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Direct borohydride fuel cells (DBFCs) convert borohydride (NaBH4) chemical energy into clean electricity. However, catalytic active site deactivation in NaBH4 solution limits their performance and stability. We propose a strategy to regulate active sites in Co‐based catalysts using polypyrrole modification (Co−PX catalyst) to enhance electrochemical borohydride oxidation reaction (eBOR). As an anode catalyst, the synthesized Co−PX catalyst exhibits excellent eBOR performance in DBFCs, with current density of 280 mA ⋅ cm−2 and power density of 151 mW ⋅ cm−2, nearly twice that of the unmodified catalyst. The Co‐PX catalyst shows no degradation after 120‐hour operation, unlike the rapidly degrading control. In‐situ electrochemical attenuated total reflection Fourier‐transform infrared spectroscopy (ATR‐FTIRS) and density functional theory (DFT) suggest that polypyrrole‐modified carbon support regulate the charge distribution, increasing oxidation state and optimizing adsorption/desorption of intermediates. A possible reaction pathway is proposed. This work presents a promising strategy for efficient polymer‐modulated catalysts in advanced DBFCs. [ABSTRACT FROM AUTHOR]

• A method is developed to synthesize carbon-based high ni loaded single atom catalysts. • Ni single atom in catalysts with high photochemical activity exist as Ni-N and Ni-O. • The apparent rate constant for TC degradation by 5%Ni-C-Si is 0.169 min−1. • h +and ·O 2 − produced in photocatalysis are dominantly responsible for TC degradation. Environmental photocatalysis is a promising technology for treating antibiotics in wastewater. In this study, a supercritical carbonization method was developed to synthesize a single-atom photocatalyst with a high loading of Ni (above 5 wt.%) anchored on a carbon-nitrogen-silicate substrate for the efficient photodegradation of a ubiquitous environmental contaminant of tetracycline (TC). The photocatalyst was prepared from an easily obtained metal-biopolymer-inorganic supramolecular hydrogel, followed by supercritical drying and carbonization treatment. The low-temperature (300°C) supercritical ethanol treatment prevents the excessive structural degradation of hydrogel and greatly reduces the metal clustering and aggregation, which contributed to the high Ni loading. Atomic characterizations confirmed that Ni was present at isolated sites and stabilized by Ni-N and Ni-O bonds in a Ni-(N/O) 6 C/SiC configuration. A 5% Ni-C-Si catalyst, which performed the best among the studied catalysts, exhibited a wide visible light response with a narrow bandgap of 1.45 eV that could efficiently and repeatedly catalyze the oxidation of TC with a conversion rate of almost 100% within 40 min. The reactive species trapping experiments and electron spin resonance (ESR) tests demonstrated that the h+, and ·O 2 − were mainly responsible for TC degradation. The TC degradation mechanism and possible reaction pathways were provided also. Overall, this study proposed a novel strategy to synthesize a high metal loading single-atom photocatalyst that can efficiently remove TC with high concentrations, and this strategy might be extended for synthesis of other carbon-based single-atom catalysts with valuable properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Amorphous nano-metal catalysts often exhibit appealing catalytic properties, because the intrinsic linear scaling relationship can be broken. However, accurate control synthesis of amorphous nano-metal catalysts with desired size and morphology is a challenge. In this work, we discover that Cu(0) could be oxidized to amorphous CuxO species by supercritical CO2. The formation process of the amorphous CuxO is elucidated with the aid of machine learning. Based on this finding, a method to prepare Cu nanoparticles with an amorphous shell is proposed by supercritical CO2 treatment followed by electroreduction. The unique feature of this method is that the size of the particles with amorphous shell can be easily controlled because their size depends on that of the original crystal Cu nanoparticles. Moreover, the thickness of the amorphous shell can be easily controlled by CO2 pressure and/or treatment time. The obtained amorphous Cu shell exhibits high selectivity for C2+ products with the Faradaic efficiency of 84% and current density of 320 mA cm−2. Especially, the FE of C2+ oxygenates can reach up to 65.3 %, which is different obviously from the crystalline Cu catalysts. Amorphous metal catalysts often exhibit appealing catalytic properties, however, accurate control synthesis of amorphous nano-metal catalysts is a challenge. Here, the authors report a feasible strategy to prepare the amorphous Cu catalysts by supercritical CO2 treatment followed by electroreduction. The resulted catalyst shows high selectivity towards multi-carbon products for CO2 electroreduction. [ABSTRACT FROM AUTHOR]

