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Owing to the inertness of CO2 molecules, the development of highly active photocatalysts for CO2 reduction reactions (CO2RR) remains a formidable challenge. Here, we designed an MXene-based single-atom Fe co-catalyst (Fe1/Ti3−xC2Ty) featuring fast Ti–Fe electron channels to achieve enhanced CO2RR performance. The synthesized Fe1/Ti3−xC2Ty exhibited a CO yield of 259.0 μmol g−1 h−1 without the addition of any organic sacrificial agents. The experimental and computational results reveal that, electrons transfer from Ti to Fe and then accumulate at the active sites, which facilitates the transfer of charges and enhances the activation of CO2 molecules. This work provides a new direction of MXene-based non-noble-metal monoatomic catalysts for efficient photoreduction of CO2 under gas–solid photocatalytic conditions with pure water. [ABSTRACT FROM AUTHOR]

Using water as a hydrogen/oxygen source for electrocatalytic production of high-value chemicals is highly desirable from a sustainability perspective due to the pivotal role of reduction/oxidation reactions in chemical industry. However, competition from water splitting into H2/O2 typically limits the electron efficiency and process economy. In this work, an oxygen vacancy-rich NiFe-layered double hydroxide (NiFe-LDH)-derived catalyst was obtained by the reduction of monolayer NiFe-LDH (NiFe-mono) at 400 °C in a 10% H2/Ar atmosphere. NiFe-400 showed outstanding activity for the electrocatalytic reduction of p-nitrophenol (p-NP) to p-aminophenol (p-AP) in 1 M KOH, delivering a faradaic efficiency (FE) above 99%. Under continuous electrolytic reduction conditions, 97% FE could be maintained even at 100 mM p-NP. In situ XAFS and DFT theoretical calculations revealed that the Fe site is the main active site, and the existence of oxygen defects promotes the interaction between the active site and the intermediate of the p-NP hydrogenation reaction. Furthermore, in order to utilize the oxygen evolved by water splitting, a paired electrolysis cell was developed that allowed the simultaneous reduction of p-NP to p-AP over NiFe-LDH at the cathode and 5-hydroxymethylfurfural (HMF) oxidation to 2,5-furandicarboxylic acid (FDCA) over a monolayered NiCo-LDH catalyst (NiCo-mono) at the anode, with the combined anode and cathode FE being >190%. Results encourage the wider use of defect-rich LDHs in green chemical synthesis with water as a hydrogen/oxygen source. [ABSTRACT FROM AUTHOR]

Developing a cost-effective and highly efficient electrocatalyst for the hydrogen economy remains a significant challenge due mainly to the high overpotentials of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we propose an effective modification strategy by encapsulating a small amount of Ru nanoclusters (NCs) into g-C3N4 rich in N-vacancies (VN). Systematic experiments were carried out to investigate the formation process of Ru NCs and demonstrate the strong interaction between Ru NCs and substrates. The optimized Ru NCs/VN-C3N4 displays a unique porous structure along with plentiful defects, maximizing the exposure of the active sites. As expected, Ru NCs/VN-C3N4 presents a preferable electrocatalytic activity with an overpotential of 8 mV for the HER and 200 mV for the OER at a current density of 10 mA cm−2, along with an ultra-high mass activity of Ru. DFT calculations further substantiate the superior HER and OER performance of Ru NCs/VN-C3N4, and confirm that the introduction of abundant VN effectively modulates the d-band center, intermediate binding energies and structural stability. When integrated into a symmetric electrolyzer, the cell voltage remarkably reduces to 1.488 V with splendid stability in alkaline medium, outperforming nearly all commercial electrocatalysts. This work sheds light on a novel avenue for the rational design of new-generation bifunctional electrocatalysts to promote the popularization of the hydrogen economy. [ABSTRACT FROM AUTHOR]

A general electrocatalyst design for water splitting through generating oxygen vacancies in bimetallic layered double hydroxides by using carbon nitride is proposed. The excellent OER activity of the achieved bimetallic layered double hydroxides is attributed to oxygen vacancies, which reduce the energy barrier of the rate-determining step. [ABSTRACT FROM AUTHOR]

