Atomic Manipulation to Create High-Valent Fe4+ for Efficient and Ultrastable Oxygen Evolution at Industrial-Level Current Density.

Manipulating the electronic structure of a catalyst at the atomic level is an effective but challenging way to improve the catalytic performance. Here, by stretching the Fe-O bond in FeOOH with an inserted Mo atom, a Fe-O-Mo unit can be created, which will induce the formation of high-valent Fe4+ during the alkaline oxygen evolution reaction (OER). The highly active Fe4+ state has been clearly revealed by in situ X-ray absorption spectroscopy, which can both enhance the oxidation capability and lead to an efficient and stable adsorbate evolution mechanism (AEM) pathway for the OER. As a result, the obtained Fe-Mo-Ni3S2 catalyst exhibits both superior OER activity and outstanding stability, which can achieve an industrial-level current density of 1 A cm-2 at a low overpotential of 259 mV (at 60 °C) and can stably work at the large current for more than 2000 h. Moreover, by coupling with commercial Pt/C, the Fe-Mo-Ni3S2∥Pt/C system can be used in the anion exchange membrane cell to acquire 1 A cm-2 for overall water splitting at 1.68 V (2.03 V for 4 A cm-2), outperforming the benchmark RuO2∥Pt/C system. The efficient, low-cost, and ultrastable OER catalyst enabled by manipulating the atomic structure may provide potential opportunities for future practical water splitting.

Novel Gel method MXene-Supported Dual-Site PtNi-NiO for Electrocatalytic Water Reduction and Urea Oxidation.

Compared to the traditional oxygen evolution reaction (OER), the urea oxidation reaction (UOR) generally exhibits a lower overpotential during the electrolytic process, which is conducive to the hydrogen evolution reaction (HER) at the cathode. The superior structure and abundant sites play a crucial role in promoting the adsorption and cleavage of urea molecules. Therefore, this paper introduces a simple metal cation-induced gelation method to prepare an electrocatalyst with PtNi alloy-NiO dual sites supported on Ti3C2Tx, which simultaneously exhibits excellent UOR and HER performance. PtNi-NiOx/Ti3C2Tx demonstrates good catalytic activity for the urea oxidation reaction, requiring only 1.364 V (overpotential of 0.994 V) to achieve a current density of 100 mA cm-2 in UOR, and also exhibits remarkable catalytic activity in the hydrogen evolution reaction, with PtNi-NiOx/Ti3C2Tx achieving a current density of 10 mA cm-2 in HER with only 24 mV of overpotential. In the UOR//HER two-electrode electrolysis cell, it requires only 1.361 and 1.538 V to reach current densities of 10 and 100 mA cm-2, respectively. According to density functional theory (DFT) calculations, the dual active sites can intelligently adsorb the electron-donating/electron-withdrawing groups in urea molecules, activate chemical bonds, and thereby initiate urea decomposition.

Perfluoroalkyl-modified covalent organic frameworks for continuous photocatalytic hydrogen peroxide synthesis and extraction in a biphasic fluid system.

H2O2 photosynthesis represents an appealing approach for sustainable and decentralized H2O2 production. Unfortunately, current reactions are mostly carried out in laboratory-scale single-phase batch reactors, which have a limited H2O2 production rate (<100 µmol h-1) and cannot operate in an uninterrupted manner. Herein, we propose continuous H2O2 photosynthesis and extraction in a biphasic fluid system. A superhydrophobic covalent organic framework photocatalyst with perfluoroalkyl functionalization is rationally designed and prepared via the Schiff-base reaction. When applied in a home-built biphasic fluid photo-reactor, the superhydrophobicity of our photocatalyst allows its selective dispersion in the oil phase, while formed H2O2 is spontaneously extracted to the water phase. Through optimizing reaction parameters, we achieve continuous H2O2 photosynthesis and extraction with an unprecedented production rate of up to 968 µmol h-1 and tunable H2O2 concentrations from 2.2 to 38.1 mM. As-obtained H2O2 solution could satisfactorily meet the general demands of household disinfection and wastewater treatments.