To achieve practical application of fuel cell, it is vital to develop highly efficient and durable Pt‐free catalysts. Herein, we prepare atomically dispersed ZnNC catalysts with Zn‐Pyrrolic‐N4 moieties and abundant mesoporous structure. The ZnNC‐based anion‐exchange membrane fuel cell (AEMFC) presents an ultrahigh peak power density of 1.63 and 0.83 W cm−2 in H2‐O2 and H2‐air (CO2‐free), and also exhibits long‐term stability with more than 120 and 100 h for H2‐air (CO2‐free) and H2‐O2, respectively. Density functional calculations further unveil that the Zn‐Pyrrolic‐N4 structure is the origin of high activity of as‐synthesized ZnNC catalyst, while the Zn‐Pyridinic‐N4 moiety is inactive for oxygen reduction reaction (ORR), which successfully explain the puzzle why most Zn‐metal‐organic framework ‐derived ZnNC catalysts in previous reports did not present good ORR activity because of their Zn‐Pyridinic‐N4 moieties. This work offers a new route for speeding up development of AEMFCs. [ABSTRACT FROM AUTHOR]

Fine‐tuning single‐atom catalysts (SACs) to surpass their activity limit remains challenging at their atomic scale. Herein, we exploit p‐type semiconducting character of SACs having a metal center coordinated to nitrogen donors (MeNx) and rectify their local charge density by an n‐type semiconductor support. With iron phthalocyanine (FePc) as a model SAC, introducing an n‐type gallium monosulfide that features a low work function generates a space‐charged region across the junction interface, and causes distortion of the FeN4 moiety and spin‐state transition in the FeII center. This catalyst shows an over two‐fold higher specific oxygen‐reduction activity than that of pristine FePc. We further employ three other n‐type metal chalcogenides of varying work function as supports, and discover a linear correlation between the activities of the supported FeN4 and the rectification degrees, which clearly indicates that SACs can be continuously tuned by this rectification strategy. [ABSTRACT FROM AUTHOR]

Considerable attention has been drawn to tune the geometric and electronic structure of interfacial catalysts via modulating strong metal-support interactions (SMSI). Herein, we report the construction of a series of TiO2−x/Ni catalysts, where disordered TiO2−x overlayers immobilized onto the surface of Ni nanoparticles (~20 nm) are successfully engineered with SMSI effect. The optimal TiO2−x/Ni catalyst shows a CO conversion of ~19.8% in Fischer–Tropsch synthesis (FTS) process under atmospheric pressure at 220 °C. More importantly, ~64.6% of the product is C2+ paraffins, which is in sharp contrast to the result of the conventional Ni catalyst with the main product being methane. A combination study of advanced electron microscopy, multiple in-situ spectroscopic characterizations, and density functional theory calculations indicates the presence of Niδ−/TiO2−x interfacial sites, which could bind carbon atom strongly, inhibit methane formation and facilitate the C-C chain propagation, lead to the production of C2+ hydrocarbon on Ni surface. Considerable attention has been drawn to tune the geometric and electronic structure of interfacial catalysts via modulating strong metal-support interactions (SMSI). Here the authors report the remarkable catalytic performance of CO hydrogenation over an interfacial TiO2−x/Ni catalyst by means of SMSI. [ABSTRACT FROM AUTHOR]

Electrochemical alcohols oxidation offers a promising approach to produce valuable chemicals and facilitate coupled H2 production. However, the corresponding current density is very low at moderate cell potential that substantially limits the overall productivity. Here we report the electrooxidation of benzyl alcohol coupled with H2 production at high current density (540 mA cm−2 at 1.5 V vs. RHE) over a cooperative catalyst of Au nanoparticles supported on cobalt oxyhydroxide nanosheets (Au/CoOOH). The absolute current can further reach 4.8 A at 2.0 V in a more realistic two-electrode membrane-free flow electrolyzer. Experimental combined with theoretical results indicate that the benzyl alcohol can be enriched at Au/CoOOH interface and oxidized by the electrophilic oxygen species (OH*) generated on CoOOH, leading to higher activity than pure Au. Based on the finding that the catalyst can be reversibly oxidized/reduced at anodic potential/open circuit, we design an intermittent potential (IP) strategy for long-term alcohol electrooxidation that achieves high current density (>250 mA cm−2) over 24 h with promoted productivity and decreased energy consumption. Electrochemical alcohol oxidation offers a promising approach to produce valuable chemicals that can be paired with fuel-producing reactions. Here, authors utilize gold and cobalt oxyhydroxide nanomaterials to obtain industrially-relevant electrolyzer current densities for benzyl alcohol oxidation. [ABSTRACT FROM AUTHOR]

As an emerging frontier, dual‐atom catalysts (DACs) have sparked broad interest in energy catalysis, however the undesired thermal atomic migration during synthesis process pose significant challenge in enabling further applications. Herein, an interfacial cladding strategy is reported to construct monodispersed dual‐atom metal sites (metal = Fe, Cu, or Ir), derived from metal dimer molecule functionalized metal‐organic frameworks. First, metal dimer molecule is immobilized at the surface of cubic ZIF‐8 by the interfacial cladding of polydopamine, thus preventing the potentially thermal migration of metal atoms during pyrolysis. Then, the paired metal atoms are anchored onto a hollow carbon nanocage and achieve nitrogen coordinated dual‐atom metal sites after annealing at 900 °C. Representatively, the resultant dual Fe catalysts exhibit remarkable activity for electrocatalytic oxygen reduction reaction with half‐wave potential of 0.951 and 0.816 V in alkaline and acidic media, respectively. The findings open up an avenue for the rational design of dual‐atom catalysts. [ABSTRACT FROM AUTHOR]

