Efficient Interfacial Sites between Metallic and Oxidized Cobalt for Propene Hydroformylation.

Currently, the hydroformylation of short olefins is operated almost exclusively by using Rh catalysts. Considering the high cost and scarcity of rhodium resources, it is important to develop non-noble metal catalysts toward hydroformylation. Herein, we report an efficient cobalt-based catalyst rich in interfacial sites between metallic and oxidized cobalt species for the hydroformylation of short olefin, propene, under a moderate syngas pressure. The catalyst exhibited a high specific activity of 252 mol molCo-1 h-1 in toluene under 2 bar of propene and 40 bar of CO/H2 mixed gas (CO/H2 = 1:1) at 160 °C. According to mechanistic studies, the interface of metallic and oxidized cobalt species promoted the adsorption of CO and propene. Moreover, the interfacial sites lowered the energy barrier for CO* hydrogenation and C-C coupling compared with metallic cobalt.

Cooperative Ni(Co)-Ru-P Sites Activate Dehydrogenation for Hydrazine Oxidation Assisting Self-powered H2 Production.

Water electrolysis for H2 production is restricted by the sluggish oxygen evolution reaction (OER). Using the thermodynamically more favorable hydrazine oxidation reaction (HzOR) to replace OER has attracted ever-growing attention. Herein, we report a twisted NiCoP nanowire array immobilized with Ru single atoms (Ru1 -NiCoP) as superior bifunctional electrocatalyst toward both HzOR and hydrogen evolution reaction (HER), realizing an ultralow working potential of -60 mV and overpotential of 32 mV for a current density of 10 mA cm-2 , respectively. Inspiringly, two-electrode electrolyzer based on overall hydrazine splitting (OHzS) demonstrates outstanding activity with a record-high current density of 522 mA cm-2 at cell voltage of 0.3 V. DFT calculations elucidate the cooperative Ni(Co)-Ru-P sites in Ru1 -NiCoP optimize H* adsorption, and enhance adsorption of *N2 H2 to significantly lower the energy barrier for hydrazine dehydrogenation. Moreover, a self-powered H2 production system utilizing OHzS device driven by direct hydrazine fuel cell (DHzFC) achieve a satisfactory rate of 24.0 mol h-1 m-2 .

Synergistic Modulation at Atomically Dispersed Fe/Au Interface for Selective CO2 Electroreduction.

The electrocatalytic carbon dioxide reduction reaction (CO2RR) offers an attractive route to fuels and feedstocks from renewable energy. Gold is active for the electrochemical CO2RR to CO, while the competing hydrogen evolution reaction is unavoidable. Here, we report a synergistic strategy, via introducing atomically dispersed Fe to tune the electronic structure of the Au nanoparticle, to improve the CO selectivity. By using operando X-ray absorption and infrared spectroscopies, we reveal the dynamic structural evolution and the adsorption of reactant intermediates at the single-atom Fe1/Au interface. During the reaction, the interaction between Fe and Au atoms becomes stronger, and the Fe1/Au synergies affect the adsorption of reaction intermediates, thus improving the selectivity of CO up to 96.3% with a mass activity of 399 mA mg-1. These results highlight the significant importance of synergistic modulation for advancing the single-atom decorated nanoparticle catalysis.

Synergistic Catalysis at the Ni/ZrO2-x Interface toward Low-Temperature CO2 Methanation.

The CO2 methanation reaction, which achieves the carbon cycle and gains value-added chemicals, has attracted much attention, but the design and exploitation of highly active catalysts remain a big challenge. Herein, zirconium dioxide-supported Ni catalysts toward low-temperature CO2 methanation are obtained via structural topological transformation of NiZrAl-layered double hydroxide (LDH) precursors, which have the feature of an interfacial structure (Ni-O-Zr3+-Vö) between Ni nanoparticles and ZrO2-x support (0 < x < 1). The optimized catalyst (Ni/ZrO2-x-S2) exhibits exceptional CO2 conversion (∼72%) at a temperature as low as 230 °C with a ∼100% selectivity to CH4, without obvious catalyst deactivation within a 110 h reaction at a high gas hourly space velocity of 30,000 mL·g-1·h-1. Markedly, the space-time yield of CH4 reaches up to ∼0.17 molCH4·gcat-1·h-1, which is superior to previously reported Ni catalysts evaluated under similar reaction conditions. Both in situ/operando investigations (diffuse reflectance infrared Fourier transform spectroscopy and X-ray absorption fine structure) and catalytic evaluations substantiate the interfacial synergistic catalysis at the Ni/ZrO2-x interface: the Zr3+-Vö facilitates the activation adsorption of CO2, while the H2 molecule experiences dissociation at the metallic Ni sites. This work demonstrates that the metal-support interface effect plays a key role in improving the catalytic behavior toward CO2 methanation, which can be extended to other high-performance heterogeneous catalysts toward structure-sensitive systems.

Conformational control and regulation of the pseudokinase KSR via small molecule binding interactions.