High-efficiency C3 electrosynthesis on a lattice-strain-stabilized nitrogen-doped Cu surface.

The synthesis of multi-carbon (C2+) fuels via electrocatalytic reduction of CO, H2O using renewable electricity, represents a significant stride in sustainable energy storage and carbon recycling. The foremost challenge in this field is the production of extended-chain carbon compounds (Cn, n ≥ 3), wherein elevated *CO coverage (θco) and its subsequent multiple-step coupling are both critical. Notwithstanding, there exists a "seesaw" dynamic between intensifying *CO adsorption to augment θco and surmounting the C-C coupling barrier, which have not been simultaneously realized within a singular catalyst yet. Here, we introduce a facilely synthesized lattice-strain-stabilized nitrogen-doped Cu (LSN-Cu) with abundant defect sites and robust nitrogen integration. The low-coordination sites enhance θco and concurrently, the compressive strain substantially fortifies nitrogen dopants on the catalyst surface, promoting C-C coupling activity. The n-propanol formation on the LSN-Cu electrode exhibits a 54% faradaic efficiency and a 29% half-cell energy efficiency. Moreover, within a membrane electrode assembly setup, a stable n-propanol electrosynthesis over 180 h at a total current density of 300 mA cm-2 is obtained.

Discovery of highly efficient dual-atom catalysts for propane dehydrogenation assisted by machine learning.

Propane dehydrogenation (PDH) is a highly efficient approach for industrial production of propylene, and the dual-atom catalysts (DACs) provide new pathways in advancing atomic catalysis for PDH with dual active sites. In this work, we have developed an efficient strategy to identify promising DACs for PDH reaction by combining high-throughput density functional theory (DFT) calculations and the machine-learning (ML) technique. By choosing the γ-Al2O3(100) surface as the substrate to anchor dual metal atoms, 435 kinds of DACs have been considered to evaluate their PDH catalytic activity. Four ML algorithms are employed to predict the PDH activity and determine the relationship between the intrinsic characteristics of DACs and the catalytic activity. The promising catalysts of CuFe, CuCo and CoZn DACs are finally screened out, which are further validated by the whole kinetic reaction calculations, and the highly efficient performance of DACs is attributed to the synergistic effects and interactions between the paired active sites.

A metastable pentagonal 2D material synthesized by symmetry-driven epitaxy.

Most two-dimensional (2D) materials experimentally studied so far have hexagons as their building blocks. Only a few exceptions, such as PdSe2, are lower in energy in pentagonal phases and exhibit pentagons as building blocks. Although theory has predicted a large number of pentagonal 2D materials, many of these are metastable and their experimental realization is difficult. Here we report the successful synthesis of a metastable pentagonal 2D material, monolayer pentagonal PdTe2, by symmetry-driven epitaxy. Scanning tunnelling microscopy and complementary spectroscopy measurements are used to characterize this material, which demonstrates well-ordered low-symmetry atomic arrangements and is stabilized by lattice matching with the underlying Pd(100) substrate. Theoretical calculations, along with angle-resolved photoemission spectroscopy, reveal monolayer pentagonal PdTe2 to be a semiconductor with an indirect bandgap of 1.05 eV. Our work opens an avenue for the synthesis of pentagon-based 2D materials and gives opportunities to explore their applications such as multifunctional nanoelectronics.

Engineering Partially Oxidized Gold via Oleylamine Modifier as a High-Performance Anode Catalyst in a Direct Borohydride Fuel Cell.

Direct borohydride fuel cell (DBFC) is considered a promising energy storage device due to its high theoretical cell voltage and energy density. For DBFC, an Au catalyst has been used as an anode for achieving an ideal eight-electron reaction. However, the poor activity of the Au catalyst for borohydride oxidation reaction (BOR) limits its large-scale application because of the weak BH4- adsorption. We found, by density functional theory calculations, that the adsorption of BH4- on the oxidized Au surface is stronger than that on the metallic Au surface, which can promote the process of the oxidation of BH4- to *BH3 during the BOR. Here, we reported an oleylamine-modified partially oxidized Au supported on carbon powder (AuC-OLA) with a stable oxidation state. The obtained catalyst delivered a high peak power density of 143 mW/cm2, which is 2 times higher than that of a commercial 40% AuC (Pretemek). The in situ Fourier transform infrared studies showed that the activity of AuC-OLA for BOR is ascribed to the enhanced adsorption for BH4- on the partially oxidized Au surface. These findings will promote the reasonable design of efficient Au electrocatalysts for DBFCs.

