Development of high surface area bulk W2N catalysts for hydrogen production from ammonia decomposition

Abstract

High surface area tungsten nitride catalysts synthesized from ammonium meta-tungstate and employed as catalysts for ecofriendly H2 production from NH3. A series of tungsten nitride catalysts synthesized by using CiA (citric acid) as chelating agent with different molar ratio of W and CiA. The synthesized materials characterized using BET-surface area, X-ray diffraction, X-ray photoelectron spectroscopy and SEM techniques. The BET value of as-synthesized tungsten nitride was raised from 25 to 80 m2 g−1. The influence of amount of CiA in preparation on the catalyst's surface area was investigated. The catalyst performance measured within the desired range of temperature 300–600 °C. A pure phase of tungsten nitride was formed by this preparation method. The catalyst with the ratio of CiA/W = 3 exhibited the best catalytic performance. The increased activity of WN-31 catalyst was mainly due to increased surface area, decreased particle size and high surface concentration. The WN-31 catalyst showed stable performance during time on study for 25 h. These bulk tungsten-based materials are easy to synthesize and highly stable material in the reaction atmosphere.