Methods of producing a gas at a controlled rate

A method of producing a gas at a controlled rate, the method comprising:

• directing air to flow through a layered bed for a first amount of time to produce the gas from a precursor, after which the flow of air through the layered bed ceases for a second amount of time, and, after the second amount of time, air is directed to flow through the layered bed for a third amount of time;
• wherein the layered bed comprises alternating layers of a layer of dry particles comprising the precursor and a layer of dry particles comprising a proton-generating species, wherein the total number of layers in the layered bed is 3 or more;
• wherein the gas is produced at a rate that is controlled by controlling the presence or absence of air flowing though the layered bed, the first amount of time for which the air flows through the layered bed, the second amount of time for which the flow of air through the layered bed ceases, the third amount of time for which the air flows through the layered bed, the total number of layers in the layered bed, the average thickness of each of the layers of dry particles comprising the precursor in the layered bed, and the average thickness of each of the layers of dry particles comprising the proton-generating species in the layered bed;
• wherein the dry precursor particles comprise a carbon dioxide precursor and the gas comprises carbon dioxide;
• wherein the average thickness of each of the layers of dry particles comprising the precursor in the layered bed is from 2.5 centimeters (cm) to 25 cm;
• and
• wherein the average thickness of each of the layers of dry particles comprising the proton-generating species in the layered bed is from 2.5 to 25 cm.