Ultrafast response and recovery trimethylamine sensor based on α-Fe2O3 snowflake-like hierarchical architectures

Abstract

Snowflake-like α-Fe2O3 hierarchical architectures have been developed to detect trimethylamine (TMA) gas. The α-Fe2O3 has been synthesized by using a facile solvothermal method and a subsequent annealing process. As-fabricated snowflake-like α-Fe2O3 based sensor exhibits ultrafast response and recovery time (0.9 s/1.5 s), excellent selectivity, high response, and superior repeatability toward TMA gas. XPS, PL and UV indicates that abundant oxygen vacancies exist in the α-Fe2O3 surfaces. Oxygen vacancies provide essential active sites for gas adsorption which enormously improve the ability of electron transfer. The remarkable TMA sensing performance can be attributed to the cooperation of oxygen vacancies providing more active sites, rapid electron exchange between Fe3+ and Fe2+ cations inducing conductivity greatly change, and unique snowflake-like hierarchical structure possessing large contacting area and monocrystalline feature. Such novel snowflake-like α-Fe2O3 hierarchical architectures will be a promising candidate for TMA, fish and sea-food freshness detection.