Pseudokinases often operate through functionally related enzymes and receptors. A prime example is the pseudokinase KSR (Kinase Suppressor of RAS), which can act as both an amplifier and inhibitor of members in the RAS-MAPK (Mitogen Activated Protein Kinase) signaling pathway. KSR is structurally related to the active RAF kinases over multiple domains; moreover, the pseudokinase domain of KSR forms physical and regulatory complexes with both RAF and MEK through distinct interfaces. Characterization of small molecule interactions on KSR has been used to uncover novel chemical tools and understand the mechanism of action of clinical drugs. Here, we elaborate on assays and structural methods for measuring binding at orthosteric and interfacial binding sites on KSR. These distinct small molecule pockets provide therapeutic paths for targeting KSR1 and KSR2 pseudokinases in disease, including in RAS and RAF mutant cancers.

Ga-Promoted CuCo-Based Catalysts for Efficient CO2 Hydrogenation to Ethanol: The Key Synergistic Role of Cu-CoGaOx Interfacial Sites.

Currently, direct catalytic CO2 hydrogenation to produce ethanol is an effective and feasible way for the resource utilization of CO2. However, constructing non-precious metal catalysts with satisfactory activity and desirable ethanol selectivity remains a huge challenge. Herein, we reported gallium-promoted CuCo-based catalysts derived from single-source Cu-Co-Ga-Al layered double hydroxide precursors. It was manifested that the introduction of Ga species could strengthen strong interactions between Cu and Co oxide species, thereby modifying their electronic structures and thus facilitating the formation of abundant metal-oxide interfaces (i.e., Cu0/Cu+-CoGaOx interfaces). Notably, the as-constructed Cu-CoGa catalyst with a Ga:Co molar ratio of 0.4 exhibited a high ethanol selectivity of 23.8% at a 17.8% conversion, along with a high space-time yield of 1.35 mmolEtOH·gcat-1·h-1 for ethanol under mild reaction conditions (i.e., 220 °C, 3 MPa pressure), which outperformed most non-noble metal-based catalysts previously reported. According to the comprehensive structural characterizations and in situ diffuse reflectance infrared Fourier transform spectra of CO2/CO adsorption and CO2 hydrogenation, it was unambiguously revealed that CHx could be formed at oxygen vacancies of defective CoGaOx species, while CO could be stabilized by Cu+ species, and thus the catalytic synergistic role of Cu0/Cu+-CoGaOx interfacial sites promoted the generation of CHx and CO intermediates to participate in the CHx-CO coupling process and simultaneously inhibited alkylation reactions. The present work points out a promising new strategy for constructing CuCo-based catalysts with favorable interfacial sites for highly efficient CO2 hydrogenation to produce ethanol.

Semi-quantitative design of synergetic surficial/interfacial sites for the semi-continuous oxidation of glycerol.

Qualitatively identifying the dominant catalytic site for each step of a semi-continuous reaction and semi-quantitatively correlating such different sites to the catalytic performance is of great significance toward the integration of multiple well-optimized sites on a heterogeneous catalyst. Herein, a series of structurally defined TiOx-based catalysts were synthesized to provide a feasible approach to investigate the aforementioned issues using the semi-continuous oxidation of glycerol as a model reaction. Detailed investigations have verified the simultaneous presence of two kinds of Pt active sites: 1) Negatively charged Pt bound to the oxygen vacancies of modified TiOx in the form of Ptδ--Ov-Ti3+ sites and 2) metallic Pt (Pt0 site) located away from the interface. Meanwhile, the proportion of surficial and interfacial sites varies over this series of catalysts. Combined in situ FTIR experiments revealed that the reaction network was well-tuned via a site cooperation mechanism: The surficial Pt0 sites dissociatively adsorb the OH group of glycerol with a monodentate bonding geometry and the Ptδ--Ov-Ti3+ sites dissociate the C=O bond of the aldehyde group in a bidentate form. Furthermore, CO-FTIR spectroscopy confirmed a correlation between the reaction rate/product selectivity and the fraction of surficial/interfacial sites. A rational proportion of surficial and interfacial sites is key to enabling a high yield of glyceric acid. The most active catalyst with 32% surface sites and 68% interfacial sites exhibited 90.0% glycerol conversion and 68.5% GLYA selectivity. These findings provide a deeper understanding of the structure-activity relationships using qualitative identification and semi-quantitative analysis.

Interfacial Sites in Ag Supported Layered Double Oxide for Dehydrogenation Coupling of Ethanol to n-Butanol.

Upgrading of ethanol to n-butanol through dehydrogenation coupling has received increasing attention due to the wide application of n-butanol. But the enhancement of ethanol dehydrogenation and followed coupling to produce high selectivity to n-butanol is still highly desired. Our previous work has reported an acid-base-Ag synergistic catalysis, with Ag particles supported on Mg and Al-containing layered double oxides (Ag/MgAl-LDO). Here, Ag-LDO interfaces have been manipulated for dehydrogenation coupling of ethanol to n-butanol by tailoring the size of Ag particles and the interactions between Ag and LDO. It has been revealed that increasing the population of surface Ag sites at Ag-LDO interfaces promotes not only the dehydrogenation of ethanol to acetaldehyde but also the subsequent aldol condensation of generated acetaldehyde. A selectivity of up to 76 % to n-butanol with an ethanol conversion of 44 % has been achieved on Ag/LDO with abundant interfacial Ag sites, much superior to the state-of-the-art catalysts.