuS nanosheets were in situ grown on a template surface via the hydrothermal method. The composition, surface morphology, and microstructure were then studied in detail. The zinc storage properties and mechanism were investigated through electrochemical testing, density functional theory and molecular dynamics simulation. The findings demonstrate that CuS nanosheets are formed in situ along the octahedral surface, resulting in the development of multistage structures. The distinctive configuration is capable of efficaciously preventing nanosheet aggregation, augmenting the specific surface area and active site of electrochemical reactions. Furthermore, the formation of a hollow structure through ion exchange reduces the intercalation energy barrier of Zn2+, facilitates rapid ion diffusion, enhances the charge transfer rate, and markedly improves battery performance.

Efficient transformation of CO2 into α-alkylidene cyclic carbonates over Cu0/Cu+ derived from CuAl layered double hydroxide/reduced graphene oxide hybrid

A simple liquid-phase co-precipitation method was used to achieve a good dispersion of CuAl layered double hydroxide (CuAl-LDH) on the surface of graphene oxide (GO), and Cu2+ in the lattice of CuAl-LDH was in-situ reduced to Cu0 and Cu+ species, resulting in the preparation of R-CuAl-LDH/rGO catalyst. It could effectively catalyze the cyclization of CO2 and propargylic alcohols under mild conditions (50 °C and 1 bar), and the yield exceeded 99 % within only 40 min. Systematic characterization revealed that two-dimensional LDH nanosheets were grown on the rGO surface in an irregular orientation, leading to a higher specific surface area and more abundant surface active sites. Meanwhile, the synergistic catalysis of Cu0 and Cu+ dual-active sites greatly enhanced the catalytic efficiency. In addition, the catalyst had excellent recycling properties with no significant loss of activity after 5 cycles of continuous operation.

Lattice Strain Regulated by Hetero/Homo Atom Interface Merging on NiMo Nanocluster for High-Performance Hydrogen Production.

Lattice strain engineering represents a cutting-edge approach capable of delivering enhanced performance across various applications. The lattice strain can affect the performance of electrochemical catalysts by changing the binding energy between the surface-active sites and intermediates. In this work, lattice strain is regulated through a homo/heterogeneous atomic interface merging. The strong lattice strain and electronic interactions between Ni and Mo facilitated the reaction kinetic of HER. The prepared NiMo@SSM exhibits excellent HER catalytic performance with 70 mV overpotential at the current density of 10 mA cm-2 and long-term stability. The method of controlling lattice strain through hetero/homo atom interface merging provides a new strategy for designing high-performance alkaline HER electrocatalysts.

Giant Charge Separation-Driving Force Together with Ultrafluent Charge Transfer in TiO2/ZnFe-LDH Photoelectrode via Ferroelectric Interface Engineering.

Hydrogen fuel production using photoelectrochemical (PEC) water-splitting technology is incredibly noteworthy as it provides a sustainable and clean method to alleviate the energy environmental crisis. A highly rapid electron shuttle at the semiconductor/WOC (water oxidation cocatalyst) interface is vital to improve the bulk charge transfer and surface reaction kinetics of the photoelectrode in the PEC water-splitting system. Yet, the inevitably inferior interface transition tends to plague the performance enhancement on account of the collision of hole-electron transport across the semi/cat interface. Herein, we address these critical challenges via inserting ferroelectric layer BTO (BaTiO3) into the semi/cat interface. The embedded polarization electric field induced by ferroelectric BTO remarkably pumped hole transfer at the semiconductor/WOC (TiO2/ZnFe-LDH) interface and selectively tailored the electronic structure of LDH surface-active sites, leading to overwhelmingly improved surface hole transfer kinetics at LDH/electrolyte interface, which minish the electron-hole recombination in bulk and on the surface of TiO2. The TiO2 nanorods encapsulated by ferroelectric-assisted ZnFe-LDH achieve 105% charge separation efficiency improvement and 53.8% charge injection efficiency enhancement compared with pure TiO2. This finding offers a strategic design for electrocatalytic-assisted photoelectrode systems by ferroelectric-pumped charge extraction and transfer at the semiconductor/WOC interface.