The insufficient catalytic activity of single-atom catalysts for reactions involving multiple intermediates fuels the ongoing research on dual atomic site catalysts (DACs). Herein, we construct a Zn–Y dual single-atom catalyst featuring a ZnY–N6 configuration (ZnY–DACs/NC) with Zn–Y interactions by using a host–guest strategy, which was confirmed by material characterization results. Electron spinning resonance and density-functional theory investigation reveal that ZnY–DACs/NC can generate hydroxyl radicals on the adjacent Zn and Y atoms with an optimal distance under H2O2, which indexing synergistic effects between the adjacent Zn and Y atoms. The colorimetric sensing strategy for hydroquinone well evaluates the outstanding peroxidase-like activity of Zn–Y–DACs/NC. The successful construction of dual single-atom catalysts containing rare-earth metals with synergistic effects showed a promising future for their application in catalysis. [ABSTRACT FROM AUTHOR]

Cobalt phthalocyanine (CoPc)-modified two-dimensional alpha-cobalt hydroxide (α-Co(OH)2) catalysts exhibited excellent electrochemical performance for the reduction of CO2 to CO. The faradaic efficiency (FE) and current density reached 98.4% and 22.4 mA cm−2, respectively. Due to the strong interaction between the metal active sites and the support, the 4.1%-CoPc/α-Co(OH)2 complex displayed a favorable electron density configuration, efficient charge transfer and a large electrochemical surface area. [ABSTRACT FROM AUTHOR]

Heteroatom doping is an efficacious strategy for electronic structure modulation and intrinsic activity adjustment, but the mechanisms accounting for activity enhancement remain controversial. Herein, a controllable self-assembly strategy is applied to manufacture atomically dispersed Fe–N4–O1 anchored N-doped porous carbon. The Fe–N4–O1 active sites possess a coordination number of 5, which exhibit splendid catalytic activity compared with Fe–N4 sites. The oxygen atoms on Fe–N4–O1 sites can not only modulate the adsorption free energy of benzylamine molecules, but also directly oxidize the adsorbed benzylamine molecule to the corresponding imine, thereby promoting the oxidative coupling process of benzylamine. The Fe–N4–O1 coordination, high atomic Fe loading density and huge specific surface area are proven to be three decisive factors affecting the overall activity. Moreover, a possible reaction mechanism involving dual Fe–N4–O1 oxidative and Fe–N4 reactive oxygen species pathways is proposed, which affords guidance for high-efficiency catalyst design toward oxidation-related reactions. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries show great promise to serve as high-energy-density energy storage devices. Nevertheless, the practical applications of Li–S batteries are significantly limited by the shuttle effect and sluggish sulfur redox reaction (SROR) kinetics. Herein, an ingenious urea-mediated pyrolysis strategy is for the first time reported to obtain well-defined atomically distributed asymmetrical five-coordinated Co–N5 moieties anchored on nitrogen-rich (30.0 at%) doped carbon (CoN5 SA/NC) as a highly efficient SROR electrocatalyst. CoN5 SA/NC with a high atomically distributed Co loading (2.12 wt%) effectively catalyzes the liquid–liquid and liquid–solid conversions of lithium polysulfides greatly accelerating the SROR kinetics. When CoN5 SA/NC is served as a coating layer for the separator, the Li–S battery exhibits outstanding capacity properties (1060 mA h g−1 at 1C and 922 mA h g−1 at 2C) and superior cycling stability (ultralow decay of 0.033% per cycle at 3C for 1600 cycles). An ultrahigh areal capacity of 7.25 mA h cm−2 can be acquired for the CoN5 SA/NC based Li–S battery even with a high sulfur loading of 6.5 mg cm−2. Obviously, the asymmetrical single-atom site engineering strategy demonstrates great potential for practical applications of advanced metal–S batteries. [ABSTRACT FROM AUTHOR]

Bipyridine-containing covalent triazine framework (CTF-Bpy) was used to prove that the single site distribution of Co2+ was possible. The Co2+-loaded CTF-Bpy-Co produced 120 μmol CO with a selectivity of 83.8% over 10 h of irradiation (>420 nm). This work highlights the promising potential of single metal sites loaded with CTFs for photocatalytic CO2 reduction. [ABSTRACT FROM AUTHOR]

