Metal (Oxy)nitride Interfaces for Environmental Gas Monitoring

Abstract

Environmental gas monitoring is moving beyond dry calibration chambers toward measurements in humid exhaust, wastewater headspace, refrigerated packages, and exhaled breath. Existing sensor platforms often struggle to combine room-temperature operation, low power demand, sulfur resistance, and long-term response stability within a single device. This Perspective examines metal nitride and oxynitride interfaces, which provide access to mixed-anion coordination, tunable vacancy states, conductive nitride frameworks, and strong metal–support interactions. Drawing on recent NO₂ and H₂S studies from our group, we trace how oxide nitridation, vacancy-engineered TiN and WN, redox-paired TiN/SnO₂ electrodes, and Pt/nitride supports enable room-temperature sensing while retaining functionality under high-humidity, sulfur-containing, or low-temperature conditions. These interfaces have been demonstrated in exhaust-related, wastewater, cold-chain, and breath-monitoring scenarios, highlighting the need to match interfacial chemistry with the target matrix. We argue that metal (oxy)nitride interfaces may become difficult to replace in distributed sensing scenarios that simultaneously require room-temperature redox activity, efficient charge transport, catalyst stabilization, and tolerance to humidity, sulfur, or low temperature.