Increasing the portion of highly active metal centers in atomically dispersed MNC catalysts is significant for the overall oxygen reduction reaction (ORR) performance. A "facet strain strategy" is designed by using a trans‐layer compressive strain of the {110} facet of FeCo nanoparticles encapsulated in graphitic FeNC layers to further activate the primitive FeN4 catalytic centers on the graphitic sub‐layer that are omitted in commonly direct access activation strategies. Using X‐ray absorption near‐edge spectroscopy and extended X‐ray absorption fine structure, the highly active FeN4 type is detected with compressed FeN bonds. Density functional theory calculation discloses that, in virtue of lattice mismatch, FeCo {110} facets transmit a trans‐layer compressive strain to reconstruct the FeN4 sites on surrounding graphitic sub‐layers to optimize the Fe‐OH* adsorption energy in the rate‐determining step. The redesigned catalyst exhibits enhanced ORR activity, outperforming the primitive FeNC and commercial Pt/C benchmarks. This study will enrich insights toward developing MN4 and nanoparticle composite electrocatalysts. [ABSTRACT FROM AUTHOR]

The development of highly active single‐atom catalysts (SACs) and identifying their intrinsic active sites in oxidizing industrial hazardous hydrocarbons are challenging prospects. Tuning the electronic metal‐support interactions (EMSIs) is valid for modulating the catalytic performance of SACs. We propose that the modulation of the EMSIs in a Pt1−CuO SAC significantly promotes the activity of the catalyst in acetone oxidation. The EMSIs promote charge redistribution through the unified Pt−O−Cu moieties, which modulates the d‐band structure of atomic Pt sites, and strengthens the adsorption and activation of reactants. The positively charged Pt atoms are superior for activating acetone at low temperatures, and the stretched Cu−O bonds facilitate the activation of lattice oxygen atoms to participate in subsequent oxidation. We believe that this work will guide researchers to engineer efficient SACs for application in hydrocarbon oxidation reactions. [ABSTRACT FROM AUTHOR]

Regulating the coordination environment via heteroatoms to break the symmetrical electronic structure of M‐N4 active sites provides a promising route to engineer metal‐nitrogen‐carbon catalysts for electrochemical CO2 reduction reaction. However, it remains challenging to realize a site‐specific introduction of heteroatoms at atomic level due to their energetically unstable nature. Here, this paper reports a facile route via using an oxygen‐ and nitrogen‐rich metal–organic framework (MOF) (IRMOF‐3) as the precursor to construct the Fe‐O and Fe‐N chelation, simultaneously, resulting in an atomically dispersed axial O‐coordinated FeN4 active site. Compared to the FeN4 active sites without O coordination, the formed FeN4‐O sites exhibit much better catalytic performance toward CO, reaching a maximum FECO of 95% at −0.50 V versus reversible hydrogen electrode. To the best of the authors' knowledge, such performance exceeds that of the existing Fe‐N‐C‐based catalysts derived from sole N‐rich MOFs. Density functional theory calculations indicate that the axial O‐coordination regulates the binding energy of intermediates in the reaction pathways, resulting in a smoother desorption of CO and increased energy for the competitive hydrogen production. [ABSTRACT FROM AUTHOR]

Electrochemical synthesis of NH3 is a carbon‐free alternative to the traditional Haber–Bosch process. Obtaining NH3 from environmental pollutants, such as nitrates or nitrites, is a more practical route than from the nitrogen reduction reaction (NRR) due to the difficult cleavage of the inert triple bond of nitrogen gas. Here, a novel heterogeneous catalyst is reported based on iron (Fe) single‐atoms supported on 2D MoS2 (Fe‐MoS2) for the nitrate reduction reaction (NO3RR). Fe‐MoS2 exhibits remarkable performance with a maximum Faradaic efficiency of 98% for NO3RR to NH3 at an onset potential of −0.48 V versus the reversible hydrogen electrode (RHE) as confirmed by the isotopic nuclear magnetic resonance (NMR) analyses. Density functional theory (DFT) calculations reveal that the enhanced selectivity for the production of NH3 from single Fe atoms supported on MoS2 is attributed to a reduced energy barrier of 0.38 eV associated with de‐oxidation of *NO to *N. The catalysts are coupled to an InGaP/GaAs/Ge triple‐junction solar cell to demonstrate a solar‐to‐ammonia (STA) conversion efficiency of 3.4% and a yield rate of 510 µg h−1 cm−2. The results open new avenues for the design of single‐atom catalysts (SAC) for the realization of solar‐driven ammonia production. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of CO2 to valuable fuels is appealing for CO2 fixation and energy storage. The Cu‐based catalysts feature unique superiorities, but achieving high ethylene selectivity is still restricted. In this study, we propose the anchoring of an ionic liquid (IL) on a Cu electrocatalyst for improving the electrochemical CO2 reduction to ethylene. In a water‐based electrolyte and a commonly used H‐type cell, a high ethylene Faradaic efficiency of 77.3 % was achieved at −1.49 V (vs. RHE). Experimental and theoretical studies reveal that an IL can modify the electronic structure of a Cu catalyst through its interaction with Cu, making it more conducive to *CO dimerization for ethylene formation. [ABSTRACT FROM AUTHOR]

