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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]

Li4Ti5O12 (LTO) attracts great interest due to the "zero strain" during cycles but the poor electronic and ionic conductivity critically impede the practical application. Herein, we report a synergy strategy of tuning localized electrons to shift Fermi level and band gap by Mg/Zr co‐doping and oxygen vacancy incorporation, which significantly improves Li+ and electronic transport. More importantly, the intrinsic synergistic mechanism has been revealed by neutron diffraction, X‐ray absorption spectra, and first‐principles calculations. The "elastic effect" of lattice induced by Mg/Zr co‐doping allows LTO to accommodate more oxygen vacancies to a certain degree without a severe lattice distortion, which largely improves the electronic conductivity. Mg/Zr co‐doping and oxygen vacancy incorporation effectively enhanced the dynamic characteristics of LTO electrode, achieving the excellent rate performance (90 mAh/g at 20C) and cycle stability (96.9% after 500 cycles at 10C). First‐principles calculations confirm Fermi level shifts to the conduction band, and the band gap becomes narrowed due to the synergistic modulation, and the intrinsic mechanism of the enhanced electronic and Li‐ion conductivity is clarified. This study offers some insights into achieving the fast Li+ insertion/extraction by tuning the crystal and electronic structure with lattice doping and oxygen vacancy engineering. [ABSTRACT FROM AUTHOR]

Highlights: Precisely located S doping of atomic Fe-N4 in Fe(N3)(N–C–S) motif was realized. This S doping renders weakened *OH binding and faster charge transfer on Fe-N4. Fe-NSC showed excellent oxygen reduction reaction performance with onset potential ~ 1.09 V and half-wave potential ~ 0.92 V.Immobilizing metal atoms by multiple nitrogen atoms has triggered exceptional catalytic activity toward many critical electrochemical reactions due to their merits of highly unsaturated coordination and strong metal-substrate interaction. Herein, atomically dispersed Fe-NC material with precise sulfur modification to Fe periphery (termed as Fe-NSC) was synthesized, X-ray absorption near edge structure analysis confirmed the central Fe atom being stabilized in a specific configuration of Fe(N3)(N–C–S). By enabling precisely localized S doping, the electronic structure of Fe-N4 moiety could be mediated, leading to the beneficial adjustment of absorption/desorption properties of reactant/intermediate on Fe center. Density functional theory simulation suggested that more negative charge density would be localized over Fe-N4 moiety after S doping, allowing weakened binding capability to *OH intermediates and faster charge transfer from Fe center to O species. Electrochemical measurements revealed that the Fe-NSC sample exhibited significantly enhanced oxygen reduction reaction performance compared to the S-free Fe-NC material (termed as Fe-NC), showing an excellent onset potential of 1.09 V and half-wave potential of 0.92 V in 0.1 M KOH. Our work may enlighten relevant studies regarding to accessing improvement on the catalytic performance of atomically dispersed M-NC materials by managing precisely tuned local environments of M-Nx moiety. [ABSTRACT FROM AUTHOR]

Atomically dispersed metal-N-C structures are efficient active sites for catalyzing benzene oxidation reaction (BOR). However, the roles of N and C atoms are still unclear. We report a polymerization-regulated pyrolysis strategy for synthesizing single-atom Fe-based catalysts, and present a systematic study on the coordination effect of Fe-NxCy catalytic sites in BOR. The special coordination environment of single-atom Fe sites brings a surprising discovery: Fe atoms anchored by four-coordinating N atoms exhibit the highest BOR performance with benzene conversion of 78.4% and phenol selectivity of 100%. Upon replacing coordinated N atoms by one or two C atoms, the BOR activities decrease gradually. Theoretical calculations demonstrate the coordination pattern influences not only the structure and electronic features, but also the catalytic reaction pathway and the formation of key oxidative species. The increase of Fe-N coordination number facilitates the generation and activation of the crucial intermediate O=Fe=O species, thereby enhancing the BOR activity. Atomically dispersed metal-N-C are efficient active site for benzene oxidation but the roles of N and C atoms are still unclear. Here the authors report a highly-active single-atom Fe-based benzene oxidation catalyst and provide deep insights into the structure-activity relationship at atomic level. [ABSTRACT FROM AUTHOR]

