Enhanced Gas Sensitivity and Sensing Mechanism of Network Structures Assembled from α-Fe₂O₃ Nanosheets with Exposed {104} Facets

Abstract

Network structures assembled from α-FeO nanosheets with exposed {104} facets were successfully prepared by heating Fe(NO) solution containing polyvinylpyrrolidone (PVP) in air. The α-FeO nanosheet-based network structures demonstrate significantly higher response to ethanol and triethylamine than α-FeO commercial powders. The excellent sensing performances can be ascribed to the exposed (104) facet terminated with Fe atoms. A concept of the unsaturated Fe atoms serving as the sensing reaction active sites is thus proposed, and the sensing reaction mechanism is described at the atomic and molecular level for the first time in detail. The concept of the surface metal atoms with dangling bonds serving as active sites can deepen understanding of the sensing and other catalytic reaction mechanisms and provides new insight into the design and fabrication of highly efficient sensing materials, catalysts, and photoelectronic devices.

α‐Fe2O3 Polyhedral Nanoparticles Enclosed by Different Crystal Facets: Tunable Synthesis, Formation Mechanism Analysis, and Facets‐dependent n‐Butanol Sensing Properties

“…As an important n ‐type semiconductor with bandgap of 2.1 eV, hematite (α‐Fe 2 O 3 ) nanomaterials have attracted considerable attention due to its wide potential applications in many fields, such as magnetic devices, catalytic/photocatalytic fields, pigments, gas sensing, photo anode, and rechargeable lithium‐ion batteries . In recent years, α‐Fe 2 O 3 has been developed as one of the promising gas‐sensing materials due to their nontoxicity, low cost, high chemical stability and high sensitivity , . Increasing attention has been paid to rationally engineer the shape and exposed crystallographic facets of α‐Fe 2 O 3 nanocrystals to shed light on the relationship between the performance and structure.…”

Effects of size on the photocatalytic properties of high-index faceted pseudocubic and rhombohedral α-Fe2O3 nanocrystals

“…Plenty of work has conrmed that the {012} and {104} planes of a-Fe 2 O 3 are high-index planes. [31][32][33][34] Ma et al found that the exposed {104} planes of a-Fe 2 O 3 exhibits excellent gas sensing properties. 33 Zhao et al investigated that a-Fe 2 O 3 nanocubes exposed {012} active facets combination with graphene lead to boosted lithium storage capability.…”

“…[31][32][33][34] Ma et al found that the exposed {104} planes of a-Fe 2 O 3 exhibits excellent gas sensing properties. 33 Zhao et al investigated that a-Fe 2 O 3 nanocubes exposed {012} active facets combination with graphene lead to boosted lithium storage capability. 34 Recently, Xiang and coworkers reported that a-Fe 2 O 3 nanocubes with {012} facets have much higher photocatalytic water oxidation activity than a-Fe 2 O 3 nanoakes with {001} facets.…”

Artificial Synthesis and Improved Photo Catalysis Performance of Bionic Hierarchical Fibers Alpha-Fe2O3

“…5,6 Hematite (α-Fe 2 O 3 ), an important part of the iron oxide materials, is the most stable metal oxide with favorable optical band gap (about 2.06 eV). 7 The α-Fe 2 O 3 has been widely applied in photoelectrocatalytic water splitting, 8 environmental remediation, 9 sensor, 10 antimicrobial agents, 11 etc., due to its abundance, good stability, nontoxicity, and low cost. [7][8][9][10][11][12] The micro-or nano-biotemplate preparation of iron oxide was rarely reported.…”

“…7 The α-Fe 2 O 3 has been widely applied in photoelectrocatalytic water splitting, 8 environmental remediation, 9 sensor, 10 antimicrobial agents, 11 etc., due to its abundance, good stability, nontoxicity, and low cost. [7][8][9][10][11][12] The micro-or nano-biotemplate preparation of iron oxide was rarely reported. In this paper, the cotton was used as biological template with impregnation adsorbed with Fe 3+ and by drying and calcination, and then the excellent bionic hierarchical fibers iron oxide has been prepared and the performance has been further studied.…”