3D sulfonated graphene hydrogel for enhanced chemical sensing

One-step, hydrothermal synthesized 3D sulfonated reduced graphene oxide hydrogel (S-RGOH) is employed to fabricate a chemical sensor with high sensitivity, good selectivity, fast response and reversibility toward several gases. Compared with unmodified RGOH counterparts, the 3D NaHSO 3 functionalized S-RGOH sensor exhibits 61.3 and 58.9 times higher responses to NO 2 and NH 3 respectively. A low limit of detection (LOD) of 4.1 ppb and 1.48 ppm for NO 2 and NH 3 , respectively, has been achieved. The sensor exhibits fast and complete recovery at room temperature. Importantly, for the first time, the characteristics of a linear fitted response-temperature relationship are exploited to discriminate many different gases. An integrated microheater is deployed to modulate substrate temperature rapidly with low power consumption.