Effect of Pt/TiO2 interface on room temperature hydrogen sensing performance of memristor type Pt/TiO2/Pt structure

Abstract In this paper, a sensor with memristor electrode geometry (Pt/TiO 2 /Pt) was fabricated by a simple and cost-effective method yielding 10 6 orders of resistance change with short reaction times (T res  ∼ 19 and T rec  ∼ 118 s) when exposed to 1 vol.% H 2 . Under wet conditions an increase in sensor response toward 1 vol.% H 2 independent of operating temperature RT–100 °C (T res  ∼ 5 s) and a reasonable H 2 -selectivity was observed in the presence of CO and NO 2 . Such sensor characteristics with lower power consumption offer great advantages and are highly suitable for fuel cell and hydrogen safety applications. Despite the knowledge that hydrogen atoms accumulate at Pt/TiO 2 interface reducing Schottky barrier height (i.e. decreasing the resistance of the Pt/TiO 2 interface by several orders of magnitude) the details of the involved sensing mechanisms, especially under humidity, is still incomplete. The results confirm the existence of both electronic and ionic conductivity within TiO 2 sensing layer and their significant alteration under hydrogen exposure. Thus a sensing model is proposed that fit exceptionally well with the memristor-type resistance variation principle. The understanding gained by the proposed model will allow the fabrication of innovative sensors for stable, selective and robust H 2 detection.