Piezoelectric materials have demonstrated applicability
in clean
energy production and environmental wastewater remediation through
their ability to initiate a number of catalytic reactions. In this
study, we used a conventional sol–gel method to synthesize
lead-free rhombohedral R3c bismuth
sodium titanate (BNT) particles of various sizes. When used as a piezocatalyst
to generate H2 through water splitting, the BNT samples
provided high production rates (up to 506.70 μmol g–1 h–1). These piezocatalysts also degraded the organic
pollutant methylene blue (MB, 20 mg L–1) with high
efficiency (up to k = 0.039 min–1), suggesting their potential to treat polluted water. Finally, we
found that the piezopotential caused band tilting in the semiconductor
and aided charge transfer such that recombination was suppressed and
the rate of H2 production increased. The mechanism of piezoelectric
catalysis involved oxygen vacancies, the size of the catalyst, and
the internal electric field playing important roles to enhance electron–hole
separation, which further enhanced the catalysis reactions.
The present study employed the surfactant-free growth of ultralong (∼50 μm) silver nanowires (AgNWs) with a high aspect ratio (more than 1000) by galvanic replacement.
Monolayer transition-metal dichalcogenides (TMDCs) have great potential for realizing high-performance nanoelectronic and optoelectronic devices. However, contact resistance originating from the Fermi-level pinning effect leads to high power consumption and poor photocurrent transport capability in TMDC photodetectors. Moreover, the atomically thin nature of monolayer TMDCs limits their absorption and optoelectronic performance. Here, an all-semimetal plasmonic photodetector that consists of monolayer MoS 2 integrated with Bi contact electrodes and Bi plasmonic nanodisks is presented to address these issues. By utilizing Bi as the contact metal, the Fermi-level pinning effect at the metal−semiconductor interface is suppressed, which increases the response speed and reduces the photocurrent loss to contact resistance. Furthermore, the strongly localized electromagnetic field across the interface between Bi plasmonic structures and MoS 2 enhances the photon-to-exciton conversion efficiency over 4 times at 600 nm. Photoresponsivity of this all-semimetal MoS 2 photodetector shows a 690% enhancement compared to the pristine device with conventional electrodes. In addition, the detectivity of our device reaches 6.40 × 10 12 Jones, which is the highest value reported for plasmonic MoS 2 photodetectors. This work demonstrates that integrating multifunctional semimetal with TMDCs offers a new approach to realizing high-performance and energy-efficient TMDC optoelectronic devices.
In this study, we
observed the enhanced photocatalytic activity
of a few-layer WS2/ZnO (WZ) heterostructure toward dye
degradation and H2 production. The few-layer WS2 acted as a co-catalyst that separated photogenerated electron/hole
pairs and provided active sites for reactions, leading to the rate
of photocatalytic H2 production of WZ being 35% greater
than that over the bare ZnO nanoparticles. Moreover, vortex-stirring
accelerated the mass-transfer of the reactants, leading to the efficiency
of dye photodegradation being 3 times higher than that obtained without
high-speed stirring. We observed a similar effect for H2 production, with greater photocatalytic performance arising from
the increased mass-transfer of H2 from the catalyst surface
to the atmosphere.
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