[Display omitted] • The K-mediated ultrasmall Ru nanoclusters show excellent NH3 synthesis activity. • Avoiding hydrogen poisoning on ultrasmall Ru nanoclusters through K mediation. • The addition of K could mediate the H-spillover and d-band center. • K addition significantly affects the electronic structure of Ru and oxygen vacancies. The effects of promoters on Ru nanoparticles (≥2 nm) catalysts for NH 3 synthesis have been extensively elaborated, but their roles on ultrasmall Ru nanoclusters (NCs, 1–2 nm) remain largely unknown and need to be further uncovered. Herein, a series of K-promoted MgO supported Ru NCs were synthesized and investigated for NH 3 synthesis. The addition of 5wt.%K onto Ru/MgO NCs leads to a significantly high NH 3 synthesis rate of 21.7 mmol NH3 g cat −1h−1 at 400 °C and 0.2 MPa, close to the thermodynamic equilibrium. Out studies reveal that anchoring K onto Ru NCs can increase the electron density and cause an upshift of the d -band center of Ru entities. Moreover, the addition of K regulates the hydrogen affinity and accelerates the migration of hydrogen from the Ru NCs surface to MgO support, which is crucial in avoiding the hydrogen poisoning effect on Ru NCs. With the synergistic effect of the Ru NCs sites bridged by H-spillover, makes the K-mediated Ru/MgO NCs catalysts efficient for NH 3 synthesis at mild conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • A class of Ru-Co single-atom alloy catalysts (marked as Ru x Co 1 SAA, x stands for Ru/Co molar ratio) were prepared. • The electronic structure of Ru x Co 1 SAA could be effectively tuned by regulating the Ru/Co molar ratio. • A moderate ratio of Ru/Co (1.7:1) favors superior NH 3 synthesis rate. • The excess Ru destroys the SAA structure, resulting in the diminution of SAA advantages. Rational design of efficient catalysts for ammonia (NH 3) synthesis at mild conditions is of paramount importance for the development of electrolysis driven Haber-Bosch (e HB) process. Ammonia synthesis is a structure sensitive reaction, and any small change of electronic structure could result in dramatic change of catalytic activity, especially for the Ru-based NH 3 synthesis catalysts. Electronic structure modulation of the Ru-based catalysts could provide desirable catalytic activity. Herein, we explore a class of Ru-Co single-atom alloy catalysts (marked as Ru x Co 1 SAA, x stands for Ru/Co molar ratio), in which Co single atoms are located on Ru nanoclusters to form Co-Ru coordination, and then electronic structure of Ru x Co 1 SAA could be effectively tuned by regulating the Ru/Co molar ratio. Our studies show that a moderate ratio of Ru/Co (1.7:1) favors superior NH 3 synthesis rate and low activation energy. Using a suite of elaborate characterizations, we have observed that the outstanding performance over Ru 1.7 Co 1 SAA can be attributed to the electron redistribution between Ru and Co atom, resulting in an upshift of d band center and lowering of work function. However, there is decrease of NH 3 synthesis rate when Ru/Co molar ratio is 2, due to the partial detachment of Ru entities from SAA structure, and the formed individual Ru nanoparticles (NPs) overlay the surface of catalyst. In such a case, N 2 activation behavior over Ru 2 Co 1 is alike that of Ru NPs catalysts. The present study demonstrates that the Ru/Co ratio in SAA structure can effectively regulate the electronic structure of catalyst for NH 3 synthesis rate enhancement. [ABSTRACT FROM AUTHOR]

[Display omitted] • Designing three congeneric Co-N 4 model molecules with recognizable configurations. • Unravelling the structure-induced interfacial activation in CO 2 electroconversion. • Exotic paired tandem electrosynthesis steers value-added conversion of CO 2 to DMC. The recognition of structure-induced interfacial activation in heterogenized molecule catalysts is essential to steer CO 2 value-added electroconversion but remains inadequate. Herein, through designing three congeneric Co-N 4 model molecules (Co-CPY, Co-TAA and Co-PHE) with recognizable steric configurations, we systematically investigated the impact of structure-induced interfacial activation on promoting CO 2 electroconversion. Concretely, the Co-CPY/CNTs, featuring highly planar and conjugated molecules immobilized onto CNTs, delivers an ultra-high current density and enables near-unity Faradaic efficiency for CO 2 electroconversion, exceeding the counterparts. The theoretical and spectrographic findings demonstrate that the Co-CPY/CNTs not only creates the adaptive interfaces with strong communication to greatly expedite electron transfer but also reconstructs the electronic structures of active Co-N 4 units to effectively promote the formation of intermediates. Furthermore, the electroconversion of CO 2 to dimethyl carbonate was reliably performed with a high yield of 96 μmol cm–2 h−1 through paired tandem electrosynthesis, highlighting the superior expansibility of Co-CPY/CNTs. [ABSTRACT FROM AUTHOR]

