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Bimetallic Pd1Nix alloys supported on nitrogen-doped carbon (Pd1Nix/N–C, x = 0.37, 1.3 and 3.6) exhibit higher activities than Pd/N–C towards dehydrogenation of formic acid (HCO2H, FA). Density functional theory (DFT) calculations provided electronic and atomic structures, energetics and reaction pathways on Pd(111) and Pd1Nix(111) surfaces of different Pd/Ni compositions. A density of states (DOS) analysis disclosed the electronic interactions between Pd and Ni revealing novel active sites for FA dehydrogenation. Theoretical analysis of FA dehydrogenation on Pd1Nix(111) (x = 0.33, 1 and 3) shows that the Pd1Ni1(111) surface provides optimum H2-release efficiency via a favorable ‘HCOO pathway’, in which a hydrogen atom and one of the two oxygen atoms of FA interact directly with surface Ni atoms producing adsorbed CO2 and H2. The enhanced efficiency is also attributed to the blocking of an unfavorable ‘COOH pathway’ through which a C–O bond is broken and side products of CO and H2O are generated.

Hydrogen energy is a potential next-generation energy source for fossil fuel replacement. The development of high-efficiency materials and catalysts for storage and transportation of hydrogen energy must be achieved to realize hydrogen economy. Recently, catalyst systems such as Pd nanoclusters (Pd NCs) supported on nickel hydroxide (Ni(OH)2) have been reported to have advantages, including effective suppression of CO production and efficiency enhancement of HCOOH dehydrogenation. However, the reaction mechanism and multi-metallic interface system design of such systems have not been elucidated. Therefore, various Ni(OH)2 surfaces supported on a graphene system were designed through density functional theory calculations, and the support material was combined with Pd38NC (Pd38NC/Ni(OH)2-G). Subsequently, the adsorption behavior of HCOOH dehydrogenation intermediates was analyzed. We found a new adsorption configuration in which HCOOH* (where * and a single underline indicates the adsorbed species and adsorbed atom, respectively) was adsorbed in a more stable manner (adsorption energy, Eads= −1.22eV) on the system than HCOOH* (Eads=−1.10eV) owing to the presence of Ni(OH)2-G. This affected the next step in HCOOH dehydrogenation, i.e., formation of HCOO* species, and showed a positive effect on the HCOOH dehydrogenation. To fundamentally understand this phenomenon, electronic structure (d-band center and density of states) and stability (vacancy formation energy) analyses were performed.

The aim of this study is to evaluate maternal and neonatal outcomes following immediate delivery or expectant management of preterm premature rupture of membranes (PPROM) during the late preterm period at 34+ 0–36+ 6 weeks of pregnancy. We conducted a retrospective study on singleton pregnancies with PPROM during the late preterm period using medical records at twelve tertiary medical centres in Korea from January 2007 to December 2016. Data on demographic characteristics and outcome measures were collected. The primary outcomes were maternal sepsis for maternal outcome and neonatal sepsis and neonatal death for neonatal outcomes. Of the 1,072 women, 782 cases (72.9%) were assigned to the immediate delivery group, and 290 cases (27.1%) were categorized into the expectant management group. There was a significant difference in the rate of clinical neonatal sepsis (immediate delivery, 3.8% vs expectant management, 15.8%; p