Low Reaction Barrier Research Articles

In‐Depth Discussion on Electrocatalytic Barrier with Electron Structure of High‐Entropy Alloy Predicted by Transfer Learning and Neural Networks

AbstractAlloy electrodes, beneficial from excellent stability, are considered suitable for industrial applications, hence exploring alloy catalysts with low reaction barriers will bring innovative scientific understanding and enormous economic benefits. Recently, material informatics emerges as an efficient method in the research and development of new materials through diverse candidates, however, collecting a large amount of material characterization and simulation data still faces numerous difficulties. To tackle this issue, combining the topological structure of materials, the convolutional neural network framework developed in this article first achieves the density of states prediction of active sites on the alloy surface, based on which the adsorption energy of different reactants is obtained. Benefited by electronic structure, this model exhibits excellent predictive performance with a mean absolute error of 0.124 eV, and transferability with fast convergence under dozens transferred data to complete the extension for high entropy alloys and reactants. Based on this massive predictive data, high entropy alloy catalysts with excellent low reaction barrier have been discovered, and several catalytic theories, like scaling relations, d‐band center theory, high‐entropy effects and synergistic catalysis, have been validated and improved.

Catalytic Role of Methanol in Anodic Coupling Reactions Involving Alcohol Trapping of Cation Radicals.

In anodic electrosynthesis, cation radicals are often key intermediates that can be highly susceptible to nucleophilic attack and/or deprotonation, with the selectivity of competing pathways dictating product yield. In this work, we computationally investigate the role of methanol in alcohol trapping of enol ether cation radicals for which substantial modulation of the reaction yield by the solvent environment was previously observed. Reaction free energies computed for intramolecular coupling unequivocally demonstrate that the key intramolecular alcohol attack on the oxidized enol ether group is catalyzed by methanol, proceeding through overall second-order kinetics. Methanol complexation with the formed oxonium ion group gives rise to a "Zundel-like", shared proton conformation, providing a critical driving force for the intramolecular alcohol attack. Free energies computed for methanol solvent attack of enol ether cation radicals demonstrate an analogous mechanism and overall third-order kinetics, due to similar complexation from a secondary methanol molecule to form the "Zundel-like", shared proton conformation. As catalyzed by methanol, both intramolecular alcohol attack and methanol attack on the oxidized enol ether group are barrierless or low-barrier reactions, with kinetic competition dictated by the conformational free energy profile of the cation radical substrate and the difference in reaction rate orders.

Single-atomic iron synergistic atom-cluster induce remote enhancement toward oxygen reduction reaction

The oxygen reduction reaction (ORR) could be effectively regulated by adjusting electron configurations and optimizing chemical bonds. Herein, we have achieved the modulation of electron distribution in Fe single atomic (FeSA) sites through Fe atomic clusters (FeAC) via a confined pyrolysis approach, thereby enhancing their intrinsic ORR activity. X-ray absorption spectroscopy has confirmed that the presence of iron atomic clusters could influence the electron distribution at Fe-N4 sites. The FeSA/FeAC-NC catalyst exhibits a half-wave potential of 0.88 V, surpassing the individual FeSA-NC structure. Through electronic structure analysis, it could be seen that iron atom clusters can affect Fe-N4 sites through long-range effects, and then effectively lower reaction barriers and enhance the reaction kinetics at Fe-N4 sites. The synthetic approach might pave the way for constructing highly active catalysts with tunable atomic structures, representing an effective and universal technique for electron modulation in M-N-C systems. This work provides enlightenment for the exploration of more efficient single-atom electrocatalysts and the optimization of the performance of atomic electrocatalysts. Furthermore, a zinc-air battery assembled using it on their cathode deliver a high peak power density (205.7 mW cm−2) and a high-specific capacity of 807.5 mA h g−1. This study offers a fresh approach to effectively enhance the synergistic interaction of between Fe single atom and Fe atomic clusters for improving ORR activity and energy storage.