Nitrate (NO 3 –) is an important raw ingredient for fertilizer, but its conventional synthesis is restricted by high energy consumption and CO 2 emissions. Though there have been some studies on photocatalytic nitrogen oxidation, the production rate of nitrate is undesirable and the excited-state charge-transfer pathway still remains unclear. Herein, we fabricated the V-doped W 18 O 49 nanowires (V- W 18 O 49) for direct nitrate synthesis from N 2 photooxidation. The NO 3 - production rate is as high as 39.85 μmol g−1 h−1 with exceptional catalytic stability and the photosynthetic nitrate fertilizer was employed to promote the growth of crops. Time-resolved spectroscopic results confirmed that the introduction of V doping in V- W 18 O 49 has created new high-efficiency electron-transfer (ET) pathways from the W-O site to the V-dopant under photoirradiation, which leads to an improved π-backdonation process that facilitates nitrogen activation. This newly formed ET channel facilitated efficient charge separation and ultrafast photogenerated carriers transfer, thus overcame the sluggish ET kinetics. [Display omitted] The V-doped W 18 O 49 nanowires were rationally designed and successfully fabricated through a facile solvothermal method. The NO 3 - production rate is as high as 39.85 μmol g−1 h−1 and the photosynthetic nitrate was employed as N-fertilizer. The introduction of V dopants created new high-efficiency electron-transfer (ET) pathways that facilitated the photogenerated carriers transfer. [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]

"Zero-strain" Li 4 Ti 5 O 12 has become one of the most promising anode materials for lithium-ion battery but its low electronic and ionic conductivity lead to the poor rate capability. Herein, the high-rate performance and the cycling stability of Li 4 Ti 5 O 12 have been largely enhanced by replacing Li and Ti with a little amount of Mg and La, respectively. The synergistic modulation mechanism of Mg and La co-doping on the crystal/electronic structure and electrochemical performances has been unveiled. Firstly, Mg and La co-doping enlarges the lattice parameters, unit cell volume and Li1–O bond. These facilitate the lithium-ion migration and enhance the rate capability. Secondly, Ti–O bond is shortened which enhances the structure stability and cyclic performance. Thirdly, the first-principles calculations further confirm that Mg/La co-doping modulates the electronic density of states and decreases the Li+ migration barrier. The polarization and charge transfer impedance are effectively alleviated. Moreover, the diffusion coefficient of lithium ions is further improved because of the reduction of much more Ti3+. At 10C, it delivers a discharge capacity of 107.8mAh/g after 500cyles which reserves 92.2% of the initial capacity. This study provides some insights into optimizing the electrochemical performances of Li 4 Ti 5 O 12 by tuning the crystal and electronic structure with lattice doping. Image 1 [ABSTRACT FROM AUTHOR]

• Mo 2 C/CFP-Act is prepared via continuous cathode polarization technique. • Mo 2 C/CFP-Act is an excellent electrocatalyst for the hydrogen evolution reaction. • Mechanism study unveils the Pt single atom intrinsic role in Mo 2 C/CFP catalysts. Dispersing catalytically active metals as single atoms on supports offer an efficient pathway to minimize amount of precious metals. Although platinum (Pt) is highly active for HER, it is highly desirable to find ways to improve the HER performance and also keeping them stable during catalytic reactions while minimizing the Pt loading. Herein, we report a cathode polarization technique to disperse isolated single Pt atoms on β-Mo 2 C as a catalyst for HER. The isolated Pt atoms partially occupy Mo sites in Mo 2 C lattice by forming Pt-Mo shells, which maximize the utilization ratio of platinum noble metals. The single atoms catalyst Mo 2 C/CFP-Act even exhibited 1.9 and 1.1 times higher current density (@ potential of 0.4 V vs. RHE) than that of Pt NPs catalysts (Mo 2 C/CFP-Pt) after mass normalization in both acidic and alkali solution. Furthermore, DFT calculations demonstrate that Mo 2 C/CFP-Act exhibits favorable ΔG H* for the adsorption and desorption of hydrogen. The high HER activity of the Mo 2 C/CFP-Act catalyst is related to the Mo-Pt center located in Mo 2 C matrix, where the electronic structure of the Mo-Pt centers more efficient in donating electron to the σ* antiorbital of the H 3 O+ molecule. This study sheds new light on the HER catalysis mechanism of isolated metal atoms based on fundamental understanding in molecular governing factors. [ABSTRACT FROM AUTHOR]