Bipyridine-containing covalent triazine framework (CTF-Bpy) was used to prove that the single site distribution of Co2+ was possible. The Co2+-loaded CTF-Bpy-Co produced 120 μmol CO with a selectivity of 83.8% over 10 h of irradiation (>420 nm). This work highlights the promising potential of single metal sites loaded with CTFs for photocatalytic CO2 reduction. [ABSTRACT FROM AUTHOR]

High-content atomically distributed W(V , VI) coordinated with O atoms as WO2 moieties anchored on FeCo layered double hydroxide (FeCo LDH) nanosheets in the structure of SAC W–FeCo LDH is obtained by a facile coprecipitation method, and it presented clearly enhanced stable OER electrocatalytic activity. [ABSTRACT FROM AUTHOR]

Developing highly stable and efficient catalysts for the oxygen reduction reaction is important for the long-term operation of proton exchange membrane fuel cells. Herein, combined with the impregnation method, chains of N-doped carbon spheres with abundant pores synthesized by a simple and versatile nanoemulsion assembly strategy have been used to prepare platinum catalysts (Pt-PC-300) via pore confinement and anchoring effect, which enhances the interaction between the metal and the carbon support and thus hinders the metal agglomeration and fall off during the catalytic process. The structure and composition of the materials were characterized by HRTEM, XRD, BET, TEM, SEM, XAS and XPS. Under acidic conditions, Pt-PC-300 showed better catalytic performance in oxygen reduction reaction (ORR) than Pt supported by carbon (XC-72) and commercial Pt/C. Specifically, the Pt-PC-300 catalyst exhibited a similar half-wave potential but much better stability in comparison with the commercial Pt/C because of the pore-confined structure and anchoring effect, the synergy of which provides a new way to develop stable ORR catalysts. [ABSTRACT FROM AUTHOR]

The porous structure is essential for non-precious metal catalysts (NPMCs) to achieve high utilization of active sites and efficient mass transfer in proton exchange membrane fuel cells (PEMFCs). Here, submicron Fe–N–C catalyst particles with three representative types of micropore/mesopore distributions are prepared to investigate the effects of the spatial porosity of the catalyst on fuel cell performance. A microwave detection method is used to monitor the water saturation in the catalyst layer. The structure of the mesoporous surface/microporous core is demonstrated to be the optimal spatial porosity, and the related Fe–N–C catalyst achieves a high PEMFC power density of 1.08 W cm−2 under only 1.5 bar H2–O2. By comparison with fully microporous and fully mesoporous particles, it is found that the mesoporous surface has advantages in improving the number, accessibility, and utilization of active sites, while the microporous core enables the catalyst to avoid the core flooding that occurs in fully mesoporous particles. This study identifies the optimal porosity of NPMCs and proposed a microwave detection method to analyze the water saturation in the electrodes. [ABSTRACT FROM AUTHOR]

The widespread use of high-power LEDs has driven higher requirements for the thermal stability of luminescent materials. Here, we propose an effective synthesis strategy to achieve excellent performances of yellow-emitting phosphors LiZnPO4:xMn2+ through modulating the contents of lattice defects. For the samples prepared in air, the characteristic transitions of Mn2+ ions are observed and the photoluminescent intensity becomes stronger with the increasing temperature until reaching a maximum at 200 °C. Based on electron paramagnetic resonance and defect formation energy, oxygen vacancies are responsible for the self-reduction process from Mn4+ to Mn2+ ions and anti-thermal quenching. The corresponding deep trap levels release captured electrons under thermal stimulus to the conduction band minimum, which non-radiatively relax to the lowest excited state and then withdraw back to the ground state to compensate for the luminous loss. Then, the oxygen vacancy content is optimized by a reducing atmosphere, and the high-temperature behaviours of the targeted phosphor are improved, which further verifies the positive response of properties to defect control. Finally, a fabricated WLED exhibits a good color rendering index (Ra = 89.4), demonstrating the prominent application potential of the as-prepared sample. This study opens up a new gateway for exploring novel anti-TQ optical functional materials, by virtue of the subjective structure design in self-reduction systems. [ABSTRACT FROM AUTHOR]

