Anti-sulfur poisoning and highly sensitive portable detection instrument for monitoring of hydrogen sulfide on-site

The susceptibility of sensors to sulfur poisoning is the biggest challenge when monitoring high concentrations of hydrogen sulfide (H 2 S). In order to solve this problem, a portable detection instrument based on electrochemical sensor was developed. The “chainmail” catalyst of graphene-encapsulated cobalt-nickel nanoparticles (CoNi@NGs) was synthesized and doped with conductive carbon black (CCB) as sensing material. The graphene shell could protect core metal from sulfur poisoning. The anti-sulfur poisoning performance of the developed instrument reached the best level in literature. After 60 days of intermittent detection of 100 ppm H 2 S or on-site monitoring in wastewater treatment tank, the signals only decreased by 1.3 % and 1.6 %, respectively. By doping CCB, a porous structure was constructed on the working electrode membrane (WEM), which reduced the response and recovery time by 87.9 % and 77.0 %, to 14 s and 24.5 s, respectively. In addition, the instrument had a wide detection range (20 ppb-700 ppm), high sensitivity (0.580 μA/ppm) and limit of detection (LOD) of 0.52 ppb (3σ). Finally, the instrument was applied to monitor of H 2 S in wastewater treatment tank and sewage sewer of an institute, which showed that the instrument had broad application prospects for on-site monitoring of H 2 S in real environments.