Multiferroic BiFe 1- x Zn x O 3 (0 ≤ x ≤ 0.1) powders were synthesized by a hydrothermal method. Structural studies using X-ray diffraction revealed that all samples possessed a rhombohedral R 3 c perovskite structure. Scanning electron microscopy showed that the average grain size decreased slightly with increasing Zn concentration. Fe K -edge and Bi L 3 -edge X-ray absorption fine structure spectra indicated that both the Fe and Bi ions had a +3 valence state in all samples. The local electronic structure of the center atoms was affected by Zn doping. Fourier transform infrared analysis revealed the characteristic vibrations of the obtained BiFe 1- x Zn x O 3 (0 ≤ x ≤ 0.1) samples. Magnetic hysteresis loop measurements indicated a maximum remnant magnetization (M r ) for the x = 0.025 sample, which was primarily a result of the Fe 3+ -O-Zn 2+ anti-ferromagnetic exchange interaction. [ABSTRACT FROM AUTHOR]

Efficiency of the electrocatalysts for hydrogen evolution reaction (HER) strongly depends on their extrinsic physical properties and intrinsic electronic structures. Among various modulation strategies, nanoalloying is an efficient route to regulate the intrinsic activities of HER intermediates. Herein, we develop a facile and universal one-step pyrolyzed method to fabricate bimetallic Ru-based nanoalloy catalysts encapsulated by B/N co-doped graphitic nanotubes (RuM@BCN, M=Ir, Pt, Ag, Co, and Fe) for high-performance alkaline HER. BCN nanotube substrates provide sufficient open channels, porous structures and strong anchoring effect to achieve fast kinetics and high stability. The bimetallic nanoalloying strategy greatly promotes the water dissociation and hydrogen adsorption ability of the electrocatalysts via modulation on their intrinsic electronic structures. Therefore, the as-made RuM@BCN demonstrates varied HER behaviors by alloying metals, in which RuIr@BCN exhibits the highest alkaline HER activity with an overpotential of 23.6 mV at the current density of 10 mA cm−2, outperforming commercial Pt/C. [Display omitted] • A general and facile strategy is developed to fabricate bimetallic RuM@BCN nanotubes. • Alloying Ru and Ir atoms induces electronic structure changes and promotes alkaline HER. • BCN nanotubes show great potentials to embed various Ru-based nanoalloy catalysts. • RuIr@BCN demonstrates an overpotential of 23.6 mV at 10 mA cm− 2 for alkaline HER. [ABSTRACT FROM AUTHOR]

• The stabilization mechanism of single atom Pt 1 -CeO 2 materials was proposed. • The Pt-O-Ce interface distortion balanced the Fermi energy level and charge density. • The interface distortion promoted the adsorption capacity of O 2 and methanol. • The Pt 1 -CeO 2 {100} catalyst exhibits outstanding catalytic efficiency and stability. • The methanol oxidation and surface reconstruction were revealed in an atomic-scale. Exploring thermally robust single atom catalysts (SACs) is of great significance. Here, we develop a universal strategy for stabilizing Pt atoms on the mono-oxygen vacancies of CeO 2 with diverse exposed facets. The stabilization mechanism was proposed that the formed Pt-O-Ce interface will be taken into distortion spontaneously to keep thermodynamics stable through strong metal-support interactions. The highest degree of Pt-O-Ce distortion is achieved over Pt1-CeO2{100} material, which exhibits exceptional efficiency and thermal stability for oxygenated hydrocarbon removal. The enhanced adsorption capacity of O2 and methanol confirmed in the distortion interface is seen as another crucial reason for improving the stability of SACs. Methanol oxidation on Pt1-CeO2{100} obeys the L-H mechanism under relatively low temperature and then goes through to the MVK mechanism with temperature increasing. We believe that these results would bring new opportunities in the fabrication of SACs and applications of them in thermal reactions. [ABSTRACT FROM AUTHOR]