Strain-Triggered Distinct Oxygen Evolution Reaction Pathway in Two-Dimensional Metastable Phase IrO2 via CeO2 Loading.

A strain engineering strategy is crucial for designing a high-performance catalyst. However, how to control the strain in metastable phase two-dimensional (2D) materials is technically challenging due to their nanoscale sizes. Here, we report that cerium dioxide (CeO2) is an ideal loading material for tuning the in-plane strain in 2D metastable 1T-phase IrO2 (1T-IrO2) via an in situ growth method. Surprisingly, 5% CeO2 loaded 1T-IrO2 with 8% compressive strain achieves an overpotential of 194 mV at 10 mA cm-2 in a three-electrode system. It also retained a high current density of 900 mA cm-2 at a cell voltage of 1.8 V for a 400 h stability test in the proton-exchange membrane device. More importantly, the Fourier transform infrared measurements and density functional theory calculation reveal that the CeO2 induced strained 1T-IrO2 directly undergo the *O-*O radical coupling mechanism for O2 generation, totally different from the traditional adsorbate evolution mechanism in pure 1T-IrO2. These findings illustrate the important role of strain engineering in paving up an optimal catalytic pathway in order to achieve robust electrochemical performance.

Patterned graphene: An effective platform for adsorption, immobilization, and destruction of SARS-CoV-2 Mpro.

To address the ongoing challenges posed by the SARS-CoV-2 and potentially stronger viruses in the future, the development of effective methods to fabricate patterned graphene (PG) and other precisely functional products has become a new research frontier. Herein, we modeled the "checkerboard" graphene (CG) and stripped graphene (SG) as representatives of PG, and studied their interaction mechanism with the target protein (Mpro) by molecular dynamics simulation. The calculation results on the binding strength and the root mean square deviation values of the active pocket revealed that PG is an effective platform for adsorption, immobilization, and destruction of Mpro. Specifically, CG is found to promote disruption of the active pocket for Mpro, but the presence of "checkerboard" oxidized regions inhibits the adsorption of Mpro. Meanwhile, the SG can effectively confine Mpro within the non-oxidized strips and enhances their binding strength, but doesn't play well on disrupting the active pocket. Our work not only elucidates the biological effects of PGs, but also provides guidance for their targeted and precise utilization in combating the SARS-CoV-2.

Regioselective epitaxial growth of metallic heterostructures.

Constructing regioselective architectures in heterostructures is important for many applications; however, the targeted design of regioselective architectures is challenging due to the sophisticated processes, impurity pollution and an unclear growth mechanism. Here we successfully realized a one-pot kinetically controlled synthetic framework for constructing regioselective architectures in metallic heterostructures. The key objective was to simultaneously consider the reduction rates of metal precursors and the lattice matching relationship at heterogeneous interfaces. More importantly, this synthetic method also provided phase- and morphology-independent behaviours as foundations for choosing substrate materials, including phase regulation from Pd20Sb7 hexagonal nanoplates (HPs) to Pd8Sb3 HPs, and morphology regulation from Pd20Sb7 HPs to Pd20Sb7 rhombohedra and Pd20Sb7 nanoparticles. Consequently, the activity of regioselective epitaxially grown Pt on Pd20Sb7 HPs was greatly enhanced towards the ethanol oxidation reaction; its activity was 57 times greater than that of commercial Pt/C, and the catalyst showed increased stability (decreasing by 16.3% after 2,000 cycles) and selectivity (72.4%) compared with those of commercial Pt/C (56.0%, 18.2%). This work paves the way for the design of unconventional well-defined heterostructures for use in various applications.

Heterostructured Pt-PbS Nanobelt Achieves Remarkable Direct Formic Acid Oxidation Catalysis.

