Ultrahigh Activity Research Articles

Ultra-High Activity and Durability of Low-Platinum Fuel Cells Enabled by Encapsulation of L10-PtCo and L12-Pt3Co Intermetallic Compounds.

Developing high-performance, durable, and ultralow-loading platinum (Pt) catalysts for the oxygen reduction reaction (ORR) is crucial for advancing fuel cells. Here, a novel structured alloy catalyst is reported, characterized by Pt-Co intermetallic compounds with a Pt-skin, encapsulated by a covalent organic framework (COF) derived carbon support. This unique structure, combining alloy-induced strain effects and protective encapsulation, leads to exceptional catalytic activity and stability at an ultralow Pt loading of 0.02 mgPt cm-2. To be specific, this catalyst exhibits peak power densities of 1.77W cm-2 in fuel cell tests. It demonstrates a state-of-the-art mass activity of 2.15 A mgPt -1 (@0.9 V), which is 5.38 times that of commercial Pt/C (0.40 A mgPt -1). More importantly, the fuel cell assembled with this novel catalyst displays exceptional durability, with a voltage degradation of only 9.9mV after 100,000 cycles at 0.8 A cm-2 and a mass activity retention of 85% (1.83 A mgPt -1), far exceeding the 2025 initial mass activity (MA) target (0.44 A mgPt -1) of DOE by 4.2 times. Notably, the current density at 0.6 V under hydrogen-air conditions shows only a slight decline after more than 230 h.

Constructing Unsaturated Ru Atom Arrays Confined in Mn Oxides to Boost Neutral Water Reduction.

Recently, Ru single atoms supported on carbon nanomaterials have demonstrated ultrahigh activity for acid hydrogen evolution reaction (HER), however their neutral HER activity remains low due to the sluggish kinetics for both the water dissociation step to generate H* intermediates and subsequent H* recombination in neutral electrolytes. Here, we synthesize ordered low-coordinated Ru atom arrays confined in Mn oxides (i.e., Li4Mn5O12) for concurrently boosting the water dissociation and H* recombination, thus achieving a 6-fold HER activity enhancement than commercial Pt/C in neutral media. Control experiments indicate that low-coordinated Ru atoms with strong affinity to oxygen atoms of water molecules facilitate the water dissociation to rapidly generate H*. More importantly, both electrochemical and theoretic results uncover that the array-like structure allows the activation of two water molecules on two adjacent Ru atoms for enabling direct H*-H* recombination via the Tafel step, while isolated Ru atoms can only activate water one by one for recombining H* via the sluggish Heyrovsky step. Clearly, this work paves new avenues to boosting the electrocatalytic activity by constructing ordered metal atoms assembles with controllable coordination environments.

Constructing Unsaturated Ru Atom Arrays Confined in Mn Oxides to Boost Neutral Water Reduction

Recently, Ru single atoms supported on carbon nanomaterials have demonstrated ultrahigh activity for acid hydrogen evolution reaction (HER), however their neutral HER activity remains low due to the sluggish kinetics for both the water dissociation step to generate H* intermediates and subsequent H* recombination in neutral electrolytes. Here, we synthesize ordered low‐coordinated Ru atom arrays confined in Mn oxides (i.e., Li4Mn5O12) for concurrently boosting the water dissociation and H* recombination, thus achieving a 6‐fold HER activity enhancement than commercial Pt/C in neutral media. Control experiments indicate that low‐coordinated Ru atoms with strong affinity to oxygen atoms of water molecules facilitate the water dissociation to rapidly generate H*. More importantly, both electrochemical and theoretic results uncover that the array‐like structure allows the activation of two water molecules on two adjacent Ru atoms for enabling direct H*–H* recombination via the Tafel step, while isolated Ru atoms can only activate water one by one for recombining H* via the sluggish Heyrovsky step. Clearly, this work paves new avenues to boosting the electrocatalytic activity by constructing ordered metal atoms assembles with controllable coordination environments.