Theoretical investigation of NH3 nitridation on Cl-terminated Si(100)-2 × 1 surfaces

Enhancing SiN deposition, particularly using NH₃ in atomic layer and chemical vapor deposition, is crucial for improving the performance of Si-based devices. However, while NH₃ nitridation on clean Si surfaces is well understood, its behavior on Cl-terminated Si surfaces remains largely unexplored. In this study, the mechanism of NH3 nitridation on Cl-terminated Si(100)-2 × 1 surfaces is investigated using first-principles calculations and thermodynamic analysis. NH3 reacts with Si–Cl on the surface with low reaction barriers, generating Si–NH2 and gaseous HCl. Subsequently, Si–NH2 forms a Si–NH–Si structure via NH2 insertion into the Si–Si dimer bond and H migration onto the Si-dangling bond. Si–NH–Si formation is more favorable on the Si–Si dimer bond than on the Si–Si back bond. Thermodynamic analyses indicate that NH3 nitridation leads to the Si–NH–Si structure, as Si–NH–Si formation is more thermodynamically stable than Si–NH2 formation. Moreover, it is confirmed that the Si–NH–Si formation reaction is more favorable at higher temperatures and NH3 partial pressures. These findings could potentially be used to improve SiN deposition processes and enhance the performance of Si-based devices.

Tuning structures and catalysis performance of two-dimensional covalent organic frameworks based on copper phthalocyanine building block and phenyl connector

Based on the experimentally reported stable and conductive two-dimensional covalent organic frameworks with copper phthalocyanine (CuPc) as building block and cyan substituted phenyl as connector (CuCOF-CN) as an electrocatalyst for CO2 reduction reaction (RR), first principle calculations were performed on CuCOF-CN and its analog with the CN being replaced by H (CuCOF). Comparatively studied on the crystal structures, electronic properties, and CO2RR performance of the two catalysts found that CuCOF has reduced crystal unit size, more positive charge on Cu and CuPc segments, smaller band gap, and lower reaction barrier for CO2 RR than CuCOF-CN. CuCOF is proposed to be good potential electrocatalyst with good environment friendliness. The substituent effect and structure-property-performance relationship would help for designing and fabricating new electrocatalysts.

Selective hydrogenation of 1,3-butadiene to butenes on ceria-supported Pd, Ni and PdNi catalysts: Combined experimental and DFT outlook

The regulation of catalyst activity and selectivity using a reducible support for the industrially relevant hydrogenation of 1,3-butadiene to more valuable butene products was achieved. Supported palladium and nickel–palladium catalysts on ceria were prepared and characterized with hydrogen temperature programmed reduction (H2-TPR), hydrogen temperature programmed desorption (H2-TPD), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HR-TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), temperature programmed oxidation (TPO), energy dispersive spectroscopy (EDS), and N2 adsorption–desorption to examine their chemical and physical properties. Pathways guiding the reaction were determined using the density functional theory (DFT). H2-TPR confirmed that palladium oxide was reduced, and nickel oxide species strongly interacted with the CeO2 support. The Ce3+ concentration determined by XPS showed that all catalysts surface contained the Ce reduced state. The catalysts showed a similar BET surface area, with 4Pd–Ce presenting the lowest value due to particle aggregation, which was confirmed from the EDS mapping analysis. Butadiene conversion consistently increased with temperature (40 °C–120 °C) until full conversion was reached on all the Pd catalysts while the maximum conversion on the 4Ni-Ce catalyst was 88 % at 120 °C. Product distribution revealed that 4 % Pd content directed the products toward butane when 40 °C was exceeded. Constructed mechanisms by DFT calculations featured low reaction barriers for the involved surface hydrogenation steps, and thus, they accounted for the observed low temperature of the surface hydrogenation activity. Selective formation of 1-butene partially stemmed from its relatively weak binding to Ni sites in reference to Pd sites. The mapped-out mechanisms entailed a higher reaction barrier for the formation of 2-butene, in agreement with the experimental observation pertinent to its formation at higher temperatures when compared with that of 1-butene.

