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Enhanced sensor life using UV treatment of sulphur poisoned Pt-PtOx
摘要： In this work, we report a novel method for recovery of sulphur poisoned platinum/platinum oxide (Pt-PtOx) core-shell nanowire sensor using UV irradiation. The optimum core to shell thickness ratio and the operating conditions are the key factors to achieve a high-performance H2S sensor, described in this report. The fabricated core-shell nanowire sensor demonstrated response of 6.4% at 1 ppm H2S with detection limit of 10 ppb at 150°C operating temperature. The sensor undergoes prominent time-dependent poisoning at H2S exposure of 3 ppm when operated at 150°C due to sensor surface contamination by sulphur, later confirmed by XPS analysis. Ultraviolet light at two wavelengths, 365 nm, and 248 nm is investigated to recover the poisoned Pt-PtOx surface. UV irradiation at 248 nm for 5 minutes results in sensor recovery, confirmed by further H2S sensing characterization and XPS studies on the recovered sensor. To the best of our knowledge, this is one of the first reports on UV irradiation for recovery of sulphur poisoned metal-oxide surfaces.
关键词： sulphidation,recovery,plasma oxidation,UV irradiation,core-shell nanowire
更新于2025-09-23 15:23:52
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Controlling Silver Ion Release from Ag-Based Nanocoatings by Plasma Surface Engineering
摘要： Environmental surfaces have been widely recognized as an important source of hospital-associated transmissions. A number of silver-based antibacterial coatings have been reported in the literature. However, the success of any antibacterial strategy depends on the ability to control the kinetics of the silver ions released from the coating. The novel strategy proposed in this work is based on plasma surface engineering for a controlled-release of silver ions. Plasma-based nanocoatings, plasma oxidation processes and surface patterning of silver coatings were designed and optimized. Surface analyses such as XPS and AFM, as well as silver ion release over 168 h, was evaluated by MIP-AES. Results showed that surface plasma engineering successfully allow tuning the silver release and bioactivity in Ag-containing antibacterial coatings.
关键词： diamond-like carbon,plasma oxidation,silver release,antibacterial activity
更新于2025-09-23 15:22:29
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Nanodisc decorated W-WOx suspended nanowire: A highly sensitive and selective H2S sensor
摘要： In this work we report room temperature synthesis of plasma oxidized, suspended tungsten-tungsten oxide (W-WOx) core-shell nanowire for sensing ppb level H2S. The electric field modulation at the W-WOx interface of the core-shell nanowire strongly influences the sensing performance and brings down the operating temperature all the way down to 50°C, compared to completely oxidized (WOx) nanowire. The optimum interface ratio (W/WOx) of the nanowire shows response of 90.4% (1 ppm) with 6 months of response stability and excellent selectivity. The limit of detection of 10 ppb with response and recovery time of 4 s and 46 s respectively is achieved. To enhance the response further, we utilize nanostructuring on top of nanowire, using nanodiscs of 20 nm, 50 nm and 100 nm diameter and 10 nm height. The nanowire with nanodiscs of 20 nm diameter shows the high repeatable response of 12529% (1 ppm) at 150°C and fast response and recovery times of 12 s and 19 s with detection limit of 0.5 ppb. As we switch from unpatterned to patterned nanowire the observed change in H2S sensing characteristics, indicates that the core-shell nanowire behaviour makes a transition from p-type to n-type. Extensive material characterization is done using UV-Vis spectroscopy, XPS and TEM.
关键词： plasma oxidation,selectivity,Core-shell nanowire,nanodiscs,suspended
更新于2025-09-09 09:28:46