The high-precision detection of gaseous pollutant concentrations, such as ammonia (NH3), in industrial environments has become a key assessment indicator for enterprises to reduce emissions and consumption. Improving sensor detection accuracy and data transmission efficiency is a much-needed technology for the digital transformation of factories in the Internet of things (IoT) era. In this study, a high-precision cerium oxide/vanadium carbide (CeO2/V2C) ammonia sensor capable of operating at room temperature was prepared by an in situ polymerization method. V2C with a large specific surface area can act as a broad platform for attaching CeO2, as seen from the characterization, which contributes to the high performance synergy effect. This allows the NH3 sensor to still exhibit an excellent response value (36.8%@50 ppb NH3), extraordinarily low detection limit (25 ppb NH3), stability (>60 days) and fast response/recovery time (12 s/19 s@50 ppb NH3) for very low concentrations of ammonia gas. Based on the sensor parameters, the circuit modules of Bluetooth, Near Field Communication (NFC) and IoT data are designed, which realizes the factory emission detection, personnel safety management and gas leak inspection. All the monitoring data are visualized on the computer side and cell phone side. A freestanding-mode triboelectric nanogenerator that can be driven by wind and water is explored. As a promising energy harvesting technology, it provides a new energy pathway for the implementation of the monitoring of ammonia.