Salt-free neutral dyeing of cotton fiber with monochlorotriazine type reactive dyes

In this paper, we present the modification of cotton with glycidyltrimethylammonium chloride (GTA), demonstrating its capability not only for salt-free dye adsorption but also for achieving fixation reactions with monochlorotriazine-type reactive dyes under neutral conditions. The results of adsorption kinetics and isotherm experiments indicate that the adsorption of reactive dyes by modified cotton is chemisorption. Color-stripping experiments conducted on modified cotton dyed with different dyes revealed that GTA-modified cotton underwent fixation reactions with monochlorotriazine-type reactive dyes under neutral conditions. The reaction sites of modified cotton with reactive dyes were determined by measuring the 1H NMR of the model reaction products. Mechanism investigation using Density Functional Theory (DFT) on the fixation reaction revealed that the hydroxyl groups on the modification agent chain exhibit a lower pKa value and carry more negative charge, resulting in a lower reaction barrier with monochlorotriazine-type reactive dyes. Our research findings demonstrate that GTA-modified cotton fiber enhance the reactivity of cotton, providing significant guidance for the development of novel modifiers.

A Carborane-Derived Proton-Coupled Electron Transfer Reagent.

Reagents capable of concerted proton-electron transfer (CPET) reactions can access reaction pathways with lower reaction barriers compared to stepwise pathways involving electron transfer (ET) and proton transfer (PT). To realize reductive multielectron/proton transformations involving CPET, one approach that has shown recent promise involves coupling a cobaltocene ET site with a protonated arylamine Brønsted acid PT site. This strategy colocalizes the electron/proton in a matter compatible with a CPET step and net reductive electrocatalysis. To probe the generality of such an approach a class of C,C'-diaryl-o-carboranes is herein explored as a conceptual substitute for the cobaltocene subunit, with an arylamine linkage still serving as a colocalized Brønsted base suitable for protonation. The featured o-carborane (PhCbPhN) can be reduced and protonated to generate an N-H bond with a weak effective bond dissociation free energy (BDFEeff) of 31 kcal/mol, estimated with measured thermodynamic data. This N-H bond is among the lowest measured element-H bonds for analyzed nonmetal compounds. Distinct solid-state crystal structures of the one- and two-electron reduced forms of diaryl-o-carboranes are disclosed to gain insight into their well-behaved redox characteristics. The singly reduced, protonated form of the diaryl-o-carborane can mediate multi-ET/PT reductions of azoarenes, diphenylfumarate, and nitrotoluene. In contrast to the aforementioned cobaltocene system, available mechanistic data disclosed herein support these reactions occurring by a rate-limiting ET step and not a CPET step. A relevant hydrogen evolution reaction (HER) reaction was also studied, with data pointing to a PT/ET/PT mechanism, where the reduced carborane core is itself highly stable to protonation.

Unraveling the reaction mechanism of alkali-activated materials through multi-scale modeling

As an environmentally friendly alternative to cement-based materials, alkali-activated materials (AAM) have attracted much attention due to their significant ability to reduce greenhouse gas emissions and effectively utilize industrial waste. Three Si-Al monomers ([SiO2(OH)2]2-, [SiO(OH)3]-, and [Al(OH)4]-) serve as the fundamental building blocks for the formation of AAM gels. Simulating their polycondensation reactions (PR) among these monomers is of paramount importance but faces a delicate balance between precision and efficiency. To unravel the PR mechanisms, we have integrated reactive force field molecular dynamics (MD) simulations with first-principles calculations based on density functional theory. Our 100ps MD simulations reveal that Al monomers exhibit faster reaction rates and lead to the formation of Si-Al oligomers with diverse structures. Subsequent first-principles calculations on transition state models derived from MD results uncover that PR pathways involving Al monomers possess lower energy barriers, which are correlated with changes in chemical bond strength arising from electronic orbital transitions. Our study, for the first time, establishes an intrinsic link among five hierarchical levels: electronic orbital structure, chemical bond strength, reaction energy barrier, reaction rate, and reaction scale. This provides invaluable theoretical guidance for designing energy-efficient and low-barrier reaction pathways for AAM gel formation.