Bayesian Learning Aided Theoretical Optimization of IrPdPtRhRu High Entropy Alloy Catalysts for the Hydrogen Evolution Reaction.

The complex compositional space of high entropy alloys (HEAs) has shown a great potential to reduce the cost and further increase the catalytic activity for hydrogen evolution reaction (HER) by compositional optimization. Without uncovering the specifics of the HER mechanism on a given HEA surface, it is unfeasible to apply compositional modifications to enhance the performance and save costs. In this work, a combination of density functional theory and Bayesian machine learning is used to demonstrate the unique catalytic mechanism of IrPdPtRhRu HEA catalysts for HER. At high coverage of underpotential-deposited hydrogen, a d-band investigation of the active sites of the HEA surface is conducted to elucidate the superior catalytic performance through electronic interactions between elements. At low coverage, a novel Bayesian learning with oversampling approach is then outlined to optimize the HEA composition for performance improvement and cost reduction. This approach proves more efficacious and efficient and yields higher-quality structures with less training set bias compared with neural-network optimization. The proposed HEA optimization theoretically outperforms benchmark Pt catalysts' overpotential by ≈40% at a 15% reduced synthesis cost comparing to the equiatomic ratio HEA.

Formation mechanism of soot in pyrolysis of 2-methylfuran under high temperature based on ReaxFF molecular dynamics simulation

In this study, the detailed mechanism of soot formation under high temperature pyrolysis of 2-methylfuran (2-MF) has been investigated by using Reactive force field molecular dynamics (ReaxFF MD) simulation. The MD analysis shows that 2-MF undergoes ring cleavage and the removal of CO/HCO/CH2CO/CH3CO, which results in the production of the C2-C4 species, promoting the formation of the initial ring molecules. The clustering of hydrocarbons by radical-chain reaction (CHRCR) mechanism plays a significant role in the mass growth of both polycyclic aromatic hydrocarbons (PAHs) and initial soot particles. The main contributors to this process are C2H2 and resonance-stabilized free radicals of C3 and C4. The H-abstraction-C2H2-addition (HACA) mechanism is important for the formation of surface active sites for PAHs and initial soot to some extent. In addition, the soot formation capacity of 2,5-dimethylfuran (25DMF) and 2-MF are compared. Under the same simulation conditions, 25DMF exhibits a higher capacity to form soot. Compared with 2-MF, 25DMF pyrolysis forms more ring-containing species at the initial stage, particularly cyclopentadiene and its derivatives. These compounds have the ability to promote the formation of PAHs, thus providing further support to the experimental-based theory.

Catalyst Activation of Peroxymonosulfate for Reactive Species Generation and Organic Pollutant Degradation: A Mini Review

This review focuses on the application and mechanisms of peroxymonosulfate (PMS) in advanced oxidation processes (AOPs). It clarifies the significance of PMS in degrading organic pollutants, highlighting its high efficiency in treating persistent contaminants, such as antibiotics. The review details the roles and mechanisms of various catalysts, including single-atom catalysts, metal oxides, non-metal oxides and their composites, as well as metal-organic frameworks (MOFs), in activating PMS. It emphasizes the influence of catalyst surface active sites on both radical and nonradical activation pathways. Key factors affecting PMS activation efficiency, such as PMS concentration, pH value, coexisting ions, and temperature, are examined to underline the importance of optimizing these parameters for effective reaction conditions. By synthesizing existing research, the review not only illustrates the extensive application potential of PMS in AOPs but also identifies future research challenges and directions. This provides a theoretical foundation and technical support for developing efficient, economical, and sustainable water treatment technologies.

Probing Active Sites on Pd/Pt Alloy Nanoparticles by CO Adsorption.