Non‐precious‐metal (NPM) catalysts often face the formidable challenge of a trade‐off between long‐term stability and high activity, which has not yet been widely addressed. Herein we propose a distinct molecule‐selective fence as a promising concept to solve this activity‐stability trade‐off. The fence encloses the catalyst and prevents species poisonous to the catalyst from reaching it, but allows catalytic reaction‐related species to diffuse freely. We constructed a CoS2 fence layer on the external surface of highly active cobalt‐doped MoS2, achieving a remarkable catalytic stability towards the alkaline hydrogen evolution reaction and improved activity. In situ spectroscopy uncovered the underlying molecular mechanism of the CoS2 fence for breaking the activity‐stability trade‐off of the MoS2 catalyst. This work offers valuable guidance for rationally designing efficient and stable NPM catalysts. [ABSTRACT FROM AUTHOR]

Selective oxidation of ammonia to nitric oxide over platinum-group metal alloy gauzes is the crucial step for nitric acid production, a century-old yet greenhouse gas and capital intensive process. Therefore, developing alternative ammonia oxidation technologies with low environmental impacts and reduced catalyst cost are of significant importance. Herein, we propose and demonstrate a chemical looping ammonia oxidation catalyst and process to replace the costly noble metal catalysts and to reduce greenhouse gas emission. The proposed process exhibit near complete NH3 conversion and exceptional NO selectivity with negligible N2O production, using nonprecious V2O5 redox catalyst at 650 oC. Operando spectroscopy techniques and density functional theory calculations point towards a modified, temporally separated Mars-van Krevelen mechanism featuring a reversible V5+/V4+ redox cycle. The V = O sites are suggested to be the catalytically active center leading to the formation of the oxidation products. Meanwhile, both V = O and doubly coordinated oxygen participate in the hydrogen transfer process. The outstanding performance originates from the low activation energies for the successive hydrogen abstraction, facile NO formation as well as the easy regeneration of V = O species. Our results highlight a transformational process in extending the chemical looping strategy to producing base chemicals in a sustainable and cost-effective manner. This study reports a fundamentally new and commercially promising chemical looping ammonia oxidation scheme using an inexpensive transition metal oxide, and provides mechanistic insight into the oxygen species governing ammonia oxidation. [ABSTRACT FROM AUTHOR]

The article titled "Front Cover: Polypyrrole regulates Active Sites in Co-based Catalyst in Direct Borohydride Fuel Cells" discusses the use of direct borohydride fuel cells (DBFCs) to convert borohydride chemical energy into clean electricity. The study proposes a strategy to enhance the electrochemical borohydride oxidation reaction (eBOR) at the anode by regulating active sites in Co-based catalysts using polypyrrole modification. The researchers found that the polypyrrole-modified carbon support optimizes the adsorption and desorption of intermediates by regulating the charge distribution around Co species. This study suggests a new approach for designing electrocatalysts with high eBOR performance by manipulating active sites with polymers. [Extracted from the article]

Developing single‐atom electrocatalysts with high activity and superior selectivity at a wide potential window for CO2 reduction reaction (CO2RR) still remains a great challenge. Herein, a porous NiNC catalyst containing atomically dispersed NiN4 sites and nanostructured zirconium oxide (ZrO2@Ni‐NC) synthesized via a post‐synthetic coordination coupling carbonization strategy is reported. The as‐prepared ZrO2@Ni‐NC exhibits an initial potential of −0.3 V, maximum CO Faradaic efficiency (F.E.) of 98.6% ± 1.3, and a low Tafel slope of 71.7 mV dec−1 in electrochemical CO2RR. In particular, a wide potential window from −0.7 to −1.4 V with CO F.E. of above 90% on ZrO2@Ni‐NC far exceeds those of recently developed state‐of‐the‐art CO2RR electrocatalysts based on NiN moieties anchored carbon. In a flow cell, ZrO2@Ni‐NC delivers a current density of 200 mA cm−2 with a superior CO selectivity of 96.8% at −1.58 V in a practical scale. A series of designed experiments and structural analyses identify that the isolated NiN4 species act as real active sites to drive the CO2RR reaction and that the nanostructured ZrO2 largely accelerates the protonation process of *CO2− to *COOH intermediate, thus significantly reducing the energy barrier of this rate‐determining step and boosting whole catalytic performance. [ABSTRACT FROM AUTHOR]