Pursuing highly active and stable bifunctional electrocatalysts for the hydrogen/oxygen evolution reaction (HER/OER) is significantly important for overall water splitting. Herein, we prepare an electrocatalyst of ultra-small Ru nanoparticles embedded on Fe–Ni(OH)2 nanosheets in situ grown on a Ni foam (RuFe@NF) by a one-pot room temperature immersion method. The RuFe@NF only needs an overpotential of 28 mV to attain 10 mA cm−2 towards the HER and an overpotential of 265 mV to deliver 50 mA cm−2 for the OER in 1 M KOH solution. When RuFe@NF is used as both the cathode and anode for an overall water splitting electrolytic cell, it exhibits a relatively low cell voltage of 1.54 V to obtain 10 mA cm−2. Impressively, the RuFe@NF based electrolytic cell exhibits ultra-long stability over 680 hours at 10 mA cm−2 and even at larger current density up to 100 mA cm−2, which is obviously superior to the noble "Pt/C‖IrO2" couple (i.e., 180 mV voltage increase at 50 mA cm−2 after 36 h), ranking the top among the water splitting catalysts previously reported thus far. The integrated electrode possesses different highly active HER and OER sites and a robust in situ network structure, which collectively improves the electron transport and therefore achieves high activity and stability of the RuFe@NF at an elevated current density. This work offers an alternative bifunctional electrocatalyst, which can be widely extended to large-scale water splitting technology. [ABSTRACT FROM AUTHOR]

Herein, we report a post-assembly strategy by growing bimetallic Co/Zn zeolitic imidazolate frameworks (BIMZIF) on the surface of customized Mo metal–organic frameworks (MOFs) (Mo-MOFs) to prepare core–shell structured Mo-MOF@BIMZIF, which results in a porous Co–MoO2 polyhedral nanocage (Co–MoO2-NC) structure and abundant Co–Mo–O active sites after high temperature pyrolysis. Co–MoO2-NC-900 which was obtained by pyrolysis at 900 °C displays a low overpotential (370 mV) for the oxygen evolution reaction (OER) and a half-wave potential (E1/2 ≈ 0.89 V) for the oxygen reduction reaction (ORR), exhibiting bifunctional features. A Zn–air battery with Co–MoO2-NC-900 shows a high power density of 176.5 mW cm−2 at 217.1 mA cm−2, which is better than that of reference Pt/C + Ir/C electrocatalysts, and is capable of exhibiting a smaller discharge–charge overpotential (0.85 V) and excellent stability (1145 h). Density functional theory calculations and experiments reveal that the structure and electron transfer between the Co and MoO2 components reduce the free energy of the intermediates, resulting in bifunctional electrocatalytic activity. [ABSTRACT FROM AUTHOR]

The sluggish redox conversion of sulfur species, especially under high sulfur loading, low-temperature, and low electrolyte/sulfur (E/S) ratio conditions, aggravates the shuttle effect that severely deteriorates the electrochemical performance of Li–S batteries. Herein, alloying metallic Ni with Fe increases the Ni–Ni(Fe) bond length and reduces the coordination number of Ni, realizing the upshift of the d-band center towards the Fermi level, and thus regulates sulfur species adsorbability to a rational level to accelerate their catalytic conversion. As a consequence, the Li–S batteries with Ni3Fe-modified separators exhibit superior rate performances (800 and 645 mA h g−1 at 10 and 15C, respectively) and excellent cycling stability (capacity decay of 0.05% per cycle over 800 cycles at 2.0C). Meanwhile, the stable operation of high areal capacity Li–S batteries under a high sulfur loading of 30 mg cm−2 and a low electrolyte/sulfur ratio of ∼7 µL mg−1 is realized. Besides, benefitting from the enhanced kinetics, the battery can work well at −10 °C, which is rarely achieved by conventional Li–S batteries. Our work provides a promising strategy for designing high-activity electrocatalysts for high-performance and low-temperature Li–S batteries. [ABSTRACT FROM AUTHOR]

