Demonstrating Concepts in Catalysis, Renewable Energy, and Chemical Safety with the Catalytic Oxidation of Hydrogen

Abstract

A versatile and portable apparatus was developed to demonstrate exciting visual displays of catalytic phenomena that introduce basic concepts in catalysis, renewable energy, and chemical safety, in order to pique scientific curiosity in a variety of audiences including middle and high school students, undergraduate and graduate students, and the general public. The demonstration uses the platinum-catalyzed oxidation of hydrogen by oxygen as a model reaction to illustrate concepts in thermodynamics, reaction kinetics, and electrochemistry. The apparatus was designed to contain inherent safety features and the versatility to adopt several configurations to perform a wide range of experiments in classroom settings, informal science education activities, and public outreach events. Soap bubbles are used to confine small, controlled volumes (<35 cm3) of hydrogen/oxygen gas mixtures and probe the reactivity of bulk and nanoparticle forms of platinum to illustrate how high metal surface areas increase catalytic reaction rates. In parallel, a hydrogen/oxygen proton-exchange fuel cell is used to demonstrate how chemical energy released from the exergonic hydrogen oxidation reaction can be converted into electricity by using a platinum-containing electrocatalyst. With adjustments of the operating configuration and the experimental conditions of the apparatus, the demonstrations can be tailored toward target demographics of varying scientific proficiency to emphasize specific learning objectives for topics in reaction chemistry and engineering. Potential hazards and important safety precautions are addressed.

Understanding the Problem of Hydrogen Storage Using a Demonstration: Coupling a Hydrogen Generator Based on the Hydrolysis of Sodium Borohydride to a Fuel-Cell Kit

“…However, it is important to note that SB releases hydrogen but is not hydrogen gas itself and is, therefore, safer to use. The black solid that is generated at the beginning of the hydrogen release reaction is a Co–B catalyst, which is formed in situ by the reaction of the cobalt salt with SB. ,, The role of the catalyst is to accelerate the spontaneous reaction. , Moreover, the use of heterogeneous catalysts permits recovery and reuse, constituting an advantage with respect to homogeneous catalysts. , …”

“…15,19 Moreover, the use of heterogeneous catalysts permits recovery and reuse, constituting an advantage with respect to homogeneous catalysts. 15,19 At the end of the demonstration, we may ask the audience how we can prove that the released gas is hydrogen. By coupling the borohydride reactor to the FC, the production of electricity definitely proves that the hydrolysis of SB does indeed release hydrogen, as shown in reactions 1 and 3.…”

“…9,23,25 The role of the catalyst is to accelerate the spontaneous reaction. 15,19 Moreover, the use of heterogeneous catalysts permits recovery and reuse, constituting an advantage with respect to homogeneous catalysts. 15,19 At the end of the demonstration, we may ask the audience how we can prove that the released gas is hydrogen.…”

“…The hydrogen generated with this reaction is free from carbon monoxide and can be used to feed a fuel cell (FC), producing electricity with water as the only byproduct. − The reaction byproduct, sodium metaborate (NaBO 2 ), is nontoxic and requires extraction from the reaction medium for recycling back to NaBH 4 . , The hydrolysis of SB is not reversible when applied on-board, but holds promise for portable and off-grid applications.…”

In Situ Infrared Spectroscopy of NOx Reduction Catalysts: A Laboratory Exercise for In-Person and Virtual Learning

“…Given its vast industrial significance, catalysis is also ingrained in the chemistry curriculum, − but its concept is usually not introduced in conjunction with IR spectroscopy except in specialized electives or graduate-level courses. Notwithstanding, IR spectroscopy remains to be one of the most widely used characterization techniques in catalysis research.…”