Advancing H-Bonding Organocatalysis for Ring-Opening Polymerization: Intramolecular Activation of Initiator/Chain End.

Organocatalytic ring-opening polymerization (ROP) of lactones is a green method for accessing renewable and biodegradable polyesters. Developing new organocatalysts with high activity and controllability is a major and challenging research topic in this field. Here, we report a series of organocatalysts to achieve a fast and controlled ROP of lactones. These catalysts incorporate (thio)urea and alkoxide in one molecule and act as initiators in the ROP. Such catalysts enable an effective intramolecular activation of initiator/chain end, as revealed by computational studies, resulting in higher activity and fewer (thio)urea loads than existing (thio)urea/alkoxide binary systems. These organocatalysts exhibit ultrahigh activity comparable to metal complexes, i.e., turnover number up to 900 and turnover of frequency up to 4860 min-1, affording polyesters with tailor-made structure, predicted molecular weights, narrow dispersity, less epimerization, and minimal transesterification. The catalyst synthesis is simple and scalable, allowing widely tuned activities of the ROP.

Efficient synthesis of the cyclo-olefin copolymers at high temperature and pressure in a homogeneous mini-tubular reactor

Ethylene-norbornene copolymer (ENC) is one of the most representative cyclo-olefin copolymer (COC). Both the amorphous and semi-crystalline ENCs were efficiently synthesized by the homogeneous solution copolymerization of ethylene (E) and norbornene (NB) using rac-Et(Ind)2ZrCl2/triisobutylaluminium/(Ph3C)B(C6F5)4 ternary catalyst system in a visualized mini-tubular reactor under high temperature (90–130 °C) and given pressure (24 bar). An ultra-high activity of 7.6 × 108 g/(molZr h), as well as considerable efficiency of 14.1 kgENC/gZr was achieved in time of only 30 s at E/NB molar ratio of 3:1. Moreover, a quench-labeling method using 2-thiophenecarbonyl chloride (TPCC) was adopted to calculate the high proportion of active center [C*]/[Zr]. The novel strategy was proposed for preparation of the block semi-crystalline ENC elastomers with excellent tensile performance and high transparency via reversible chain transfer based on spatiotemporal concentration distribution in a mini-tubular reactor.

Acidic water oxidation with ultralow 131 mV overpotential over surface-reconstructed RuIr nanoalloy: Chloride-driven high performance

The oxygen evolution reaction (OER) in kinetics is sluggish but a key electrode reaction for various energy storage and conversion devices, such as green hydrogen from water electrolysis, rechargeable metal-air battery, sustainable carbon dioxide electroreduction, synthetic ammonia, etc. However, it still remains a major and cutting-edge challenge to pioneering catalysts with simultaneously ultrahigh activity and stability for OER, even with diverse performance enhancement strategies, such as complex composition designs, surface chemical reconstructions, and multiphase engineering have been implemented to accelerate this key electrochemical process. Herein, we proposed a chloride-triggered activation and stabilization strategy for the branched RuIr alloy coated by thin IrO2 layer to achieve unparalleled high-performance toward OER in acidic water. The ultralow overpotential of the activated catalyst is reduced to about 131 mV at 10 mA cm−2, with 79-fold enhancement of mass-activity than commercial IrO2. Moreover, a modified proton exchange membrane water electrolysis (PEMWE) device was first constructed by introducing NaCl into recyclable electrolyte. It run a stably and low cell potential (1.514 V) for 170 h, having no obvious performance decay at 50 mA cm−2 in 0.5 M H2SO4 with 1.6 M NaCl, which far exceeding traditional IrO2||Pt/C PEMWE. The outstanding performance stems from that Cl- ions enable a faster lattice oxygen evolution mechanism. The novel catalyst activates asymmetric O-Ir-Cl structure induced by Cl- filled oxygen vacancies, which modify the electronic and geometric properties, improving OER activity. Moreover, these adsorbed ions can also efficiently patch and refill the oxygen vacancies that ensure the long-term structure stability. Therefore, tailoring the chloride-activated Ir-based catalysts with simultaneously improved activity and stability may be a valuable guide to achieve surprisingly high-performances for acidic water splitting.