Using renewable electricity to drive CO2 electroreduction is an attractive way to achieve carbon‐neutral energy cycle and produce value‐added chemicals and fuels. As an important platform molecule and clean fuel, methanol requires 6‐electron transfer in the process of CO2 reduction. Currently, CO2 electroreduction to methanol suffers from poor efficiency and low selectivity. Herein, we report the first work to design atomically dispersed Sn site anchored on defective CuO catalysts for CO2 electroreduction to methanol. It exhibits high methanol Faradaic efficiency (FE) of 88.6 % with a current density of 67.0 mA cm−2 and remarkable stability in a H‐cell, which is the highest FE(methanol) with such high current density compared with the results reported to date. The atomic Sn site, adjacent oxygen vacancy and CuO support cooperate very well, leading to higher double‐layer capacitance, larger CO2 adsorption capacity and lower interfacial charge transfer resistance. Operando experiments and density functional theory calculations demonstrate that the catalyst is beneficial for CO2 activation via decreasing the energy barrier of *COOH dissociation to form *CO. The obtained key intermediate *CO is then bound to the Cu species for further reduction, leading to high selectivity toward methanol. [ABSTRACT FROM AUTHOR]

Atomically dispersed Pt species are advocated as a promising electrocatalyst for the oxygen reduction reaction (ORR) to boost noble metal utilization efficiency. However, when assembled on various substrates, isolated Pt single atoms are often demonstrated to proceed through the two‐electron ORR pathway due to the unfavorable O─O bond cleavage thermodynamics in the absence of catalytic ensemble sites. In addition, although their distinct local coordination environments at the exact single active sites are intensively explored, the interactions and synergy between closely neighboring single atom sites remain elusive. Herein, atomically dispersed Pt monomers strongly interacting on a Mo2C support is demonstrated as a model catalyst in the four‐electron ORR, and the beneficial interactions between two closely neighboring and yet non‐contiguous Pt single atom sites (named as quasi‐paired Pt single atoms) are shown. Compared to isolated Pt single atom sites, the quasi‐paired Pt single atoms deliver a superior mass activity of 0.224 A mg−1Pt and near‐100% selectivity toward four‐electron ORR due to the synergistic interaction from the two quasi‐paired Pt atom sites in modulating the binding mode of reaction intermediates. Our first‐principles calculations reveal a unique mechanism of such quasi‐paired configuration for promoting four‐electron ORR. [ABSTRACT FROM AUTHOR]

Single‐atom alloys (SAAs) have ignited a surge of unprecedented interest as the advanced nanomaterials and opened many opportunities for wide applications. Herein, 3D porous aerogels comprising ionic liquid (IL) functionalized PdBi SAA building blocks with atomically dispersed Bi on Pd nanowires (IL/Pd50Bi1) are synthesized with accelerated gelation kinetics, which could serve as high‐efficiency electrocatalysts for ethanol oxidation reaction (EOR). Benefiting from the unique structures of aerogels including synergistic effects of PdBi SAA nanowire networks and interface engineering, the optimized IL/Pd50Bi1 aerogels display a nearly fourfold enhancement in mass activity and boosted stability for EOR compared to commercial Pd/C. Density functional theory calculations further demonstrate that isolated Bi atoms on Pd nanowire networks decrease the energy barrier of the rate‐determining step, resulting in excellent electrocatalytic activity for EOR. This work provides a promising method for developing efficient SAA catalysts for fuel electrooxidation. [ABSTRACT FROM AUTHOR]

The modulation effect has been widely investigated to tune the electronic state of single‐atomic M‐N‐C catalysts to enhance the activity of oxygen reduction reaction (ORR). However, the in‐depth study of modulation effect is rarely reported for the isolated dual‐atomic metal sites. Now, the catalytic activities of Fe‐N4 moiety can be enhanced by the adjacent Pt‐N4 moiety through the modulation effect, in which the Pt‐N4 acts as the modulator to tune the 3d electronic orbitals of Fe‐N4 active site and optimize ORR activity. Inspired by this principle, we design and synthesize the electrocatalyst that comprises isolated Fe‐N4/Pt‐N4 moieties dispersed in the nitrogen‐doped carbon matrix (Fe‐N4/Pt‐N4@NC) and exhibits a half‐wave potential of 0.93 V vs. RHE and negligible activity degradation (ΔE1/2=8 mV) after 10000 cycles in 0.1 M KOH. We also demonstrate that the modulation effect is not effective for optimizing the ORR performances of Co‐N4/Pt‐N4 and Mn‐N4/Pt‐N4 systems. [ABSTRACT FROM AUTHOR]

