Hydrogen Gas Sensor Based Upon Proton Acceptors Integrated in Copper-Tetra-2,3-Pyridinoporphyradine

We have previously developed a novel H
₂
gas sensor based upon a high proton affinity of diketodipyridylpyrrolopyrrole. Protonation is found to bring about a remarkable reduction of the electrical resistivity and this effect has been applied to H
₂
gas sensors. In the present investigation, an attempt was made to integrate proton acceptors (i.e., pyridyl rings) into copperphthalocyanine in order to improve the sensor characteristics. The present sensor exhibits a remarkable change in electrical resistivity by three orders of magnitude even under 0.01% H
₂
. Furthermore, the sensor is found to operate reversibly at room temperature and is scarcely influenced by ambient gases such as CH
₄
, CO, CO
₂
, NO, SO
₂
, CH
₃
OH, C
₂
H
₅
OH, and H
₂
O moisture