Atomic-Level Asymmetric Tuning of the Co1-N3P1 Catalyst for Highly Efficient N-Alkylation of Amines with Alcohols.

Despite the extensive development of non-noble metals for the N-alkylation of amines with alcohols, the exploitation of catalysts with high selectivity, activity, and stability still faces challenges. The controllable modification of single-atom sites through asymmetric coordination with a second heteroatom offers new opportunities for enhancing the intrinsic activity of transition metal single-atom catalysts. Here, we prepared the asymmetric N/P hybrid coordination of single-atom Co1-N3P1 by absorbing the Co-P complex on ZIF-8 using a concise impregnation-pyrolysis process. The catalyst exhibits ultrahigh activity and selectivity in the N-alkylation of aniline and benzyl alcohol, achieving a turnover number (TON) value of 3480 and a turnover frequency (TOF) value of 174-h. The TON value is 1 order of magnitude higher than the reported catalysts and even 37-fold higher than that of the homogeneous catalyst CoCl2(PPh3)2. Furthermore, the catalyst maintains its high activity and selectivity even after 6 cycles of usage. Controlling experiments and isotope labeling experiments confirm that in the asymmetric Co1-N3P1 system, the N-alkylation of aniline with benzyl alcohol proceeds via a transfer hydrogenation mechanism involving the monohydride route. Theoretical calculations prove that the superior activity of asymmetric Co1-N3P1 is attributed to the higher d-band energy level of Co sites, which leads to a more stable four-membered ring transition state and a lower reaction energy barrier compared to symmetrical Co1-N4.

Atomic-Level Engineered Cobalt Catalysts for Fenton-Like Reactions: Synergy of Single Atom Metal Sites and Nonmetal-Bonded Functionalities.

Single atom catalysts (SACs) are atomic-level-engineered materials with high intrinsic activity. Catalytic centers of SACs are typically the transition metal (TM)-nonmetal coordination sites, while the functions of coexisting non-TM-bonded functionalities are usually overlooked in catalysis. Herein, the scalable preparation of carbon-supported cobalt-anchored SACs (CoCN) with controlled Co─N sites and free functional N species is reported. The role of metal- and nonmetal-bonded functionalities in the SACs for peroxymonosulfate (PMS)-driven Fenton-like reactions is first systematically studied, revealing their contribution to performance improvement and pathway steering. Experiments and computations demonstrate that the Co─N3C coordination plays a vital role in the formation of a surface-confined PMS* complex to trigger the electron transfer pathway and promote kinetics because of the optimized electronic state of Co centers, while the nonmetal-coordinated graphitic N sites act as preferable pollutant adsorption sites and additional PMS activation sites to accelerate electron transfer. Synergistically, CoCN exhibits ultrahigh activity in PMS activation for p-hydroxybenzoic acid oxidation, achieving complete degradation within 10min with an ultrahigh turnover frequency of 0.38min-1, surpassing most reported materials. These findings offer new insights into the versatile functions of N species in SACs and inspire rational design of high-performance catalysts in complicated heterogeneous systems.

Crystallinity modulation and microenvironment engineering synergistically manipulate ROS generation on Ni single-atom photocatalysts