Developing efficient and CO-tolerant platinum (Pt)-based anodic catalysts is challenging for a direct formic acid fuel cell (DFAFC). Herein, we report heterostructured Pt-lead-sulfur (PtPbS)-based nanomaterials with gradual phase regulation as efficient formic acid oxidation reaction (FAOR) catalysts. The optimized Pt-PbS nanobelts (Pt-PbS NBs/C) display the mass and specific activities of 5.90 A mgPt-1 and 21.4 mA cm-2, 2.2/1.2, 1.5/1.1, and 36.9/79.3 times greater than those of PtPb-PbS NBs/C, Pt-PbSO4 NBs/C, and commercial Pt/C, respectively. Simultaneously, it exhibits a higher membrane electrode assembly (MEA) power density (183.5 mW cm-2) than commercial Pt/C (40.3 mW cm-2). This MEA stably operates at 0.4 V for 25 h, demonstrating a competitive potential of device application. The distinctive heterostructure endows the Pt-PbS NBs/C with optimized dehydrogenation steps and resisting the CO poisoning, thus presenting the remarkable FAOR performance. This work paves an effective avenue for creating high-performance anodic catalysts for fuel cells and beyond.

Strain-induced catalytic enhancement in Co-BTA and Rh-BTA for efficient 2e- oxygen reduction: a DFT study.

Here we design TM-BTA catalysts for the electrochemical synthesis of hydrogen peroxide (H2O2), focusing on the efficient two-electron (2e-) oxygen reduction pathway. Employing density functional theory (DFT), we screened 17 transition metals, identifying Co-BTA and Rh-BTA as outstanding candidates based on their low overpotentials and superior catalytic activity. A key innovation is the application of mechanical strain to these catalysts, significantly optimizing their performance by modulating the d-band center. This approach enhances the adsorption of oxygen-containing intermediates, crucial for the 2e- ORR process. Our findings demonstrate that a tensile strain of 1.95% optimally enhances catalytic efficiency in both Co-BTA and Rh-BTA, substantially reducing overpotential. This research not only highlights the potential of TM-BTA catalysts in H2O2 production but also underscores the importance of strain modulation as a cost-effective and efficient method to improve the selectivity and activity of electrocatalysts, offering a novel perspective in the field of sustainable chemical synthesis.

An all-metallic nanovesicle for hydrogen oxidation.

Vesicle, a microscopic unit that encloses a volume with an ultrathin wall, is ubiquitous in biomaterials. However, it remains a huge challenge to create its inorganic metal-based artificial counterparts. Here, inspired by the formation of biological vesicles, we proposed a novel biomimetic strategy of curling the ultrathin nanosheets into nanovesicles, which was driven by the interfacial strain. Trapped by the interfacial strain between the initially formed substrate Rh layer and subsequently formed RhRu overlayer, the nanosheet begins to deform in order to release a certain amount of strain. Density functional theory (DFT) calculations reveal that the Ru atoms make the curling of nanosheets more favorable in thermodynamics applications. Owing to the unique vesicular structure, the RhRu nanovesicles/C displays excellent hydrogen oxidation reaction (HOR) activity and stability, which has been proven by both experiments and DFT calculations. Specifically, the HOR mass activity of RhRu nanovesicles/C are 7.52 A mg(Rh+Ru)-1 at an overpotential of 50 mV at the rotating disk electrode (RDE) level; this is 24.19 times that of commercial Pt/C (0.31 mA mgPt-1). Moreover, the hydroxide exchange membrane fuel cell (HEMFC) with RhRu nanovesicles/C displays a peak power density of 1.62 W cm-2 in the H2-O2 condition, much better than that of commercial Pt/C (1.18 W cm-2). This work creates a new biomimetic strategy to synthesize inorganic nanomaterials, paving a pathway for designing catalytic reactors.

Chromium-Induced High Covalent Co-O Bonds for Efficient Anodic Catalysts in PEM Electrolyzer.