A Cu–N-doped carbon nanotube with an unsaturated coordination Cu atom (Cu–N3) was fabricated and it exhibited over 90% CO faradaic efficiency (FE) in a wide potential range from −0.42 to −0.92 V. The maximum CO FE can reach 98.7% with a high CO partial current density of 234.3 mA cm−2 in a flow cell. Theoretical calculations elucidated that the Cu–N3 site facilitated the formation of COOH*, thereby accelerating the CO2 electrochemical reduction. [ABSTRACT FROM AUTHOR]

1T-phase molybdenum disulphide (MoS2) is considered to be one of the most promising candidates to substitute noble metals in the hydrogen evolution reaction (HER). Fabricating single layer 1T-phase MoS2 with abundant sulfur vacancies as well as good stability to further enhance catalytic performance remains a challenge. Herein, we develop an efficient in situ TMA cation ((CH3)4N+) intercalation method to produce 1T-phase MoS2. The obtained MoS2 nanosheets comprise about 81% 1T-phase and abundant sulfur vacancies (>12%), as verified by aberration-corrected high-angle annular dark field scanning transmission electron microscopy (AC-HAADF-STEM), X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS), etc. In addition, the surface of as-prepared ST-MoS2 is negatively charged, making it very stable in aqueous solution. The as-prepared ST-MoS2 exhibits excellent electrochemical HER performance with a low over-potential and a small Tafel slope as well as superior cycling stability. Furthermore, it is an excellent co-catalyst when coupled with CdS nanowires to form a CdS/ST-MoS2 heterojunction photocatalyst for the HER under visible light irradiation. It achieves a maximum H2 production rate and apparent quantum efficiency (AQE) of approximately 1187 μmol mg−1 h−1 and 73.4%, respectively, which are significantly higher than those of reported CdS/MoS2 photocatalysts. [ABSTRACT FROM AUTHOR]

P2-type Na2/3Ni1/3Mn2/3O2 is one of the most promising cathode candidates for sodium-ion batteries due to its high specific capacity and high working voltage. However, a detrimental P2–O2 phase transition usually occurs at a high voltage (>4.2 V) leading to poor cycle stability. Herein, we propose to mitigate this critical issue through a controlled F−/Ca2+ dual-doping strategy with CaF2 as a dopant. The divalent Ca2+ ion doped in the Na layer stabilizes the layered structure at a high voltage when excessive Na+ is extracted. The more electronegative F− ion forms a stronger transition metal (TM)–F bond and reduces the electrostatic repulsion between the oxygen layers impeding the gliding of TMO2 layers. The Ca2+/F− co-doping successfully suppresses the unfavorable P2–O2 phase transition, and significantly improves the structural stability and cycling performance (27.1% vs. 87.2% after 500 cycles at 1C). Furthermore, density functional theory calculations combined with experimental tests reveal that the incorporation of Ca2+ and F− in Na sites and O sites facilitates the electronic and ionic conductivity owing to Na+/vacancy disordering, which enhances the high-rate capability. This study provides some insights into the design of long-life and high-rate cathode materials for sodium-ion batteries. [ABSTRACT FROM AUTHOR]

The Li–O2 battery is recognized as one of the most promising energy storage devices for next-generation automotive batteries due to its extremely high theoretical energy density. The design and preparation of highly active and durable catalysts for the air cathode are vital to make its practical application possible. Herein, we present a well-designed graphene-based cathode material in which single Co atoms are coordinated with N in three-dimensional reduced graphene oxide and Ru clusters are anchored on the surface of the material. The battery with our optimal sample (RuNC/CoSA–3DNG) as the cathode exhibits a discharge capacity of 25 632 mA h g−1 (at 100 mA g−1) and superior cycling stability for 300 cycles. The greatly enhanced performance is attributable to the highly active Co–N–C sites and the electron-deficient Ru nanoclusters, which facilitate increased ORR/OER activity and higher Ru atomic utilization efficiency. This work may provide new inspiration for designing highly efficient catalysts for Li–O2 batteries. [ABSTRACT FROM AUTHOR]