The microenvironment modulation of metal-based catalysis sites plays a critical role in single-atom photocatalysis, and remains a grand challenge yet. Herein, the single-atom Ni anchored crystalline carbon nitride (Ni/CCN) nanowire arrays are reported. The obtained Ni/CCN nanowire arrays exhibit an impressive photocatalytic activity (>96% degradation of pharmaceuticals and personal care products (PPCPs) in only 5 min) and photocatalytic rate (maximum 0.5941 min−1) with only clean solar energy input. The Ni/CCN catalyst attached on microfiltration membrane in the continuous flow experiments exhibits >90% PPCPs degradation efficiency over 10 h, demonstrating the ultrahigh activity and long-term operation of the Ni/CCN catalysts. The results of electron spin resonance analysis, probe experiment and theoretical calculations demonstrate that the promoted generation of reactive oxygen species (ROS) highly relies on the crystallinity regulation and microenvironment engineering of active metal sites, which are consequently utilized to trigger the rapid degradation of PPCPs. The introduced Ni-N4 moiety disrupts the uniform distribution of delocalized electrons and precisely tunes the electronic distribution of the microenvironment in CCN, providing an electron-rich region coupled with strong electron transfer effect between Ni and adsorbed O, thus optimizing the crucial step for molecular oxygen activation. This work offers a new idea of photocatalysis from theoretical design towards broad applications through the perspective about modulating microenvironment of active metal sites and optimizing intrinsic electronic properties.

Boosted peroxymonosulfate activation by bimetallic organometallic frameworks via by-produced and dominated H2O2 generation

Verifying the role of H2O2 is a critical challenge for deepening the understanding of the mechanism of peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs). In this research, Co, Fe bimetallic organometallic frameworks (ZIF-L@Fe28) were prepared, and their ultrahigh activities via H2O2 generation at Fe and Co sites were experimentally and theoretically verified. The important contribution of H2O2 to 1O2 production was identified through the quantifications of the mutual transformation of active species. Co sites were identified as the most active positions for PMS activation because of they strongly triggered 1O2, SO4·−, ⋅O2−, ·OH, and H2O2. However, the self-quenching of active species suppressed the efficiency and selectivity of 1O2 generation at Co sites. In contrast to Co sites, Fe sites had selective preference for H2O2 generation, and the transformation of H2O2 to 1O2 further enhanced the performance of ZIF-L@Fe28. The supplementary discussion from the perspective of H2O2 will enable the further application of the PMS activation mechanism.

Highly Efficient and Selective Light-Driven Dry Reforming of Methane by a Carbon Exchange Mechanism.

Dry reforming of methane (DRM) is a promising technique for converting greenhouse gases (namely, CH4 and CO2) into syngas. However, traditional thermocatalytic processes require high temperatures and suffer from low selectivity and coke-induced instability. Here, we report high-entropy alloys loaded on SrTiO3 as highly efficient and coke-resistant catalysts for light-driven DRM without a secondary source of heating. This process involves carbon exchange between reactants (i.e., CO2 and CH4) and oxygen exchange between CO2 and the lattice oxygen of supports, during which CO and H2 are gradually produced and released. Such a mechanism deeply suppresses the undesired side reactions such as reverse water-gas shift reaction and methane deep dissociation. Impressively, the optimized CoNiRuRhPd/SrTiO3 catalyst achieves ultrahigh activity (15.6/16.0 mol gmetal-1 h-1 for H2/CO production), long-term stability (∼150 h), and remarkable selectivity (∼0.96). This work opens a new avenue for future energy-efficient industrial applications.

High performance Pt/Nb2W3O14 catalyst for glycerol valorization to 1,3-propanediol

Glycerol hydrogenolysis to 1,3-propanediol (1,3-PDO) is of significance in promoting the biomass valorization. To achieve the efficient conversion, the selective activation of the secondary C–O bonds in the glycerol is vital. In this work, we comparatively investigated the catalytic performances of Pt/Nb2W3O14 catalyst for glycerol hydrogenolysis controlled at the reacting conditions of 140 °C and 40 bar. Compared to Pt/WO3 and Pt/NbOx, the space–time yield (STY) of 1,3-PDO over Pt/Nb2W3O14 catalyst can be improved by a factor of 13, reaching 596.4 mg gcat−1 h−1. The cation ordering of Nb and W on atomic-scale were fully synergized their unique advantages, showing preferential adsorption of the secondary C–O bond under in-situ DRIFTS tracking. The prepared Nb2W3O14 is a tetragonal tungsten bronze (TTB) type complex oxides which can effectively promote the dispersion and reduction of Pt nanoparticles. Such strong interaction between Nb2W3O14 and Pt can coordinate the precise adsorption and activation of the secondary C–O bond, simultaneously triggering subsequent hydrogenation. Pt/Nb2W3O14 affords an ultrahigh activity in glycerol hydrogenolysis to produce 1,3-PDO, tripling the record productivity that was previously reported of these Pt-W based catalysts. This study reported the development of highly synergistic catalyst based on efficient and selective activation of the secondary C–O bond, which can be extended to catalyst design for other biomass valorization.