The proton exchange membrane water electrolyzer (PEMWE), crucial for green hydrogen production, is challenged by the scarcity and high cost of iridium-based materials. Cobalt oxides, as ideal electrocatalysts for oxygen evolution reaction (OER), have not been extensively applied in PEMWE, due to extremely high voltage and poor stability at large current density, caused by complicated structural variations of cobalt compounds during the OER process. Thus, the authors sought to introduce chromium into a cobalt spinel (Co3O4) catalyst to regulate the electronic structure of cobalt, exhibiting a higher oxidation state and increased Co-O covalency with a stable structure. In-depth operando characterizations and theoretical calculations revealed that the activated Co-O covalency and adaptable redox behavior are crucial for facilitating its OER activity. Both turnover frequency and mass activity of Cr-doped Co3O4 (CoCr) at 1.67 V (vs RHE) increased by over eight times than those of as-synthesized Co3O4. The obtained CoCr catalyst achieved 1500 mA cm-2 at 2.17 V and exhibited notable durability over extended operation periods - over 100 h at 500 mA cm-2 and 500 h at 100 mA cm-2, demonstrating promising application in the PEMWE industry.

Enantioselective and Band-Gap Modulation in Photocatalysis of Metal-Free Chiral Carbon Dots.

Photodriven chiral catalysis is the combination of photocatalysis and chiral catalysis and is considered one of the cleanest and most efficient methods for the synthesis of chiral compounds or drugs. Furthermore, due to the potential metal contamination associated with most metal-based catalysts, metal-free chiral photocatalysts are ideal candidates. In this work, we demonstrate that metal-free chiral carbon dots (CDs) exhibit size-dependent enantioselective photocatalytic activity. Using serine as the raw material, chiral CDs with well-defined structures and average sizes of 2.22, 3.01, 3.70, 4.77, and 7.21 nm were synthesized using the electrochemical method. These chiral CDs possess size-dependent band gaps and exhibit photoresponsive enantioselective catalytic activity toward the oxidation of dihydroxyphenylalanine (DOPA). Under light-assisted conditions, chiral CDs (L72, 500 µg/mL) exhibit high selectivity (selectivity factor: 2.07) and maintain a certain level of catalytic activity (1.34 µM/min) even at a low temperature of 5 °C. The high catalytic activity of the chiral CDs arises from their photoelectrons reducing O2 to generate O2-, as the active oxygen species for DOPA oxidation. The high enantioselectivity of the chiral CDs is attributed to their differential adsorption capabilities toward DOPA enantiomers. This study provides a new approach for designing metal-free chiral photocatalysts with high enantioselectivity.

Layered Double Hydroxide Derivatives for Polyolefin Upcycling.

While Ru-catalyzed hydrogenolysis holds significant promise in converting waste polyolefins into value-added alkane fuels, a major constraint is the high cost of noble metal catalysts. In this work, we propose, for the first time, that Co-based catalysts derived from CoAl-layered double hydroxide (LDH) are alternatives for efficient polyolefin hydrogenolysis. Leveraging the chemical flexibility of the LDH platform, we reveal that metallic Co species serve as highly efficient active sites for polyolefin hydrogenolysis. Furthermore, we introduced Ni into the Co framework to tackle the issue of restricted hydrogenation ability associated with contiguous Co-Co sites. In-situ analysis indicates that the integration of Ni induces electron transfer and facilitates hydrogen spillover. This dual effect synergistically enhances the hydrogenation/desorption of olefin intermediates, resulting in a significant reduction in the yield of low-value CH4 from 27.1 to 12.6%. Through leveraging the unique properties of LDH, we have developed efficient and cost-effective catalysts for the sustainable recycling and valorization of waste polyolefin materials.

Influence factors of CO adsorption on C2N-supported dual-atom catalysts unveiled by machine learning and twofold feature engineering.

