A Family of High-Efficiency Hydrogen-Generation Catalysts Based on Ammonium Species

Abstract

Development of highly active, low cost, ecologically friendly, and durable homogenous catalysts for hydrogen generation from hydrolysis of borohydride is one of the most desirable pathways for future hydrogen utilization. The unexpected catalytic activities of inorganic ammonium species and the corresponding mechanisms underpinning them are studied. The catalytic activities of the ammonium species are higher than or comparable to those of mostly investigated noble-metal/transition-metal catalysts (such as Pd, Pt, Ni, and Co) but are considerably cheaper, more environmentally friendly, and more readily available. Quantum chemical calculations indicate that the unique ammonium-induced reaction pathway involved with a barrierless elementary reaction at the reaction entrance and the formation of the highly active intermediate BH 3 are responsible for the unexpected catalytic activities and the significantly accelerated hydrogen generation. The catalytic activities of inorganic ammonium ions for hydrogen generation by the hydrolysis of borohydrides and the corresponding mechanisms were investigated. The catalytic activities were higher than or comparable to those of typical noble-metal/transition-metal catalysts but the ammonium ions are considerably cheaper, more environmentally friendly, and more readily available.