Feasible preparation of preferentially oriented (111) Pd nanocrystals supported on cyano-COFs for ultrahigh activity in C-C cross-couplings

It is much challenging to synthesize highly dispersed noble metal nanocrystals (MNCs) and prevent their aggregation during the catalytic cycles. Choosing suitable solid supports to mediate the growth of MNCs can provide stable yet ultra-highly active heterogenous catalysts. However, very few studies have provided the controllable preparation of ultrafine MNCs. Herein, cyano-functionalized covalent organic frameworks (cyano-COFs)-mediated ultrafine preferentially oriented (111) PdNCs with particle diameter of 2.88 ± 0.60 nm were easily prepared in MeOH without any other external reducing agent. The obtained Pd/cyano-COFs presented ultrahigh activity in Suzuki-Miyaura couplings, with TOF of 2578 h−1 and chemo-selectivity of > 99 % for the cross-coupling between p-iodotoluene and phenylboronic acid at room temperature in the air. Furthermore, outstanding catalytic performance of Pd/cyano-COFs was found in Heck couplings as well. This study provides a new idea for the controllable preparation of metallic nanomaterials with high performance, which could facilitate the research on the regulation of catalytic performance by the chemical composition of supports.

A Self‐Sustaining Near‐Infrared Afterglow Chemiluminophore for High‐Contrast Activatable Imaging

AbstractAfterglow imaging holds great promise for ultrasensitive bioimaging due to its elimination of autofluorescence. Self‐sustaining afterglow molecules (SAMs), which enable all‐in‐one photon sensitization, chemical defect formation and afterglow generation, possess a simplified, reproducible, and efficient superiority over commonly used multi‐component systems. However, there is a lack of SAMs, particularly those with much brighter near‐infrared (NIR) emission and structural flexibility for building high‐contrast activatable imaging probes. To address these issues, this study for the first time reports a methylene blue derivative‐based self‐sustaining afterglow agent (SAN‐M) with brighter NIR afterglow chemiluminescence peaking at 710 nm. By leveraging the structural flexibility and tunability, an activatable nanoprobe (SAN‐MO) is customized for simultaneously activatable fluoro‐photoacoustic and afterglow imaging of peroxynitrite (ONOO−), notably with a superior activation ratio of 4523 in the afterglow mode, which is at least an order of magnitude higher than other reported activatable afterglow systems. By virtue of the elimination of autofluorescence and ultrahigh activation contrast, SAN‐MO enables early monitoring of the LPS‐induced acute inflammatory response within 30 min upon LPS stimulation and precise image‐guided resection of tiny metastatic tumors, which is unattainable for fluorescence imaging.

A Self-Sustaining Near-Infrared Afterglow Chemiluminophore for High-Contrast Activatable Imaging.

Afterglow imaging holds great promise for ultrasensitive bioimaging due to its elimination of autofluorescence. Self-sustaining afterglow molecules (SAMs), which enable all-in-one photon sensitization, chemical defect formation and afterglow generation, possess a simplified, reproducible, and efficient superiority over commonly used multi-component systems. However, there is a lack of SAMs, particularly those with much brighter near-infrared (NIR) emission and structural flexibility for building high-contrast activatable imaging probes. To address these issues, this study for the first time reports a methylene blue derivative-based self-sustaining afterglow agent (SAN-M) with brighter NIR afterglow chemiluminescence peaking at 710 nm. By leveraging the structural flexibility and tunability, an activatable nanoprobe (SAN-MO) is customized for simultaneously activatable fluoro-photoacoustic and afterglow imaging of peroxynitrite (ONOO- ), notably with a superior activation ratio of 4523 in the afterglow mode, which is at least an order of magnitude higher than other reported activatable afterglow systems. By virtue of the elimination of autofluorescence and ultrahigh activation contrast, SAN-MO enables early monitoring of the LPS-induced acute inflammatory response within 30 min upon LPS stimulation and precise image-guided resection of tiny metastatic tumors, which is unattainable for fluorescence imaging.

