Hydrogen Gas Sensors Based upon Organic Pigments

Abstract

Hydrogen gas sensor utilizing a high proton affinity of 1, 4-diketo-3, 6-bis-(4'-pyridyl)-pyrrolo-[3, 4-c]-pyrrole known as a red pigment has been reviewed. The present sensor is derived from an originally proton sensor (i.e. acid sensor) based upon the proton acceptor of the pyridyl ring in view of the advent of the fuel cell in the near future. Special attention has been paid to the correlation between H₂ sensitivity and crystal structure. The sensor is characterized by a high H₂ sensitivity, reversible operation at room temperature and scarcely influenced by ambient gases, such as CO, CO₂, NO, CH₄, SO₂, CH₃OH, C₂H₅ OH as well as water moisture. Similar H₂ sensors based upon dipyridylperylene-imides or tetrapyridylcopperphthalocyanine have also been presented.