Search

Developing effective catalysts for hydrogen production from ammonia-borane (AB) hydrolysis is highly important for the potential usage of hydrogen-based energy. Here, phosphorus-doped carbon (PPC) derived from hypercrosslinked polymer networks of triphenylphosphine and benzene was employed as support to synthesize Ru/PPC through the in situ stabilization of ultrafine and uniform Ru nanoclusters (NCs). It was found that the Ru NCs with a mean diameter of 1.13 nm dispersed well on the PPC surface. The Ru/PPC exhibited a high turnover frequency of 413 mol H2 (molRu·min)−1 under mild conditions. The high catalytic performance of Ru/PPC could be ascribed to the small size of metal, which can offer more catalytically active components for the reaction. This work reveals that the PPC has promising potential catalyst support in stabilizing metal NCs for AB hydrolysis to generate hydrogen.

Developing effective catalysts for hydrogen evolution from hydrolysis of ammonia borane (AB) is of great significance considering the useful applications of hydrogen. Herein, graphitic carbon nitride (g-C3N4) prepared through the simply pyrolysis of urea was employed as a support for Rh nanoparticles (NPs) stabilization. The in-situ generated Rh NPs supported on g-C3N4 with an average size of 3.1 nm were investigated as catalysts for hydrogen generation from the hydrolysis of AB under mild conditions. The Rh/g-C3N4 catalyst exhibits a high turnover frequency of 969 mol H2· (min·molRh)−1 and a low activation energy of 24.2 kJ/mol. The results of the kinetic studies show that the catalytic hydrolysis of AB over the Rh/g-C3N4 catalyst is a zero-order reaction with the AB concentration and a first-order reaction with the Rh concentration. This work demonstrates that g-C3N4 is a useful support to design and synthesis of effective Rh-based catalyst for hydrogen-based applications.

Hydrogen generation from the hydrolysis of ammonia borane (AB) over heterogeneous catalysts is essential for practical applications. Herein, efficient hydrogen evolution from AB hydrolysis over the carbon-supported Rh nanoparticles synthesized with sodium citrate (Rh/C-SC) was achieved at 25 °C. The turnover frequency value of Rh/C-SC was 336 mol H2 (molRh min)−1, whereas that of Rh/C catalyst only yielded a value of 134 mol H2 (molRh min)−1. The improvement of the catalytic performance of Rh/C-SC catalyst could be attributed to the small Rh particles with highly active surface areas, which were prepared by using sodium citrate as the stabilizing agent. This result indicates that sodium citrate can be applied as a useful stabilizing agent for synthesizing active metal nanoparticles, thus highly promoting the practical application of AB system for fuel cells.

Effective catalysts for hydrogen generation from ammonia borane (AB) hydrolysis should be developed for the versatile applications of hydrogen. In this study, ruthenium nanoparticles (NPs) supported on alumina nanofibers (Ru/Al2O3-NFs) were synthesized by reducing the Ru(Ш) ions impregnated on Al2O3-NFs during AB hydrolysis. Results showed that the Ru NPs with an average size of 2.9 nm were uniformly dispersed on the Al2O3-NFs support. The as-synthesized Ru/Al2O3-NFs exhibited a high turnover frequency of 327 mol H2 (mol Ru min)−1 and an activation energy of 36.1 kJ mol−1 for AB hydrolysis at 25 °C. Kinetic studies showed that the AB hydrolysis catalyzed by Ru/Al2O3-NFs was a first-order reaction with regard to the Ru concentration and a zero-order reaction with respect to the AB concentration. The present work reveals that Ru/Al2O3-NFs show promise as a catalyst in developing a highly efficient hydrogen storage system for fuel cell applications.

Preparation of catalysts with high catalytic activity toward hydrogen generation from ammonia borane (AB) hydrolysis is of significant importance because of the important and versatile applications of hydrogen. Herein we report the synthesis of Ru nanoparticles supported on nanodiamond by a one-step approach through the reduction of RuCl 3 using AB as reducing agent. The nanocomposites surfaces with large quantity of oxygen-containing functional groups such as hydroxyl and carboxylic groups resulted in a homogeneous suspension in aqueous phase. The catalytic activity of Ru/nanodiamond was studied for hydrogen generation from AB hydrolysis at 25 °C. Results indicated that nanodiamond supported Ru nanoparticles with a mean particle size of 3.7 nm exhibited high catalytic activity for AB hydrolysis, with a turnover frequency number of 229 mol H 2 · (mol Ru·min) −1 . The high catalytic activity of Ru/nanodiamond demonstrates that nanodiamond is a good media for nanoparticles immobilization.