We studied the adsorption of CO on Pd/Pt nanoparticles (NPs) with varying compositions using polarization-dependent Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS) and theoretical calculations (DFT). We prepared PtPd alloy NPs via physical vapor codeposition on α-Al2O3(0001) supports. Our morphological and structural characterization by scanning electron microscopy and grazing incidence X-ray diffraction revealed well-defined, epitaxial NPs. We used CO as a probe molecule to identify the particles' surface active sites. Polarization-dependent FT-IRRAS enabled us to distinguish CO adsorption on top and side facets of the NPs. The role of the Pd/Pt alloy ratio on CO adsorption was investigated by comparing the experimental CO stretching band frequency for different alloy arrangements to the results for pure Pd and Pt NPs. Moreover, we studied the influence of hydrogen adsorption on the NP surface composition. We determined the dependence of the IR bands on the local atomic arrangement via DFT calculations, revealing that both bulk alloy composition and neighboring atoms influence the wavenumber of the bands.

Impact of ultrasonic treatment duration on the microstructure and electrochemical performance of NiZnCo2O4 electrode materials for supercapacitors

This work investigates the impact of different ultrasonic treatment durations on the synthesis and electrochemical performance of NiZnCo2O4 (NZC) supercapacitor electrodes. Optimizing treatment to 20 min resulted in a uniform, compact NiZnCo2O4 layer with improved nanostructures, which increased the surface area and active sites for electrochemical reactions. X-ray diffraction (XRD) confirmed successful NiZnCo2O4 synthesis, revealing distinct crystalline phases of NiO, ZnCo2O4, and Co3O4, with improved crystallinity. Electrochemical tests, conducted using a 1.0 M KOH electrolyte, demonstrated that the NZC-2 electrode treated for 20 min achieved the highest 5.678 F/cm3 volumetric capacitance at 0.5 mA/cm2 current density along with 70.5 Wh/kg an energy density at 260 W/kg power density. The galvanostatic charge-discharge and cyclic voltammetry tests revealed that NZC-2 maintained superior charge-discharge efficiency, showing the longest discharge time at 1 mA/cm². Electrochemical impedance spectroscopy (EIS) measurements demonstrated that NZC-2 exhibited the lowest total impedance, thereby enhancing ion transport efficiency. The NZC-2/AC asymmetric supercapacitor showed excellent long-term stability, retaining 64.2% of its capacity after 20,000 charge-discharge cycles. It successfully powered a 1.2 V small fan, demonstrating its practical applicability. The results highlight the crucial importance of ultrasonic treatment in greatly improving the structural and electrochemical characteristics of NiZnCo2O4 electrodes, which opens up possibilities for the advancement of high-performance supercapacitors.

Very low Ru loadings boosting performance of Ni-based dual-function materials during the integrated CO2 capture and methanation process

Herein, the effect of the Ru:Ni bimetallic composition in dual-function materials (DFMs) for the integrated CO2 capture and methanation process (ICCU-Methanation) is systematically evaluated and combined with a thorough material characterization, as well as a mechanistic (in-situ diffuse reflectance infrared fourier-transform spectroscopy (in-situ DRIFTS)) and computational (computational fluid dynamics (CFD) modelling) investigation, in order to improve the performance of Ni-based DFMs. The bimetallic DFMs are comprised of a main Ni active metallic phase (20 wt%) and are modified with low Ru loadings in the 0.1–1 wt% range (to keep the material cost low), supported on Na2O/Al2O3. It is shown that the addition of even a very low Ru loading (0.1–0.2 wt%) can drastically improve the material reducibility, exposing a significantly higher amount of surface-active metallic sites, with Ru being highly dispersed over the support and the Ni phase, while also forming some small Ru particles. This manifests in a significant enhancement in the CH4 yield and the CH4 production kinetics during ICCU–Methanation (which mainly proceeds via formate intermediates), with 0.2 wt% Ru addition leading to the best results. This bimetallic DFM also shows high stability and a relatively good performance under an oxidizing CO2 capture atmosphere. The formation rate of CH4 during hydrogenation is then further validated via CFD modelling and the developed model is subsequently applied in the prediction of the effect of other parameters, including the H2 inlet concentration, inlet flow rate, dual-function material weight, and reactor internal diameter.

