Zeolite confined rhodium(0) nanoclusters as highly active, reusable, and long-lived catalyst in the methanolysis of ammonia-borane


Caliskan S., Zahmakiran M., ÖZKAR S.

APPLIED CATALYSIS B-ENVIRONMENTAL, vol.93, pp.387-394, 2010 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 93
  • Publication Date: 2010
  • Doi Number: 10.1016/j.apcatb.2009.10.013
  • Title of Journal : APPLIED CATALYSIS B-ENVIRONMENTAL
  • Page Numbers: pp.387-394
  • Keywords: Rhodium, Nanocluster, Zeolite, Methanolysis, Catalysis, Ammonia-borane, HYDROGEN GENERATION SYSTEM, SODIUM-BOROHYDRIDE, FAUJASITE ZEOLITES, ROOM-TEMPERATURE, RUTHENIUM(0) NANOCLUSTERS, THERMAL-DECOMPOSITION, HYDROLYSIS, STORAGE, NANOPARTICLES, COBALT

Abstract

Addressed herein is the preparation, characterization and the catalytic use of zeolite confined rhodium(0) nanoclusters in the methanolysis of ammonia-borane. Rhodium(0) nanoclusters; could be generated in zeolite-Y by a two-step procedure: (i) incorporation of rhodium(Ill) cations into the zeolite-Y by ion-exchange and (ii) reduction of rhodium(Ill) ions within the zeolite cages by sodium borohydride in aqueous solution, followed by filtration and dehydration by heating to 550 degrees C under 10(-4) Torr. Zeolite confined rhodium(0) nanoclusters are stable enough to be isolated as solid materials and characterized by ICP-OES, XRD. SEM, EDX, HR-TEM, XPS and N-2 adsorption-desorption technique. The zeolite confined rhodium(0) nanoclusters are isolable, bottleable, redispersible and reusable as an active catalyst in the methanolysis of ammonia-borane even at low temperatures. They provide exceptional catalytic activity with an average value of TOF = 380 h(-1) and unprecedented lifetime with 74,300 turnovers in the methanolysis of ammonia-borane at 25 +/- 0.1 degrees C. The work reported here also includes the full experimental details of the collection of a wealth of previously unavailable kinetic data to determine the rate law, and activation parameters (E-a, Delta H-not equal and Delta S-not equal) for the catalytic methanolysis of ammonia-borane. (C) 2009 Elsevier B.V. All rights reserved.