This study describes a new C-H bond activation pathway during CH-CO reactions on oxophilic Ni-Co and Co clusters, unlike those established previously on Ni clusters. The initial C-H bond activation remains as the sole kinetically relevant step on Ni-Co, Ni, and Co clusters, but their specific reaction paths vary. On Ni clusters, C-H bond activation occurs via an oxidative addition step that involves a three-center (HC···*···H) transition state, during which a Ni-atom inserts into the C-H bond and donates its electron density into the C-H bond's antibonding orbital. Ni-Co clusters are more oxophilic than Ni; thus, their surfaces are covered with oxygen adatoms. An oxygen adatom and a vicinal Co-atom form a metal-oxygen site-pair that cleaves the C-H bond via a σ bond metathesis reaction, during which the Co inserts into the C-H bond while the oxygen abstracts the leaving H-atom in a concerted, four-center (HC···*···H···O*) transition state. Similarly, Co clusters also catalyze the σ bond metathesis step, but much less effectively because of their higher oxophilicities, much stronger binding to oxygen, and less effective hydrogen abstraction than Ni-Co clusters. On Ni-Co and Co clusters, the pseudo-first-order rate coefficients are single-valued functions of the CO-to-CO ratio (or HO-to-H ratio), because this ratio prescribes the oxygen chemical potentials and the relative abundances of metal-oxygen site-pairs through the water-gas shift equilibrium. The direct involvement of reactive oxygen in the kinetically relevant step leads to more effective CH turnovers and complete elimination of coke deposition on Ni-Co bimetallic clusters.

The substitution of base-metal oxides for noble metals is a great challenge for catalysts, sensors, and other functional materials. In this work, the dynamic structure at the interface of binary metal oxides, as a popular natural phenomenon in material science and catalysis, was studied in detail in the case of a binary copper−ceria species (CuO x -CeO 2 ). The catalytic activity of CuO x -CeO 2 could be largely improved by doping indium oxide (In 2 O 3 ). The reaction rate of 1.26 × 10 −5 mol CO g cat.−1 s −1 for a 1.25In5Cu/CeO 2 catalyst toward CO oxidation is 12 times higher than that from commercial Pd catalysts. In addition, the indiumdoped catalyst shows strong resistance to CO 2 and H 2 O poisoning. We determined the dynamic interfacial structure of CuO x /CeO 2 catalysts induced by In 2 O 3 during CO oxidation using in situ techniques, intrinsic kinetics, and density functional theory calculations (DFT). Indeed, the surface of CuO x particles could be reconstructed through the interaction with In 2 O 3 . Such an interaction not only helps to generate more active sites at interfaces between CuO x and CeO 2 but also lowers the CO adsorption strength and reduces the accumulation of surface carbonates. Meanwhile, In 2 O 3 could also modify the electronic structure to improve the reducibility of CuO x , thus shifting the redox equilibrium of Cu 2+ + Ce 3+ ↔ Cu + + Ce 4+ to create Cu + or Cu 0 species at the interfacial sites. This study not only reveals the dynamic interfacial structure of metal oxide catalysts but also demonstrates a feasible way to fine-tune the interfacial structure of binary metal oxides.

The transmission of normal sensory and/or acute noxious information requires intact expression of pain-associated genes within the pain pathways of nervous system. Expressional changes of these genes after peripheral nerve injury are also critical for neuropathic pain induction and maintenance. Methyl-CpG-binding domain protein 1 (MBD1), an epigenetic repressor, regulates gene transcriptional activity. We report here that MBD1 in the primary sensory neurons of DRG is critical for the genesis of acute pain and neuropathic pain as DRG MBD1-deficient mice exhibit the reduced responses to acute mechanical, heat, cold, and capsaicin stimuli and the blunted nerve injury-induced pain hypersensitivities. Furthermore, DRG overexpression of MBD1 leads to spontaneous pain and evoked pain hypersensitivities in the WT mice and restores acute pain sensitivities in the MBD1-deficient mice. Mechanistically, MDB1 represses Oprm1 and Kcna2 gene expression by recruiting DNA methyltransferase DNMT3a into these two gene promoters in the DRG neurons. DRG MBD1 is likely a key player under the conditions of acute pain and neuropathic pain.

Highly selective hydrogen peroxide (H O ) synthesis directly from H and O is a strongly desired reaction for green processes. Herein a highly efficient palladium-tellurium (Pd-Te/TiO ) catalyst with a selectivity of nearly 100 % toward H O under mild conditions (283 K, 0.1 MPa, and a semi-batch continuous flow reactor) is reported. The size of Pd particles was remarkably reduced from 2.1 nm to 1.4 nm with the addition of Te. The Te-modified Pd surface could significantly weaken the dissociative activation of O , leading to the non-dissociative hydrogenation of O . Density functional theory calculations illuminated the critical role of Te in the selective hydrogenation of O , in that the active sites composed of Pd and Te could significantly restrain side reactions. This work has made significant progress on the development of high-selectivity catalysts for the direct synthesis of H O at ambient pressure.