Fundamental understanding of the dependence between the structure and composition on the electrochemical CO2 reduction reaction (CO2RR) would guide the rational design of highly efficient and selective electrocatalysts. A major impediment to the deep reduction CO2 to multi‐carbon products is the complexity of carbon–carbon bond coupling. The chemically well‐defined catalysts with atomically dispersed dual‐metal sites are required for these C−C coupling involved processes. Here, we developed a catalyst (BIF‐102NSs) that features Cl− bridged dimer copper (Cu2) units, which delivers high catalytic activity and selectivity for C2H4. Mechanistic investigation verifies that neighboring Cu monomers not only perform as regulator for varying the reaction barrier, but also afford distinct reaction paths compared with isolated monomers, resulting in greatly improved electroreduction performance for CO2. [ABSTRACT FROM AUTHOR]

Achieving efficient activation of H 2 O 2 in the tumor microenvironment (TME) and further improving the therapeutic efficiency is a great challenge in chemodynamic therapy against cancer. Herein, inspired by natural enzymes, atomically dispersed catalysts with Fe-Cu hetero-binuclear active sites on hollow nitrogen-doped carbon nanospheres (FeCuNC) are synthesized as catalytic nanomedicines for cancer therapy. We found that Fe-Cu hetero-binuclear sites in FeCuNC can catalytically dissociate the O–O bonds in H 2 O 2 molecules more easily than those of single-Fe sites. Besides, the intrinsic photothermal effect of FeCuNC not only further accelerates H 2 O 2 decomposition to produce abundant reactive oxygen species but also achieves synergistically chemodynamic therapy and photothermal therapy to induce cancer cell apoptosis and restrain tumor growth. Moreover, FeCuNC can accurately identify sentinel lymph node metastasis and effectively suppress tumor metastasis and recurrence. This work will provide an advanced strategy for the design of advanced catalysts for H 2 O 2 activation in TME, which holds great promise for practical clinical applications. [Display omitted] • Atomically dispersed catalysts with Fe-Cu hetero-binuclear active sites are successfully constructed. • The Fe-Cu hetero-binuclear active sites can promote the dissociation of O–O in H 2 O 2. • The intrinsic photothermal effect can accelerate H 2 O 2 decomposition to produce abundant reactive oxygen species. • FeCuNC can accurately identify SLN metastasis and effectively suppress tumor metastasis and recurrence. [ABSTRACT FROM AUTHOR]

• The catalyst itself contains base site that can promote the deprotonation of benzyl alcohol effectively. • The two components of Cu 2 O and Cu 3 (OH) 2 (CO 3) 2 have a synergistic catalytic effect. • The catalyst has a hierarchically macro- and mesoporous structure. To develop high-performance catalyst for the selective oxidation of benzyl alcohols to benzyl aldehydes is of great importance. Here we synthesized a novel catalyst of cuprous oxide/basic cuprous carbonate (Cu 2 O/Cu 3 (OH) 2 (CO 3) 2) composite by supercritical CO 2. The two components of Cu 2 O and Cu 3 (OH) 2 (CO 3) 2 have a synergistic catalytic effect to facilitate the oxidation of alcohol. Moreover, the catalyst has a hierarchically macro- and mesoporous structure, which favors the exposure of active sites, adsorption of reactants on the catalyst surface and mass transfer. Owing to these unique features, the as-synthesized Cu 2 O/Cu 3 (OH) 2 (CO 3) 2 shows high performance for the oxidation of benzyl alcohol to benzyl aldehyde at 75 °C under atmospheric O 2. [ABSTRACT FROM AUTHOR]

A template-engaged multistep synthesis process is developed to fabricate ultrathin carbon nanosheets assembled hierarchical nanoboxes embedded with dense Mo-N 4 active sites, which exhibited excellent activity and superb stability for oxygen reduction reaction. [Display omitted] • Unique hierarchical SA-Mo-C nanoboxes were fabricated via a template-engaged multistep synthesis process. • Comprehensive characterizations including EXAFS reveal Mo-N 4 atomic sites were formed and densely dispersed in the SA-Mo-C nanoboxes. • SA-Mo-C nanoboxes exhibited better ORR performance compared to commercial Pt/C catalysts. Construction of single-atom catalysts (SACs) with maximally exposed active sites remains a challenging task mainly because of the lack of suitable host matrices. In this study, hierarchical N -doped carbon nanoboxes composed of ultrathin nanosheets with dispersed atomic Mo (denoted as hierarchical SA-Mo-C nanoboxes) were fabricated via a template-engaged multistep synthesis process. Comprehensive characterizations, including X-ray absorption fine structure analysis, reveal the formation of Mo-N 4 atomic sites uniformly anchored on the hierarchical carbon nanoboxes. The prepared catalysts offer structural and morphological advantages, including ultrathin nanosheet units, unique hollow structures and abundant active Mo-N 4 species, that result in excellent activity with a half-wave potential of 0.86 V vs. RHE and superb stability for the oxygen reduction reaction in 0.1 M KOH; thus, the catalysts are promising air–cathode catalysts for Zn-air batteries with a high peak power density of 157.6 mW cm−2. [ABSTRACT FROM AUTHOR]