Dual-atom catalysts (DACs) have emerged as a compelling frontier in the realm of the electrochemical carbon dioxide reduction reaction (CO2RR). However, elucidating the intrinsic properties of dual-atom pairs and their direct correlation with catalytic activity poses significant challenges. Herein, we investigate CO adsorption on 248 kinds of C2N-supported DACs and analyze the underlying structure-activity relationships of dual transition metal (TM) atoms based on density functional theory (DFT) calculations and machine learning (ML) models. Compared to the direct input of atomic features in the decision tree model of ML, we confirm that extra feature engineering with the introduction of the arithmetic combination of atomic features can better reflect the correlation of dual TM atoms on C2N-based DACs. Further feature importance analysis reveals a strong relationship between the last one occupied orbital radius (rv), group number (G) for dual TM atoms and the CO binding strength, as well as a potential connection with the d band centre (εd). Our work provides deeper insights into the design of DACs and highlights the significance of twofold feature engineering for the synergistic effects between dual TM atoms.

Stable Interfacial Ruthenium Species for Highly Efficient Polyolefin Upcycling.

The present polyolefin hydrogenolysis recycling cases acknowledge that zerovalent Ru exhibits high catalytic activity. A pivotal rationale behind this assertion lies in the propensity of the majority of Ru species to undergo reduction to zerovalent Ru within the hydrogenolysis milieu. Nonetheless, the suitability of zerovalent Ru as an optimal structural configuration for accommodating multiple elementary reactions remains ambiguous. Here, we have constructed stable Ru0-Ruδ+ complex species, even under reaction conditions, through surface ligand engineering of commercially available Ru/C catalysts. Our findings unequivocally demonstrate that surface-ligated Ru species can be stabilized in the form of a Ruδ+ state, which, in turn, engenders a perturbation of the σ bond electron distribution within the polyolefin carbon chain, ultimately boosting the rate-determining step of C-C scission. The optimized catalysts reach a solid conversion rate of 609 g·gRu-1·h-1 for polyethylene. This achievement represents a 4.18-fold enhancement relative to the pristine Ru/C catalyst while concurrently preserving a remarkable 94% selectivity toward valued liquid alkanes. Of utmost significance, this surface ligand engineering can be extended to the gentle mixing of catalysts in ligand solution at room temperature, thus rendering it amenable for swift integration into industrial processes involving polyolefin degradation.

Motivating Inert Strontium Manganate with Iridium Dopants as Efficient Electrocatalysts for Oxygen Evolution in Acidic Electrolyte.

The search for high-performance and low-cost electrocatalysts in acid conditions still remains a challenging target. Herein, iridium (Ir) doped strontium manganate (named as Irx -SMO) is proposed as an efficient and durable low-iridium electrocatalyst for water oxidation in acidic media. The Ir0.1 -SMO with 75% less iridium in comparison to that of iridium dioxide (IrO2 ) exhibits excellent performance for oxygen evolution reaction (OER), which is even better than most of the iridium-based oxide electrocatalysts. The theoretical outcomes confirm the activation of the inert manganese sites in strontium manganate by the incorporation of iridium dopants. This work reveals the boosted effect of the iridium dopants on the OER activity of strontium manganate, providing a strategy to tune the activity of manganese-based perovskites in electrocatalysis.

Core-Shell Design of Metastable Phase Catalyst Enables Highly-Performance Selective Hydrogenation.

Highly selective semihydrogenation of alkynes to alkenes is a highly important reaction for catalytic industry. Developing non-noble metal based catalysts with platinum group metal-like activity and selectivity is extremely crucial yet challenging. Metastable phase catalysts provide a potential candidate to realize high activity, yet the control of selectivity remains an open question. Here, this work first reports a metastable phase core-shell: face-centered cubic (fcc) phase Ag (10 at%) core-metastable hexagonal closest packed (hcp) phase Ni (90 at%) shell catalyst, which represents high conversion rate, high selectivity, and remarkable universality for the semihydrogenation of phenylacetylene and its derivatives. More impressively, a turnover frequency (TOF) value of 8241.8 h-1 is achieved, much higher than those of stable phase catalysts and reported platinum group metal based catalysts. Mechanistic investigation reveals that the surface of hcp Ni becomes more oxidized due to electron transfer from hcp Ni shell to fcc Ag core, which decreases the adsorption capacity of styrene on the metastable phase Ni surface, thus preventing full hydrogenation. This work has gained crucial research significance for the design of high performance metastable phase catalysts.