Bionic design of gas sensors for selective switching and humidity suppression

Currently, research on selectivity modulation and humidity suppression for semiconductor metal oxide gas sensors remains relatively limited. Inspired by the lipid bilayer model of biological cell membranes and grounded in Lewis acid-base theory, we propose a biomimetic acid-base bilayer model analogous to the electric double layer theory. By in situ growing two-dimensional α-bismuth molybdate (α-Bi₂Mo₃O₁₂) on porous ZnO nanosheets, the selectivity of the sensor is switched from the original Lewis basic ZnO (which responds to acidic acetic anhydride) to the composite material (which responds to alkaline triethylamine), thereby achieving selective Switching. The sensor based on this acid-base bilayer model exhibits a response value of 48.6 toward 100 ppm triethylamine, with a detection limit as low as 50 ppb. Notably, water molecules generate hydroxyl groups on Lewis acidic sites, which in turn facilitate electron transport as bridging sites, thereby achieving suppression of humidity interference. This work provides a novel strategy and theoretical support for the design of highly selective sensors, contributing to the advancement of high-performance semiconductor gas sensors.