G-C3N4 coupled with GO accelerates carrier separation via high conductivity for photocatalytic MB degradation

Graphitic carbon nitride (g-C3N4) is widely utilized in photocatalysis due to its responsiveness to visible light, low cost, and non-toxicity. However, its efficiency is limited by factors such as the rapid recombination of photogenerated electron-hole pairs, slow electron transfer rates, and a limited number of active surface sites. In this study, g-C3N4 was synthesized through thermal polymerization, and varying amounts of graphene oxide (GO) were incorporated via physical blending to fabricate composite photocatalysts. The results indicated that the incorporation of GO not only increased the specific surface area and modified the pore size distribution of g-C3N4 but also affected the heptazine ring structure through chemical bonding, thereby enhancing the density of active sites. Photocatalytic degradation experiments with methylene blue (MB) indicated that g-C3N4 containing 2% GO exhibited photocatalytic activity 2.84 times greater than that of pristine g-C3N4. Kinetic simulations indicated that the Kapp value for the 2% GO-g-C3N4 composite was 0.00469min-1, which is 4.34 times higher than that of pure g-C3N4 (0.00108min-1). Furthermore, this composite maintained high photocatalytic activity after four cycles of reuse. An analysis of the photocatalytic degradation mechanism revealed that the incorporation of GO effectively promoted the separation and transfer of photogenerated electron-hole pairs, enhanced photocurrent density, and improved carrier separation efficiency. Electron spin resonance (ESR) and free radical scavenging experiments confirmed that the primary active species involved in the degradation of MB by the composite photocatalyst were ·O2- and h+. This study presents a novel approach for enhancing the photocatalytic performance of g-C3N4 by modifying its electronic structure and surface properties.

A Comparative Study on the Electrocatalytic Efficiency of Coupled (CuO-Co3O4) vs. Mixed (CuCo2O4) Metal Oxides: Probed by Hydrazine Oxidation and Sensitive Determination

This work reports the synthesis of copper- and cobalt-based coupled and mixed metal oxides (CuO-Co3O4 and CuCo2O4, respectively) utilizing a simple hydrothermal and calcination approach. CuO-Co3O4, CuCo2O4, and the control samples were characterized by powder X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray, and X-ray photoelectron spectroscopy. TEM and FE-SEM analyses of CuO-Co3O4 reveal the presence of two distinct morphologies: rod- and sphere-shaped particles (CuO and Co3O4, respectively). Further, CuO-Co3O4 was efficiently utilized as an electrocatalyst for the selective oxidation of hydrazine (Hyz). CuO-Co3O4 shows a high redox response compared to CuO, Co3O4, CuCo2O4, and the physical mixture of CuO and Co3O4 (CuO/Co3O4). This enhanced performance is attributed to the synergistic interaction between the metal ions caused by their close proximity and the increased exposure of surface active sites. CuO-Co3O4 shows a broad linear range (1-3500 µM), a low detection limit (0.29 µM), and high sensitivity (0.5756 µA µM-1 cm-2) for the Hyz determination. Kinetic parameters, for instance the diffusion coefficient and catalytic rate constant for Hyz oxidation were obtained using chronoamperometry. Additionally, CuO-Co3O4 was effectively utilized to analyze Hyz in real samples with acceptable recovery rates.