[Display omitted] • M single atom (M = Fe, Co, Ni) anchored on Ru nanoclusters were prepared to form M 1 Ru SAA. • Co 1 Ru SAA shows the highest NH 3 synthesis rate and TOF Ru value. • Compared with Co-Ru nanoparticle alloy, Co 1 Ru SAA exhibits lower work function and up-shift d band center. • SAA structure effectively tune N 2 activation pathway. The desire of green ammonia (NH 3) production requires efficient catalysts that could operate at mild conditions. However, the activity of catalysts is restricted by scaling relation that low activation energy of N 2 is in conjunction with the over-strong affinity of intermediates, which blocks adsorption sites of catalyst and hinders NH 3 production. Single atom alloy (SAA) is an efficient approach to circumvent this relation. In the present work, we offer a feasible strategy of preparing M 1 Ru (M = Fe, Co, Ni) SAA. Our studies show that Co 1 Ru SAA has the highest NH 3 synthesis rate and the largest TOF Ru value among M 1 Ru SAA. Compared with CoRu nanoparticle alloy (NPA), Co 1 Ru SAA has stronger electronic interaction between Co and Ru, which induces lower work function and up-shift d band center toward Fermi level for Co 1 Ru SAA, thus promoting N 2 activation. Meanwhile, the unique SAA structure could effectively tune N 2 activation pathway. Those findings make a contribution to the development of advanced catalysts for efficient NH 3 synthesis at mild conditions. [ABSTRACT FROM AUTHOR]

Single-atom catalysts (SACs) have emerged as one of the most competitive catalysts toward a variety of important electrochemical reactions, thanks to their maximum atom economy, unique electronic and geometric structures. However, the role of SACs supports on the catalytic performance does not receive enough research attentions. Here, we report an efficient route for synthesis of single atom Zn loading on the N-doped carbon nano-onions (ZnN/CNO). ZnN/CNO catalysts show an excellent high selectivity for CO 2 electro-reduction to CO with a Faradaic efficiency of CO (FE CO) up to 97% at −0.47 V (vs. reversible hydrogen electrode, RHE) and remarkable durability without activity decay. To our knowledge, ZnN/CNO is the best activity for the Zn based catalysts up to now, and superior to single atom Zn loading on the two-dimensional planar and porous structure of graphene substrate, although the graphene with larger surface area. The exact role of such carbon nano-onions (CNO) support is studied systematically by coupling characterizations and electrochemistry with density functional theory (DFT) calculations, which have attributed such good performance to the increased curvature. Such increased curvature modifies the surface charge, which then changes the adsorption energies of key intermediates, and improves the selectivity for CO generation accordingly. [ABSTRACT FROM AUTHOR]

Urea is of great importance for the survival and development of mankind because of its advantages in effectively increasing crop yields. A novel carbon-supported indium-doped bismuth nanoparticles (Bi: 10 %In/C NPs) was prepared for the synthesis of urea via the co-activated reduction of nitrate and CO 2 with an average Faraday efficiency (FE) of 20.31 % and urea yield (R urea) of 606.38 μg mg−1 h−1. Interestingly, the In doped here not only serves as the active site, but also acts as an activator to stimulate the activity of Bi through electronic interaction, thus making Bi also the active site for the electrocatalytic C-N coupling reaction. Simultaneously, the key intermediates of the reaction are revealed to be *NH 2 and *CO. This work provides further insight into the role of indium in the electrocatalytic C-N coupling for the synthesis of urea, which gives a direction for thinking about the design and construction of subsequent highly efficient electrocatalysts. A novel catalyst based on carbon-supported In-doped Bi nanoparticles (Bi:10 % In/C NPs) was prepared for the co-activated reduction of nitrate and CO 2 for the synthesis of urea with average FE and urea yield of 20.31 % and 606.38 μg mg−1 h−1 at − 0.45 V vs. RHE. The key intermediates of the reaction are revealed to be *NH 2 and *CO. Interestingly, experimental results show that the doped In acts not only as the active site but also as an "activator", stimulating the activity of Bi through electronic interactions, thus making Bi also the active site for electrocatalytic C-N coupling reactions. [Display omitted] ● A bismuth-based catalyst well suited for the electrochemical synthesis of urea (FE: 20.31 %, R urea : 606.38 μg mg−1 h−1) was prepared by a simple room temperature reduction method based on the property of bismuth to inhibit competitive hydrogen evolution reactions. ● A strategy for the preparation of electrocatalysts for highly efficient urea synthesis using direct activation of bismuth by indium is proposed for the first time. ● Theindium in the prepared Bi:In/C not only directly participates in the synthesis of urea as the active site, but also acts as an activator to activate the inert bismuth, so that bismuth also becomes the active site of the C-N coupling reaction, thus greatly improving the efficiency and stability for the synthesis of urea. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ru clusters are immobilized on hierachical Ni 3 N arrays. • The interfacial Ru atoms enable long-range Ni atoms as active sites via electron delocalization. • The H 2 O and H* adsorption energies are strengthened and weakened, respectively. • An outperforming Pt/C benchmark activity is achieved at ≥ 125 mA cm−2. Hydrogen (H 2) production from alkaline water electrocatalysis is economically appealing yet significantly hindered by the sluggish H 2 O adsorption and H* binding kinetics on active sites during hydrogen evolution reaction (HER). Herein, we interfacially immobilize Ru clusters on the hierarchical nickel nitride (Ru-Ni 3 N) nanosheet arrays via the filling of Ru3+ species into the metal vacancies of nickel hydroxide precursors and the subsequent controllable nitridation. The optimized Ru-Ni 3 N shows the outstanding HER performance, affording a 30-fold rise in the intrinsic activity of Ni sites, a outperforming-Pt/C overpotential at ≥ 125 mA cm−2 while remaining a robust stability. We further establish by a combined study of density functional theory (DFT) calculations with experimental analyses that long-range Ni sites around Ru sites act as active sites via the electron delocalization, remarkably weakening the H 2 O adsorption and H* binding barriers for enhancing the alkaline HER kinetics. Moreover, it also demonstrates an excellent pH-universal HER and overall water splitting performance. [ABSTRACT FROM AUTHOR]

