Size- and structure-controlled mono- and bimetallic Ir–Pd nanoparticles in selective ring opening of indan

The Structure and Crystallizing Process of NiAu Alloy: A Molecular Dynamics Simulation Method

This paper studies the influence of factors such as heating rate, atomic number, temperature, and annealing time on the structure and the crystallization process of NiAu alloy. Increasing the heating rate leads to the moving process from the crystalline state to the amorphous state; increasing the temperature (T) also leads to a changing process into the liquid state; when the atomic number (N), and t increase, it leads to an increased crystalline process. As a result, the dependence between size (l) and atomic number (N), the total energy of the system (Etot) with N as l~N−1/3, and −Etot always creates a linear function of N, glass temperature (Tg) of the NiAu alloy, which is Tg = 600 K. During the study, the number of the structural units was determined by the Common Neighborhood Analysis (CNA) method, radial distribution function (RDF), size (l), and Etot. The result shows that the influencing factors to the structure of NiAu alloy are considerable.

Double enhancement of hydrogen storage capacity of Pd nanoparticles by 20 at% replacement with Ir; systematic control of hydrogen storage in Pd-M nanoparticles (M = Ir, Pt, Au)

We report on binary solid-solution nanoparticles (NPs) composed of Pd and Ir, which are not miscible at the equilibrium state of the bulk, for the first time, by means of a process of hydrogen absorption/desorption from core (Pd)/shell (Ir) NPs. Only 20 at% replacement with Ir atoms doubled the hydrogen-storage capability compared to Pd NPs, which are a representative hydrogen-storage material. Furthermore, the systematic control of hydrogen concentrations and the corresponding pressure in Pd and Pd-M NPs (M = Ir, Pt, Au) have been achieved based on the band filling control of Pd NPs.

Nanoporous IrO2 catalyst with enhanced activity and durability for water oxidation owing to its micro/mesoporous structure

Herein, we report a nanoporous IrO₂ catalyst with a surface area of 363.3 m² g^-1, the highest ever reported. The IrO₂ catalysts were prepared by a facile ammonia-induced pore-forming method, and efficiently scaled up to several kilograms. Bimodal micro/mesopores were created at once without using a template. For the IrO₂ (1 : 100)-450 °C (H₂IrCl₆ : NH₃·H₂O of 1 : 100) catalyst, the overpotential to attain a current density of 10 mA cm^-2 for water oxidation was only 282 mV, and furthermore, its excellent durability was confirmed by accelerated durability tests. Moreover, the overall voltage to achieve a current density of 1000 mA cm^-2 in a water electrolysis cell was only 1.649 V, making IrO₂ (1 : 100)-450 °C a highly attractive catalyst for water electrolysis applications.

Catalytic performance of Pd-promoted Cu hydrotalcite-derived catalysts in partial hydrogenation of acetylene: effect of Pd–Cu alloy formation

A highly dispersed PdCu nanoalloy catalyst derived from a CuMgAl-hydrotalcite precursor exhibited superior catalytic performance in partial hydrogenation of acetylene.

Combinatorial high-throughput optical screening of high performance Pd alloy cathode for hybrid Li-air battery

Combinatorial high-throughput optical screening method was developed to find the optimum composition of highly active Pd-based catalysts at the cathode of the hybrid Li-air battery. Pd alone, which is one-third the cost of Pt, has difficulty in replacing Pt; therefore, the integration of other metals was investigated to improve its performance toward oxygen reduction reaction (ORR). Among the binary Pd-based catalysts, the composition of Pd-Ir derived catalysts had higher performance toward ORR compared to other Pd-based binary combinations. The composition at 88:12 at. % (Pd: Ir) showed the highest activity toward ORR at the cathode of the hybrid Li-air battery. The prepared Pd(88)Ir(12)/C catalyst showed a current density of -2.58 mA cm(-2) at 0.8 V (vs RHE), which was around 30% higher compared to that of Pd/C (-1.97 mA cm(-2)). When the prepared Pd(88)Ir(12)/C catalyst was applied to the hybrid Li-air battery, the polarization of the cell was reduced and the energy efficiency of the cell was about 30% higher than that of the cell with Pd/C.

A study to initiate development of sustainable Ni/γ-Al2O3 catalyst for hydrogen production from steam reforming of biomass-derived glycerol

Glycerol steam reforming, a potential technology for hydrogen production in fuel-cell applications, is of great interest to researchers in recent years.