Facile Fabrication of Amorphous Molybdenum Oxide as a Sensitive and Stable SERS Substrate under Redox Treatment

Abstract

Amorphous MoO3−x nanosheets were fabricated by the room‐temperature oxidation of molybdenum powder with H2O2, followed by light‐irradiation reduction in methanol. When applied as a substrate for surface‐enhanced Raman spectroscopy (SERS), these nanosheets exhibit higher sensitivity than the crystalline counterpart for a wide range of analytes. Moreover, the SERS activity remains stable on repeated oxygen insertion/extraction. In contrast, the performance of crystalline MoO3−x continuously deteriorates on successive redox treatments. This unique SERS activity allows the recycling of the substrate through an H2O2‐based Fenton‐like reaction. More importantly, the non‐invasive SERS was unprecedentedly used for the self‐diagnosis of amorphous MoO3−x as a more selective photocatalyst than its crystalline counterpart.

Smart design of high‐performance surface‐enhanced Raman scattering substrates

“…Amorphous phase refers to a substance with irregular shape, no fixed melting point, and no long‐range order in its internal structure, but a structurally ordered arrangement within a small range of distances between several atoms. Surprisingly, amorphous phases exhibit excellent SERS activity owning to its abundant metastable electronic states 111 . Our group designed the porous amorphous ZnO nanocages ( a ‐ZnO NCs) with excellent size uniformity and shape regularity in 2017.…”

Recent progress in SERS monitoring of photocatalytic reactions

“…[24][25][26][27] Fortunately, recent advancements in advanced nanostructure fabrication techniques have significantly enhanced the sensitivity of non-plasmonic metal SERS substrates. [28][29][30][31][32][33] At present, there is a growing focus on the potential for achieving in situ photocatalytic monitoring using these substrates, 32,33 although further efforts are needed to establish its routine and analytical usage. In a well-conceived SERS/photocatalytic system, the fingerprint information obtained from SERS analysis can provide profound insights into the fundamentals of photoexcited processes occurring on photocatalysts.…”

Semiconductor Enhanced rGO/Ag0/ZnO Ternary Hybrid Revealing Charge Transfer Enhancement in SERS Detection of Raman Reporter Molecules

“…Since the plasmons in them are in the infrared regions, the contribution from semiconductor components in the SERS substrate is due to chemical enhancement by the charge transfer. [3,19,20,21,22,23,24,25] In this study, we have investigated the SERS enhancement in rGO/Ag 0 /ZnO ternary hybrid substrates with different concentrations of ZnO. The motivation towards the development of a ternary hybrid is that, the individual constituent of it has a distinct function towards a potential SERS substrate viz, (i) silver nanoparticles contribute toward electromagnetic enhancement, (ii) Graphene nanostructures facilitate the fluorescence quenching as well as the binding of analyte molecules due to its characteristic π network and thereby favor the chemical enhancement and, (iii) semiconductor zinc oxide structure to enhance the signal by the charge transfer mechanism.…”

“…Many studies reveal that nanostructured semiconductor materials like TiO 2 , SnO 2, ZnO and MoO 3 also have the potential to serve as a substrate for SERS detection techniques. Since the plasmons in them are in the infrared regions, the contribution from semiconductor components in the SERS substrate is due to chemical enhancement by the charge transfer [3,19,20,21,22,23,24,25] …”