The ultra-high oxygen evolution activity of Fe modified NiPt alloy assisted by Pt pre-oxidation in alkaline electrolyte

Constructing ultra-high activity, highly efficient and robust oxygen evolution reaction (OER) electrocatalysts, especially at large current density, plays a key role in the development of the electrolytic water industry but remains challenging. Highly dispersed alloy compound with large electrolyte contact area and excellent internal conductivity is considered as a kind of ideal candidate. Here, we have rationally designed and synthesized a nickel-platinum alloy with octahedral structure loaded on the surface of the carbon layer (NiPt/C). Under the in-situ modulation of the iron-containing electrolyte, the Fe modified NiPt/C catalyst displays an amazing OER activity in 1 M KOH, and only requires low overpotentials of 183 and 242 mV to reach 100 and 1000 mA cm−2, respectively. The comprehensive characterization analysis and property measurements reveal that the pre-oxidation of Pt at OER potential contribute to the rapid production of nickel hydroxide, thus promoting the deposition of more iron active sites on its surface. Moreover, the Pt/C/CP(−)//NiPt/C/CP(+) couple embedded in anion-exchange membrane water electrolyser also displays a low cell voltage of 2.03 V at 1000 mA cm−2 with significant electrochemical stability, which endows it a great potential in the field of hydrogen production and electrochemical energy storage.

Pd-Mn/NC Dual Single-Atomic Sites with Hollow Mesopores for the Highly Efficient Semihydrogenation of Phenylacetylene.

The direct pyrolysis of metal-zeolite imidazolate frameworks (M-ZIFs) has been widely recognized as the predominant approach for synthesizing atomically dispersed metal-nitrogen-carbon single-atom catalysts (M/NC-SACs), which have exhibited exceptional activity and selectivity in the semihydrogenation of acetylene. However, due to weak adsorption of reactants on the single site and restricted molecular diffusion, the semihydrogenation of large organic molecules (e.g., phenylacetylene) was greatly limited for M/NC-SACs. In this work, a dual single-atom catalyst (h-Pd-Mn/NC) with hollow mesopores was designed and prepared using a general host-guest strategy. Taking the semihydrogenation of phenylacetylene as an example, this catalyst exhibited ultrahigh activity and selectivity, which achieved a turnover frequency of 218 molC═CmolPd-1 min-1, 16-fold higher than that of the commercial Lindlar catalyst. The catalyst maintained high activity and selectivity even after 5 cycles of usage. The superior activity of h-Pd-Mn/NC was attributed to the 4.0 nm mesopore interface of the catalyst, which enhanced the diffusion of macromolecular reactants and products. Particularly, the introduction of atomically dispersed Mn with weak electronegativity in h-Pd-Mn/NC could drive the electron transfer from Mn to adjacent Pd sites and regulate the electronic structure of Pd sites. Meanwhile, the strong electronic coupling in Pd-Mn pairs enhanced the d-electron domination near the Fermi level and promoted the adsorption of phenylacetylene and H2 on Pd active sites, thereby reducing the energy barrier for the semihydrogenation of phenylacetylene.