Synergistic enhancement of electro-Fenton redox processes by iron-molybdenum dual sites for synchronous removal of Cr (VI) and emerging organic pollutants

Synergy removal of heavy metals and emerging organic pollutants (EOPs) poses a formidable challenge in heterogeneous electro-Fenton processes. Here, we present a three-dimensional iron-doped molybdenum disulfide hierarchical microsphere/graphite felt (Fe-MoS2 HS/GF) system. This system exhibits exceptional electrocatalytic redox activity, achieving a 9.75-fold and 18.96-fold increase in Cr (VI) (2.38 × 10-2 min−1) and BPA (8.29 × 10-2 min−1) removal rates compared to the MoS2 HS/GF system, respectively. And it also exhibited a significantly enhanced mineralization efficiency (59.28%) for BPA, surpassing that of the MoS2/GF system (5.75%) by a factor of 10.31. Mechanistic insights indicate that the Fe-Mo dual catalytic sites effectively lower reaction barriers of H2O2 dissociation, generating significant amounts of ·OHsurface and 1O2 species for BPA degradation. Moreover, an electric field-driven the variable valence state of the Fe-Mo dual sites facilitates Fe (II) regeneration and Cr (VI) reduction. Notably, this system shows broad applicability for synchronous removal of Cr (VI) and diverse EOPs, exhibiting robust stability under unsteady-state continuous-flow operation (2 L reactor) with reduced biotoxicity in actual wastewater. This study highlights the synergistic benefits of the dual catalytic sites in the heterogeneous electro-Fenton processes for treating multicomponent wastewater.

Understanding the effect of adsorption sites of CO at cobalt surface on its reactivity with H2/H by DFT calculations.

Cobalt (Co) is widely used in Fischer-Tropsch synthesis (FTS), converting synthesis gas, carbon monoxide + hydrogen (CO + H2), to long-chain hydrocarbons. The adsorption of CO on the Co surface is the key step in FTS. In this work, the effect of CO adsorption sites on the reactions between CO and H2 was investigated by using density functional theory (DFT). The energetics and structures of the reactions between the adsorbed CO (CO*) and H2/adsorbed H2 (H2*)/adsorbed H atom (H*) were calculated. The results show that the reaction between CO* and H2 is initiated by the molecular adsorption of H2 on the Co surface. The reactions between CO* and H2*/H* are influenced by CO adsorption sites. For the reaction system of CO* + H2*, it has the lowest reaction barrier when CO is adsorbed at the hcp site, while for CO* + H*, it has the lowest reaction barrier when CO is adsorbed on the top site. Kinetic analysis indicates that to improve the reactivity of CO + H2 in FTS, the adsorption of CO should be controlled to favour the top and bridge sites. This article is part of the theme issue 'Celebrating the 15th anniversary of the Royal Society Newton International Fellowship'.