Using solar energy to realize CO2 reduction and benzylamine oxidation is of great importance. Here, we design Zn-Bi2WO6 microflowers catalyst, which can simultaneously reduce CO2 to CO and oxidize benzylamine to N-benzylbenzaldimine with high activities and selectivities in a simple photocatalytic system. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate the highly efficient photocatalytic sulfide oxidation reaction under mild conditions, i.e. in air, at room temperature and in the absence of a sacrificial reagent, co-catalyst or redox mediator, by using ultrathin C,N-TiO2 nanosheets as a photocatalyst. [ABSTRACT FROM AUTHOR]

Monomeric active species are very interesting in heterogeneous catalysis. In this work, we proposed a method to prepare VOx–NbOy@C catalysts, which involve the one-pot hydrothermal synthesis of inorganic/organic hybrid materials containing V/Nb followed by thermal treatment under a reducing atmosphere. The prepared catalysts were characterized using different techniques, such as high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine structure spectroscopy. It was shown that monomeric VOx species were dispersed homogeneously in the catalysts. The VOx–NbOy@C catalysts displayed high performance in the aerobic oxidative dehydrogenation of N-heterocycles to aromatic heterocycles. It was demonstrated that the selectivity of reaction over the catalyst with a very small amount of V (0.07 wt%) was much higher than that over the NbOy@C, and the catalyst also exhibited excellent stability in the reaction. The detailed study indicated that monomeric VO2 species were the most effective for promoting the reaction. [ABSTRACT FROM AUTHOR]

Numerous molecular ferroelectrics having excellent properties even comparable to inorganic ones, which usually contain heavy or toxic metals, have been developed recently. Hopefully, they can be used as substitutes for the well-known organic ferroelectric polymers (P(VDF-TrFE)) with huge coercive fields and poor spontaneous polarization for various applications. However, the bottleneck for practical applications, i.e., the preparation of high-quality thin films and high resolution device arrays with a desired crystallographic orientation for memory switching, still remains. In this study, large-area micro device arrays of molecular ferroelectrics with highly-crystalline or even single-crystalline films are intentionally self-assembled on electrodes or within electrode gaps using a solution processing technique, including the molecular ferroelectrics for which it is usually difficult to make thin films. The as-grown air-stable memory micro arrays with an optimum crystallographic orientation can exhibit excellent non-volatile memory performance with a smaller operation voltage of <5 V. These attributes can pave the way for molecular ferroelectrics to become a promising candidate for applications including flexible memories and circuits. [ABSTRACT FROM AUTHOR]

Development of robust and highly active electrocatalysts for the oxygen evolution reaction (OER) is of significance for next-generation renewable energy storage and conversion. Herein, for the first time, we report pyrite-type iron nickel monophosphosulfide (Ni1−xFexPS, x = 0, 0.1, 0.15, 0.2) electrocatalysts with exceptional OER efficiency and stability under alkaline conditions. Ni0.85Fe0.15PS/NF exhibits a considerably low overpotential of 251 (314) mV at 10 (100) mA cm−2 with a Tafel slope of 34 mV dec−1, together with remarkable stability. Moderate Fe regulation in NiPS (Ni0.85Fe0.15PS) is found to stimulate the activation of high-valence-state Ni/Fe oxyhydroxides during the irreversible surface reconstructions that form disordered MOOH@MxSOy@MxPOy surfaces under OER conditions, as is established by microstructural observations, surface-sensitive X-ray photoelectron spectroscopy, Raman spectroscopy and X-ray absorption spectroscopy. DFT calculations show that the catalytic sites formed by Fe doping are more nucleophilic than the Ni sites and thus more OER active, due to a facile Fe(II) → Fe(III) oxidation state change for Fe. Meanwhile, overly stable OER surface species are not formed, as Fe in oxidation states higher than Fe(III) is not favorable, which leads to a lower barrier for the rate-limiting OER step than that for the Ni site. The present results shed light on the design and development of high-performance electrocatalysts in ternary metal monophosphosulfides, as well as providing a fundamental understanding of their intrinsic active sites. [ABSTRACT FROM AUTHOR]