Synergistic effects of CNT-bridged dual-phase MoS2 on MXene as a ternary hybrid electrode for rapid sensing of chloramphenicol in aqueous media

The fabrication of a hybridized electrochemical sensor denoted CNT/MoS2/MXene for chloramphenicol (CAP) detection is described based on growing MoS2 nanoflakes on stacked Ti3C2Tx MXene and bridging the structure obtained with carbon nanotubes (CNTs). Herein, we introduce an acid-etched stacked Ti3C2Tx MXene as an interlayered structure to accommodate solvothermally grown layered MoS2 and a bridged CNT network for the efficient electrocatalytic sensing of CAP. The successful growth of MoS2 on the MXene surface prevented restacking of layered MXene and increased conductivity. Interconnected CNTs over the MoS2 nanoflake array served as an electron transport highway, accelerating the electron transport pathway and maintaining the structural stability of the MXene/MoS2 heterostructure. Morphologically, CNT/MoS2/MXene was found to have a functionalized multilayered structure and to have a greater electron transfer rate, and a larger electrochemically active surface area than the binary feature. Modifying the surface area of MXene with MoS2 and CNTs synergistically enhanced the transportation of kinetic barrier electrons and well-defined the redox cycle in the ferricyanide system. Further, the electrochemical detection of CAP using a CNT/MoS2/MXene electrode by cyclic voltammetry (CV) produced greater electrochemical responses than bare GCE, MXene, CNT-MoS2, and MoS2-MXene. In addition, scanning rates, the effects of different concentrations, and pH electrolyte tests showed that the GCE-CNT/MoS2/MXene electrode was suitable for the electrochemical sensing of CAP. Amperometric response, as determined by i-t profiles, showed the CNT/MoS2/MXene electrode had superior electrochemical sensing performance for CAP detection, a wide linear range (8 to 152 nM), a remarkably low detection limit (0.32 nM), a high sensitivity of 14.22 μA nM−1cm−2, and superior stability (96 % activity retention after four weeks). The synergistic effect of the ternary three-dimensional assembly with CNT bridging over hierarchical MoS2/MXene increased surface-active sites and electron transportation rates and enhanced CAP detection performance. Moreover, the proposed sensor demonstrated high selectivity and satisfactory recovery for milk, eye drops, and pork.

Ambient pressure x-ray photoelectron spectroscopy study on the initial atomic layer deposition process of platinum

The initial adsorption of MeCpPtMe3 is investigated using synchrotron-based ambient pressure x-ray photoelectron spectroscopy (XPS). The experiments are done on a native oxide-covered Si substrate. In addition, a reaction with O2 and the created Pt surface was investigated. Inspiration for the reaction studies was found from atomic layer deposition of metallic Pt, process that uses the same compounds as precursors. With time-resolved XPS, we have been able to observe details of the deposition process and especially see chemical changes on the Pt atoms during the initial deposition of the Pt precursor. The change of the binding energy of the Pt 4f core level appears to occur on a different timescale than the growth of the active surface sites. The very long pulse of the Pt precursor resulted in a metallic surface already from the beginning, which suggest chemical vapor deposition-like reactions occurring between the surface and the precursor molecules in this experiment. Additionally, based on the XPS data measured after the Pt precursor pulse, we can make suggestions for the reaction pathway, which point toward a scenario that leaves carbon from the MeCpPtMe3 precursor on the surface. These carbon species are then efficiently removed by the subsequent coreactant pulse, leaving behind a mostly metallic Pt film.

Ternary g-C3N4/Co3O4/CeO2 nanostructured composites for electrochemical energy storage supercapacitors

Extensive use of fossil fuels causes heavy discharge of carbon dioxide, depleting energy resources and this requires environmentally friendly and effective energy storage materials. Hybrid supercapacitors (HSCs) are recently developed as effective energy storage materials enabling high capacitance retention rate and quick charging. Herein, synthesis of two-dimensional g-C3N4 nanosheets supported onto three-dimensional flower-like Co3O4/CeO2 (CoCe) ternary synergistic heterostructures are developed as effective electrodes for hybrid supercapacitor applications. Addition of g-C3N4 produces substantial surface active sites, enabling its synergistic effect with CoCe to enhance electrochemical performance having exceptional conductivity. The CoCe/g-C3N4 ternary composite electrode exhibits a higher specific capacitance of 1088.3 F g−1 at 1 A g-1 with 96 % of recycling stability over 5000 cycles, which is ∼5.5 and ∼5 folds higher specific capacitance than the pristine g-C3N4 and CoCe electrodes. EIS analysis revealed that CoCe/g-C3N4 electrode offered reduced charge transfer resistance compared to pristine electrodes. The fabricated two-electrode HSC device displays outstanding retention after 10,000 cycles with an ultra-high specific capacitance of 119.8 F g−1, excellent energy density 37.4 Wh kg−1 and power density of 749.9 W kg−1. This research showcases the perspectives of CoCe/g-C3N4 ternary electrodes in hybrid supercapacitors and other renewable energy storage devices.