In-situ synthesis to promote surface reconstruction of metal–organic frameworks for high-performance water/seawater oxidation

Metal-organic frameworks (MOFs) have gained tremendous notice for the application in alkaline water/seawater oxidation due to their tunable structures and abundant accessible metal sites. However, exploring cost-effective oxygen evolution reaction (OER) electrocatalysts with high catalytic activity and excellent stability remains a great challenge. In this work, a promising strategy is proposed to regulate the crystalline structures and electronic properties of NiFe-metal-organic frameworks (NiFe-MOFs) by altering the organic ligands. As a representative sample, NiFe-BDC (BDC: C8H6O4) synthesized on nickel foam (NF) shows extraordinary OER activity in alkaline condition, delivering ultralow overpotentials of 204, 234 and 273 mV at 10, 100, and 300 mA cm−2, respectively, with a small Tafel slope of 21.6 mV dec−1. Only a slight decrease is observed when operating in alkaline seawater. The potential attenuation is barely identified at 200 mA cm−2 over 200 h continuous test, indicating the remarkable stability and corrosion resistance. In-situ measurements indicate that initial Ni2+/Fe2+ goes through oxidation process into Ni3+/Fe3+ during OER, and eventually presents in the form of NiFeOOH/NiFe-BDC heterojunction. The unique self-reconstructed surface is responsible for the low reaction barrier and fast reaction kinetics. This work provides an effective strategy to develop efficient MOF-based electrocatalysts and an insightful view on the dynamic structural evolution during OER.

A robust sandwich structural catalyst of (Cu/CuCo-MOF)2/MXene double heterojunction with outstanding activity toward hydrogen generation

Non-noble metal catalysts have exhibited promising prospects in ammonia borane (NH3BH3) hydrolysis, but their activity and stability still need to be further improved. Herein, a 2D sandwich heterostructural catalyst with Cu/CuCo-MOF and MXene-MOF double heterojunction has been prepared by coupling Ti3C2Tx MXene with bimetal organic framework nanosheets using a facile in situ growth strategy. The optimized CuCo-MOF/MX exhibits unprecedented activity with a turnover frequency (TOF) of 82.3 min–1 and excellent cycle stability, comparable to precious metal catalysts. Spectroscopic characterization and density functional theory (DFT) calculations reveal that Cu/CuCo-MOF heterojunction provides CuCo dual active sites for catalysis, and MXene-MOF heterojunction modulates the electronic structure and valence states of Cu sites via the Ti3C2Tx interlayer with 2D electron promoter effect to improve the synergistic effect of CuCo dual active sites. These modulation optimize the adsorption and dissociation of reactants, leading to a lower reaction barrier. This work provides insight into the 2D electron promoter effect, proposes a novel strategy for improving the performance of non-precious metal catalysts through constructing double heterojunction with 2D electron promoter effect.

Tailoring d–p Orbital Hybridization to Decipher the Essential Effects of Heteroatom Substitution on Redox Kinetics

AbstractThe heteroatom substitution is considered as a promising strategy for boosting the redox kinetics of transition metal compounds in hybrid supercapacitors (HSCs) although the dissimilar metal identification and essential mechanism that dominate the kinetics remain unclear. It is presented that d‐p orbital hybridization between the metal and electrolyte ions can be utilized as a descriptor for understanding the redox kinetics. Herein, a series of Co, Fe and Cu heteroatoms are respectively introduced into Ni3Se4 cathodes, among them, only the moderate Co‐substituted Ni3Se4 can hold the optimal d‐p orbital hybridization resulted from the formed more unoccupied antibonding states π*. It inevitably enhances the interfacial charge transfer and ensures the balanced OH− adsorption‐desorption to accelerate the redox kinetics validated by the lowest reaction barrier (0.59 eV, matching well with the theoretical calculations). Coupling with the lower OH− diffusion energy barrier, the prepared cathode delivers ultrahigh rate capability (~68.7 % capacity retention even the current density increases by 200 times), and an assembled HSC also presents high energy/power density. This work establishes the principles for determining heteroatoms and deciphers the underlying effects of the heteroatom substitution on improving redox kinetics and the rate performance of battery‐type electrodes from a novel perspective of orbital‐scale manipulation.

Tailoring d-p Orbital Hybridization to Decipher the Essential Effects of Heteroatom Substitution on Redox Kinetics.

