Photosensitive WS₂/ZnO Nano-Heterostructure-Based Electrocatalysts for Hydrogen Evolution Reaction

Abstract

Two-dimensional transition-metal dichalcogenides (2D-TMDCs) have shown great promise for sustainable energy production via electrocatalytic, photocatalytic, and photovoltaic activities. Here, we report the WS 2 /ZnO (WZO) nanoheterostructures with optimized materials properties for high-performance photoelectrocatalytic activity. WZO nanoheterostructures have shown faster electrocatalytic hydrogen evolution reaction (HER) compared to pristine WS 2 and ZnO owing to the reduced charge transfer resistance and enhanced active area of the catalysts. HER activity has been found to be stable for chrono-amperometry of 25 h and cyclic voltammetry of 2000 cycles. The catalyst has shown visible light-sensitive catalytic activity and a significantly reduced over potential of −182 mV versus RHE (reversible hydrogen electrode) at 10 mA/cm 2 . Additionally, a self-powered and fast photodetection ability with a responsivity of 6.7 mA/W, stability upto 1600 s, and response time of 80 ms has been reported. The maximum photoresponsivity of 1.34 A/W was realized at −250 mV versus RHE. Besides, present findings report the importance of dominating pyroelectricity for photoswitching. Overall, the present findings explored the photo-sensitive 2D-TMDCs as an alternative of noble metals in electrocatalytic activity for clean energy production.

Flexible Titanium Nitride/Germanium-Tin Photodetectors Based on Sub-Bandgap Absorption

“…The output current increased from 17 to 78 μA with the increasing optical powers from 0.05 to 0.58 mW due to the enhanced electron–hole generation. , The relationship between the output current and optical power can be expressed by the power law I photo ∝ P α . The slope of the sublinear fitting line was derived to be 0.65, indicating that deep level defect states reduced the photoresponse …”

“…The slope of the sublinear fitting line was derived to be 0.65, indicating that deep level defect states reduced the photoresponse. 41 We further characterized important figure-of-merits such as responsivity (R), external quantum efficiency (EQE), and detectivity (D*) to evaluate the optoelectronic performance. Responsivity is defined as the net photocurrent generated upon excitation of unit incident power.…”

Layered 2D PtX2 (X = S, Se, Te) for the electrocatalytic HER in comparison with Mo/WX2 and Pt/C: are we missing the bigger picture?

“…TMDs resemble 2D graphene in their structure and tend to have resonating properties. 30,39,[43][44][45][46][47][48][49] Very common transition metals with a stable 4+ oxidation state and a capability of forming TMDs are W, Mo, Ti, Cr, Mn, Re, Pd, and Pt. Among them, TMDs of Mo and W are the most frequently used HER electrocatalysts.…”

Synthesis and characterisation of heteroatom-doped reduced graphene oxide/bismuth oxide nanocomposites and their application as photoanodes in DSSCs

“…Semiconductor photoanode nanomaterials with a high surface area can facilitate more dye absorption, effective photon harvesting, and fast charge transport, thereby improving the PCE of DSSCs. Various approaches, such as doping, 6 surface modication, 7 and the use of hybrid semiconducting nanomaterials, [8][9][10][11][12] have been proposed to improve the properties of semiconductor materials. Semiconductor nanomaterials such as metal oxides, including titanium dioxide (TiO 2 ), 13 zinc oxide (ZnO), 14 zirconium dioxide (ZrO 2 ), 15 tungsten trioxide (WO 3 ), 16 and tin(IV) oxide (SnO 2 ), 17 have been extensively explored as photoanode materials in DSSCs.…”