In this study, phosphate FeCo(H 3 O)(PO 4) 2 nanosheet arrays (NAs) were synthesized using an electrochemical strategy. FeCo(H 3 O)(PO 4) 2 NAs as precatalyst could undergo significant self-reconstruction, including leaching of phosphate anions and electro-oxidation of Co2+ during anodizing at the potential range of oxygen evolution reaction (OER) in 1 M KOH solution, eventually resulting in the formation of Fe 0.5 Co 0.5 OOH NAs with low crystallinity. The high content of Fe in Fe 0.5 Co 0.5 OOH NAs promoted the formation of active Fe3+–O–Fe3+ motifs that increased OER occurrence. Additionally, Fe incorporation increased the ratio of the reaction rate constants of oxygen evolution to Co3+/Co4+ (k OER /k M,ox) and enhanced the reaction order on the hydroxyl ion. These factors significantly contributed to the outstanding OER catalytic performances of Fe 0.5 Co 0.5 OOH NAs. [Display omitted] Fe 0.5 Co 0.5 OOH nanosheet arrays (NAs) were fabricated via electrochemical self-reconstruction of CoFe(H 3 O)(PO 4) 2 NAs. Benefiting from the formation of active Fe3+–O–Fe3+ motifs, Fe incorporation increased the ratio of the reaction rate constants of oxygen evolution to Co3+/Co4+ (k OER /k M,ox) and enhanced the reaction order on the hydroxyl ion, Fe 0.5 Co 0.5 OOH NAs exhibited outstanding catalytic performances of oxygen evolution reaction. • Fe 0.5 Co 0.5 OOH was synthesized via self-reconstruction of CoFe(H 3 O)(PO 4) 2. • High content of Fe promoted the formation of [di-μ-O(OH)] Fe3+–O–Fe3+ in Fe 0.5 Co 0.5 OOH. • [di-μ-O(OH)] Fe3+–O–Fe3+ motifs in oxyhdroxide acted as OER active sites. • Fe incorporation varied the electrokinetic parameters of oxyhydroxide. • [di-μ-O(OH)] Fe3+–O–Fe3+ motifs further increased the reaction order on the OH-. [ABSTRACT FROM AUTHOR]

• Enzyme-like Fe-N 5 single atom catalyst was employed for efficient sensing application. • Highly sensitive simultaneous sensing of dopamine and uric acid was realized. • The corresponding biosensor has been successfully applied for real human serum sample detection. Simultaneous highly sensitive and accurate detection of dopamine (DA) and uric acid (UA) is of great importance since they are important biomolecules that are commonly coexisted in the human body and play a crucial role in numerous physiological and pathological features. In this work, Fe-N 5 single atom catalyst (SAC) supported on graphene was firstly employed for simultaneous electrochemical detection DA and UA. Owing to its unique electronic structure and abundant active sites, under optimal conditions, the enzyme-like Fe-N 5 SAC constructed electrochemical (bio)sensor exhibits excellent linear characteristic responses in the range of 0.005–500 and 0.01–480 µM, as well as the low limit of detection of 0.007 and 0.027 nM for DA and UA, respectively. More critically, the developed electrochemical system shows promising merits of exceptional stability, good repeatability, and, consequently, it was successfully applied for simultaneous sensitive detection of DA and UA in human serum samples. [ABSTRACT FROM AUTHOR]