The heteroatom substitution is considered as a promising strategy for boosting the redox kinetics of transition metal compounds in hybrid supercapacitors (HSCs) although the dissimilar metal identification and essential mechanism that dominate the kinetics remain unclear. It is presented that d-p orbital hybridization between the metal and electrolyte ions can be utilized as a descriptor for understanding the redox kinetics. Herein, a series of Co, Fe and Cu heteroatoms are respectively introduced into Ni3Se4 cathodes, among them, only the moderate Co-substituted Ni3Se4 can hold the optimal d-p orbital hybridization resulted from the formed more unoccupied antibonding states π*. It inevitably enhances the interfacial charge transfer and ensures the balanced OH- adsorption-desorption to accelerate the redox kinetics validated by the lowest reaction barrier (0.59 eV, matching well with the theoretical calculations). Coupling with the lower OH- diffusion energy barrier, the prepared cathode delivers ultrahigh rate capability (~68.7 % capacity retention even the current density increases by 200 times), and an assembled HSC also presents high energy/power density. This work establishes the principles for determining heteroatoms and deciphers the underlying effects of the heteroatom substitution on improving redox kinetics and the rate performance of battery-type electrodes from a novel perspective of orbital-scale manipulation.

Probing σ-Aromaticity-Driven Ring Contraction of Metallabenzocyclobutadiene to Metallabenzocyclopropene.

Ring contraction of metallacyclobutadiene to metallacyclopropene is rare because of the increasing strain from a four-membered ring to a three-membered one. Here we demonstrate a new series of reactions of metallabenzocyclobutadiene to metallabenzocyclopropene via density functional theory calculations. The results suggest that these reactions are thermodynamically favorable ranging from -17.4 to -29.4 kcal mol-1, and a low reaction barrier (10.3 kcal mol-1) is achieved when the metal center is Ru and the ligands are one cyanide and one chloride. Further analysis suggests that a strengthened binding energy helps stabilize the transition state in the protonation process. The aromaticity during the reaction was investigated using the electron density of delocalized bonds (EDDB), isomerization stabilization energy, and isodesmic reactions. The EDDB shows that the π-conjugation is disrupted in the intermediate, and then σ-aromaticity is generated and dominant in the products. Our findings could be helpful for experimentalists in developing novel ring contraction reactions driven by aromaticity.

The role of defects in high-silica zeolite hydrolysis and framework healing

The stability of high silica zeolites under standard laboratory and mild steaming conditions is understood to be due to the lack of hydrophilic Al-O-Si moieties, which can be targeted by water via hydrolysis reactions with relatively low barriers. However, in hydrophobic high-silica and siliceous frameworks, the specific interactions between water and the internal framework sites are incompletely understood. In particular, the behaviour of common internal defects, including partial hydrolysis species and silanol nests are not established, despite their expected role in accelerating the decomposition of the framework. In this work, we utilise machine learning potentials combined with density functional calculations to rigorously sample the hydrolysis processes in siliceous zeolites with topologies CHA and MFI under low water conditions and quantify the effect of defects. Internal silanol defect sites are found to accelerate zeolite decomposition primarily by bypassing the initial, high-barrier hydrolysis step. Subsequent steps proceed with lower reaction barriers. However, all reaction steps are found to be highly activated, and unlikely to occur rapidly at room temperature under conditions of low internal water concentration. Exchange-healing routes, which reverse hydrolysis while incorporating oxygen from water molecules are found to be competitive along the entire hydrolysis pathway in CHA, providing an additional source of stabilization against hydrolytic decomposition.