Identification of active sites in the electrochemical hydrogen evolution reaction (HER) under realistic conditions is critical to water electrolysis for future sustainable energy applications. Herein, we rationally designed an isolated single-atom Ru-modified FeP as a model catalyst with enhanced HER performance, which displayed an overpotential of 62 mV at a current density of 10 mA cm−2 and a small Tafel slope of 45 mV dec−1. Importantly, through operando X-ray absorption spectroscopy measurements together with density functional theory calculations, a synergistic effect was discovered between the monodispersed metal atoms and the phosphide substrate. We found that the bond-length-extended isolated Ru(+3)–P4–Fe species under catalytic conditions serve as the boosted active sites during the HER, leading to charge redistribution at the atomic interface of the catalyst, meanwhile improving the H adsorption and H2 desorption behavior, and further promoting the HER kinetics. This work gives new viewpoints for the exploration of highly active transition-metal-phosphide-based HER catalysts by refinement of the atomic and electronic structure. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate for the first time the construction of hollow structural Co-MOF-74, whose shell is as thin as ∼50 nm and assembled by nanoparticles ranging from 8 to 18 nm. It exhibits high performance for the photocatalytic oxidation of thioanisole and thermocatalytic cyanosilylation of aldehydes. [ABSTRACT FROM AUTHOR]

The macro–meso–microporous and defective metal–organic framework constructed by transition metal Zn and 2,2′-bipyridine-5,5′-carboxylate was synthesized in CO2-expanded solvent. It shows high photocatalytic activity and selectivity for the oxidation of amines to imines under mild conditions, i.e., air as an oxidant, room temperature, and involving no photosensitizer or cocatalyst. [ABSTRACT FROM AUTHOR]

Isolated single-atom site metals/nitrogen-doped porous carbon (ISAS M/NPC, M = Fe, Co, Ni) catalysts are successfully prepared by a top–down polymerization-pyrolysis-etching-activation (PPEA) strategy, which uses dopamine as the precursor. Due to the isolated single atom Fe active sites and porous structure, the ISAS Fe/NPC catalyst displays a high benzene conversion up to 42.6% and nearly 100% phenol selectivity. [ABSTRACT FROM AUTHOR]

Here we demonstrate that the utilization of 2,4,6-tris(4-pyridyl)pyridine (tpy) for metal–organic framework modification can greatly improve the photocatalytic performance for CO2 reduction. The electron-donating nature of tpy enables the charge transfer effect, which induces strong CO2 binding affinity, facilitates *COOH formation and promotes CO2-to-CO conversion. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials have abundant sources but are difficult to use directly as a support for single atom catalysts (SACs) due to the lack of strong anchoring forces to restrict the movement and aggregation of metal atoms during the high-temperature heat treatment. Herein, we report a "self-catalysis" method for the synthesis of ferrous metal single-atom catalysts (SACs) FM–N–C (FM = Fe, Co, and Ni) with ∼2 wt% metal loadings on a carbon black support. The combination of experimental and theoretical evidence reveals a self-catalytic process from FM atoms to FM–N4 species, which involves (1) the adsorption of FM ions on the surface-oxidized carbon nanoparticles via oxygen coordination bonds (FM–O); (2) the catalytic decomposition of ammonia to nitrogen radicals on the FM atoms; (3) the replacement of coordinating oxygen with nitrogen. The precoordination of FM with oxygen is the key to the synthesis and reduces the energy barrier of ammonia decomposition and nitrogen bonding to the FM atoms. Thus, the formation of the FM–N4 species at a mild temperature of 600 °C is enabled. The as-synthesized FM–N–C SACs exhibit high catalytic activities towards O2 and/or CO2 reduction reactions. In contrast to the metal–organic framework-based SACs in which the MOF support significantly changes in size and weight, the self-catalysis technique is "minimally invasive" to the carbon support, thus benefiting the structural design of SACs by taking advantage of the abundant morphologies of the carbon nanomaterials. [ABSTRACT FROM AUTHOR]