Single-atom catalytic N2 fixation with integrated descriptors on a novel π-π conjugated graphitic carbon nitride (g-C13N15) platform obtained by self-doping design: Prediction of ultrahigh activity and desirable selectivity

Great enthusiasm in nitrogen reduction reaction (NRR) towards the robust design of efficient catalysts is being stimulated by a promising active moiety featured by metal-Nx, yet tackling the activity and selectivity dilemmas remains one of the most urgent and challenging tasks. Herein, based on a self-doping strategy and first-principles calculations, an emerging and stable graphitic carbon nitride, g-C13N15, is rationally proposed for the first time, and TM@g-C13N15 (TM = from Ti to Au) single-atom catalysts benefiting from delocalized π−π conjugated interactions between substituted C3N3 rings toward NRR are constructed. High-throughput “Four-Step” screening strategy helps Re@g-C13N15 stand out from 23 TM-centers quickly since the binding strength of the target *N2H and *NH2 adsorbates can be manipulated by Re to compromise. First-principles calculations reveal that Re@g-C13N15 possesses satisfactory selectivity and impressively, miserly energy consumption with a low limiting potential of −0.20/-0.31 V for side-on/end-on N2-adsorption. Also, good thermodynamic stability, large Re-diffusion barrier, outstanding electrochemical durability, and facile synthesis for Re@g-C13N15 ensure its implementations in ambient conditions. Particularly, good linear relationships between descriptors (ICOHP, Bader charge, bond length, d-band center, and spin moment) are established to describe/explain intrinsic activity trends/mechanism, bridging the relation between the intrinsic property and activity.

Modulating the exposed facets of Pd-Pb intermetallic compounds via morphology engineering for efficient multifunctional electrocatalysts

To develop Pd-based intermetallic compounds (IMCs) nanomaterials with specific morphologies for exposing specific facets is essential yet full of challenges for highly efficient electrocatalysts. Herein, we utilized morphology engineering to successfully acquire Pd-Pb concave nanocubes (Pd-Pb CNCs) with Pd3Pb IMC phase and exposing (200) facet mainly. The Pd-Pb CNCs catalyst displays the ultrahigh activity of 4.01 A mgPd-1 for ethanol oxidation reaction (EOR), surpassing than that of Pd-Pb nanoparticles with Pd3Pb IMC phase but exposing (111) facet mainly, and far exceeding than commercial Pd/C. Density functional theory simulation manifests that the excellent EOR activity for Pd-Pb CNCs is attributed to the weakened reaction intermediates adsorption on catalyst surface. Importantly, the Pd-Pb CNCs are also with excellent reactivities for methanol oxidation reaction and glycerol oxidation reaction, indicating potentials as outstanding multifunctional electrocatalysts. This work may not only furnish a simple strategy for fabricating Pd-based IMCs exposing specific facets, but also promote their high-efficient applications in alcohol oxidation reactions and beyond.

Construction of Rh-N4 single atoms and Rh clusters dual-active sites for synergistic heterogeneous hydroformylation of olefins with ultra-high turnover frequency

The design and construction of Rh-based heterogeneous catalysts with excellent catalytic activity and high atom utilization for hydroformylation of olefins is extremely important but still challenging. Herein, we report a robust dual-active sites coupling catalyst containing triphenyl phosphine-coordinated Rh clusters and Rh-N4 single atomic sites (PPh3-RhAC-SA/N-C) for hydroformylation of olefins. The PPh3-RhAC-SA/N-C exhibits ultra-high activity to the hydroformylation of 1-hexene among the reported Rh-based catalysts, achieving the turnover frequency value of 6599 h−1, which is 13-fold higher than that of conventional Wilkinson’s catalyst (508 h−1). Density functional theory calculations reveal that PPh3-coordinated Rh clusters can facilitate the adsorption and activation of olefins and H2. The adjacent Rh-N4 provides a more favorable adsorption site for CO, enabling the easy addition of CO to carbon chain. The incorporated PPh3 increases the electron cloud density of Rh clusters, reduces the energy barriers of hydrogenation step on Rh clusters, and thereby enhancing the activity of catalyst for hydroformylation. Furthermore, PPh3-RhAC-SA/N-C can be applied as a recyclable catalyst without obvious deactivation. This work provides a novel design concept for the construction of dual sites coupling catalyst from the atomic scale for synergistic heterogeneous hydroformylation.