Insights into bimetallic single-atom-doped g-C3N4 photo-catalysts for CO2 conversion to HCOOH: A DFT study

Developing low-cost, high-efficiency non-noble metallic photocatalytic materials is crucial for CO2 reduction. This paper investigates the substitution of noble metals dopant to a bimetallic non-noble Fe/Co dopant for g-C3N4 to enhance the photocatalytic CO2 reduction performance via density functional theory (DFT) calculations. This study examines the structure, electronic properties, CO2 adsorption configurations, and the transition states and Gibbs free energy of CO2 reduction to HCOOH on noble metal Pt/g-C3N4 doped, single-atom Fe/g-C3N4 doped, and bimetallic Fe/Co doped g-C3N4 catalysts, revealing the mechanisms of catalyst-mediated CO2 reduction. The results demonstrate that the introduction of Fe/Co bimetallic atoms leads to more efficient charge transfer, attributed to the synergistic and electronic effects of the bimetallic coupling, with a charge of 1.264, which is 2.2 and 1.2 times greater than that of Pt and Fe doped g-C3N4, respectively. Furthermore, the stronger adsorption energy of CO2 molecules on Fe/Co/g-C3N4 compared to pure g-C3N4, Pt/g-C3N4, and Fe/g-C3N4 indicates that adsorption on Fe/Co/g-C3N4 is more conducive to CO2 activation. The CO2 reduction reaction (CO2RR) calculations reveal that Fe/Co/g-C3N4 exhibits a lower reaction barrier of 0.789 eV compared to noble metal-doped Pt and single-atom Fe, due to the reduction of the reaction mechanism's energy barrier by the Fe/Co bimetallic doped g-C3N4, which facilitates a more effective reduction of CO2 to HCOOH. As a result, Fe/Co/g-C3N4 emerges as an effective alternative to noble metal-based photocatalysts. This study provides theoretical guidance for the preparation of efficient non-noble metal photocatalysts.

Co─Mn Bimetallic Nanowires by Interfacial Modulation with/without Vacancy Filling as Active and Durable Electrocatalysts for Water Splitting.

Active and stable nonnoble electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are required for water splitting by sustainable electricity. Here, Mn bonded with O and P is incorporated to modulate Co3S4 and Co2P respectively to enhance the catalytic activity and extend the catalyst lifetime. Mn3O4 adjusts the electronic structure of Co3S4 and Co atom fills the oxygen vacancy in Mn3O4. The interfacial interaction endows Co3S4/Mn3O4 to a lower reaction barrier due to ideal binding energies for OER intermediates. Structure stability of active sites and enhanced Co─S bonds by Operando Raman spectroscopy and theoretical calculations reduce the dissolution of Co3S4/Mn3O4, resulting in a lifetime of 500h at 50mAcm-2 for OER. The modulation of Co2P by MnP weakens the interaction between Co sites and adsorbed H*, achieving a high activity under a large current for HER. The assembled electrolyzer affords 50mAcm-2 at 1.58V and exhibits a lifetime of 350h at 50mAcm-2. The calculations disclose the electron interaction for the activity and stability, as well as the enhanced conductivity. The findings develop new avenues toward promoting catalytic activity and stability, making Co─Mn bimetallic nanowires efficient electrocatalysts for nonnoble water electrolyzers.

Degradation of bisphenol F by peroxymonosulfate activated with palladium-based catalysts

In this study, supported Pd catalysts were prepared and used as heterogeneous catalysts for the activation of peroxymonosulfate (PMS) which successfully degrade bisphenol F (BPF). Among the supported catalysts (i.e., Pd/SiO2, Pd/CeO2, Pd/TiO2 and Pd/Al2O3), Pd/TiO2 exhibited the highest catalytic activity due to the high isoelectric point and high Pd0 content. Pd/TiO2 prepared by the deposition method leads to high Pd dispersion, which are the key factors for efficient BPF degradation. The influencing factors were investigated during the reaction process and two possible degradation pathways were proposed. Density functional theory (DFT) calculations demonstrate that stronger BPF adsorption and BPF degradation with lower reaction barrier occurs on smaller Pd particles. The catalytic activities are strongly dependent on the structural features of the catalysts. Both experiments and theoretical calculations prove that the reaction is actuated by electron transfer rather than radicals.