Highly Efficient NO Conversion on Layered Photocatalysts: Surface Active Site Regulation and Molecule Activation

Highly Efficient NO Conversion on Layered Photocatalysts: Surface Active Site Regulation and Molecule Activation

Unraveling the roles of atomically-dispersed Au in boosting photocatalytic CO2 reduction and aryl alcohol oxidation

Atomically-dispersed metal-based materials represent an emerging class of photocatalysts attributed to their high catalytic activity, abundant surface active sites, and efficient charge separation. Nevertheless, the roles of different forms of atomically-dispersed metals (i.e., single-atoms and atomic clusters) in photocatalytic reactions remain ambiguous. Herein, we developed an ethylenediamine (EDA)-assisted reduction method to controllably synthesize atomically dispersed Au in the forms of Au single atoms (AuSA), Au clusters (AuC), and a mixed-phase of AuSA and AuC (AuSA+C) on CdS. In addition, we elucidate the synergistic effect of AuSA and AuC in enhancing the photocatalytic performance of CdS substrates for simultaneous CO2 reduction and aryl alcohol oxidation. Specifically, AuSA can effectively lower the energy barrier for the CO2→*COOH conversion, while AuC can enhance the adsorption of alcohols and reduce the energy barrier for dehydrogenation. As a result, the AuSA and AuC co-loaded CdS show impressive overall photocatalytic CO2 conversion performance, achieving remarkable CO and BAD production rates of 4.43 and 4.71 mmol g−1 h−1, with the selectivities of 93% and 99%, respectively. More importantly, the solar-to-chemical conversion efficiency of AuSA+C/CdS reaches 0.57%, which is over fivefold higher than the typical solar-to-biomass conversion efficiency found in nature (ca. 0.1%). This study comprehensively describes the roles of different forms of atomically-dispersed metals and their synergistic effects in photocatalytic reactions, which is anticipated to pave a new avenue in energy and environmental applications.

Efficient fluoride recovery from wastewater using mesoporous Ca-based nanomaterials derived from municipal solid waste incineration fly ash via fluidized bed crystallization

This study introduces an innovative approach utilizing mesoporous Ca-based nanomaterial (MCN) derived from municipal solid waste incineration (MSWI) fly ash as carriers in a fluidized bed crystallization (FBC) process for the recovery of fluoride from semiconductor wastewater. The transformation of nonporous MSWI fly ash into mesoporous structures was achieved through facile treatments, including ultrasonic-assisted leaching with ethylenediaminetetraacetic acid disodium salt dihydrate (EDTA–Na) and surface modification with sodium silicate, enhancing surface functionalities and active site formation. The resulting MCN exhibited a significant surface area of 222.0 m2/g, ideal for fluoride recovery. When tested with synthetic wastewater, the recovery efficiency and crystallization ratio of fluoride using MCN in the FBC system reached 99.0 % and 93.3 %, respectively. Further investigation revealed that the unique surface properties and large surface area of the MCN promoted the crystallization of fluoride-containing precipitates, resulting in homogeneously nucleated cubic CaF2 crystals and facilitating layer-by-layer crystal growth. Testing the FBC process with real semiconductor wastewater resulted in a crystallization efficiency of 94.5 %, with the CaF2 content in the recovered precipitates reaching 84.3±0.7 %. These findings highlight the potential of MCN as an innovative carrier for fluoride recovery, demonstrating a novel and environmentally friendly method for converting waste into valuable materials. This study offers a promising solution for treating fluoride-contaminated wastewater, with high potential to revolutionize industrial wastewater management and promote a circular economy.

