Dual-working-electrode mixed potential type ammonia gas sensor and preparation method thereof

Abstract

The invention relates to a dual-working-electrode mixed potential type ammonia gas sensor and a preparation method thereof. The sensor comprises a solid electrolyte substrate, and a positive working electrode and a negative working electrode which are arranged on the solid electrolyte substrate, and the positive working electrode and the negative working electrode are symmetrically arranged at two ends of the solid electrolyte substrate. According to the sensor disclosed by the invention, a reference electrode is replaced, and the positive electrode and the negative electrode are combined, so that the overall output signal of the sensor can be increased, a recognizable signal can be generated when the ammonia concentration is as low as ppb level, and the lower detection limit of the mixed potential type ammonia sensor is reduced; and the detection concentration requirement that the escape concentration of ammonia gas in national VI emission is less than 10ppm can be effectively met.

Description

technical field [0001] The invention relates to a technology in the field of gas sensors, in particular to a double working electrode mixed potential ammonia sensor and a preparation method thereof. Background technique [0002] Selective catalytic reduction (SCR) technology is an essential technology for controlling nitrogen oxide (NOx) emissions from diesel vehicles, ships and power stations. In the SCR aftertreatment system, ammonia gas (NH 3 ), ammonia gas participates in the SCR reaction to remove nitrogen oxides. China's sixth phase of pollutant emission limits for heavy-duty diesel vehicles (GB17691-2018) stipulates that the emission limits of nitrogen oxides and ammonia are 460mg / kWh and 10ppm, respectively. Therefore, the SCR system needs to be equipped with an ammonia sensor to form a closed-loop control of the injection of the reducing agent (urea solution or ammonia gas), improve the SCR reaction efficiency and reduce the leakage of ammonia gas. At the same ti...

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Problems solved by technology

However, the existing mixed potential ammonia sensor composed of three parts: sensitive electrode, solid electrolyte, and reference electrode still has three problems: high detection limit, low sensitivity, and weak anti-nitrogen oxide interference ability.

[0004] After searching the prior art, it was found that the Chinese Patent Document No. CN201410675433.7, published on 2015.02.18, discloses a Ni 3 V 2 o 8 YSZ-based mixed potential NH for sensitive electrodes 3 Sensor and preparation method, but compared with the present invention in this prior art, the overall sensitivity of the sensor is relatively low, the lower limit of detection is high, and the signal response ability is low

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