Interface Engineering Induced by Low Ru Doping in Ni/Co@NC Derived from Ni-ZIF-67 for Enhanced Electrocatalytic Overall Water Splitting.

Electrochemical water splitting is a promising approach for hydrogen evolution reactions (HER); however, the oxygen evolution reaction (OER) remains a major bottleneck due to its high energy requirements. High-performance electrocatalysts capable of facilitating HER, OER, and overall water splitting (OWS) are highly needed to improve OER kinetics. In this work, we synthesized a trimetallic heterostructure of Ru, Ni, and Co incorporated into N-doped carbon (denoted as Ru/Ni/Co@NC) by first synthesizing Ni/Co@NC from Ni-ZIF-67 polyhedrons via high-temperature carbonization, followed by Ru doping using the galvanic replacement method. Benefiting from increased active surface sites, modulated electronic structure, and enhanced interfacial synergistic effects, Ru/Ni/Co@NC exhibited exceptional electrocatalytic performance for both HER and OER processes. The optimized Ru/Ni/Co@NC catalyst, with a minimal Ru mass ratio of ∼2.07%, demonstrated significantly low overpotential values of 34 mV for HER and 174 mV for OER at a current density of 10 mA/cm2 with corresponding Tafel slope values of 33.42 and 34.39 mV/dec, respectively. Further, the optimized catalyst was loaded onto carbon paper and used as anode and cathode materials for alkaline water splitting. Interestingly, a low cell voltage of just 1.44 V was obtained. The enhanced electrolytic performance was further elaborated by density functional theory (DFT) calculations, which confirmed that Ru doping in Ni/Co introduced additional active sites for H*, enhancing adsorption/desorption abilities for HER (ΔGH* = -0.30 eV), lowering water dissociation barrier (ΔGb = 0.49 eV) and reducing the energy barrier for the rate-determining step of OER (O* → OOH*) to 1.62 eV in an alkaline environment. These findings reflect the significant potential of ZIF-67-based catalysts in energy conversion and storage applications.

MIL-125-PDI/ZnIn2S4 Inorganic-Organic S-Scheme Heterojunction With Hierarchical Hollow Nanodisc Structure for Efficient Hydrogen Evolution from Antibiotic Wastewater Remediation.

Efficient photocatalytic production of H2 from wastewater is expected to address environmental pollution and energy crises effectively. However, the rapid recombination of photoinduced carriers results in low photoconversion efficiency. At present, inorganic-organic S-scheme heterojunction have become a prominent and promising technology. In this study, an organic ligand modified MIL-125-PDI/ZnIn2S4 (ZIS) inorganic-organic S-scheme heterojunction catalyst is designed. ZIS nanosheets are grown on the disc-shaped MIL-125-PDI surface to form a distinctive hollow nanodiscs with hierarchical structure, giving the material an abundance of surface active sites, an optimized electronic structure, and a spatially separated redox surface. Consequently, the optimal 100MIL-125-PDI250/ZIS exhibited high photocatalytic HER of 508.99 µmol g-1 h-1 in Tetracycline hydrochloride (TC-HCl) solution. Meanwhile, the catalyst achieved complete TC-HCl removal and mineralization rate of 66.62% in 4h. Experimental and theoretical calculations corroborate that the staggered band alignment and work function difference between MIL-125-PDI and ZIS induce the formation of a built-in electric field, thus regulating the charge transfer routes and consequently enhancing charge separation efficiency. The possible photocatalytic mechanism is analyzed using liquid chromatography-mass spectrometry (LC-MS), and the toxicities of the degradation products are also evaluated. This work presents a green dual-function strategy for H2 production and antibiotic wastewater recycling.