Engineering MoSe₂/WS₂ Hybrids to Replace the Scarce Platinum Electrode for Hydrogen Evolution Reactions and Dye-Sensitized Solar Cells

Abstract

In recent times, two-dimensional transition-metal dichalcogenides (TMDs) have become extremely attractive and proficient electrodes for dye-sensitized solar cells (DSSCs) and water electrolysis hydrogen evolution as alternatives to the scarce metal platinum (Pt). The active TMD molybdenum selenide (MoSe2) and tungsten disulfide (WS2) are inspiring systems owing to their abundance of active sulfur and selenium sites, but their outputs are lacking due to their inactive basal planes and ineffective transport behavior. In this work, van der Waals interrelated MoSe2/WS2 hybrid structures were constructed on conducting glass substrates by chemicophysical methodologies. For the first time, the constructed MoSe2/WS2 structures were effectively used as a counter electrode for DSSCs and an active electrode for hydrogen evolution to replace the nonabundant Pt. The assembled DSSCs using the designed MoSe2/WS2 heterostructure counter electrode provided a superior power-conversion efficiency of 9.92% and a photocurrent density of 23.10 mA·cm–2, unmatchable by most of the TMD-based structures. The MoSe2/WS2 heterostructure displayed excellent electrocatalytic hydrogen evolution behavior with a 75 mV overpotential to drive a 10 mA·cm–2 current density, a 60 mV·dec–1 Tafel slope, and an over 20 h durable process in an acidic medium. The results demonstrated the advantages of the MoSe2/WS2 hybrid development for generating interfacial transport and active facet distribution and enriching the electrocatalytic activity for DSSCs and the water-splitting hydrogen evolution process.

Highly Active Mo2C@WS2 Hybrid Electrode for Enhanced Hydrogen Evolution Reaction

“…Figure 5f explores phase profile of WS 2 (002) lattice direction with a spacing of 0.615 nm. The perceived highly interfaced fingerprint structures with the vertically aligned nano-stripes would be greatly supported to achieve the improved electrochemical characteristics [17,31].…”

Van der Waals Heterostructures—Recent Progress in Electrode Materials for Clean Energy Applications

“…van der Waals heterostructures have shown their capability as possible electrode materials and electrocatalysts. van der Waals heterostructures have been shown to catalyze HER, ORR, and OER much better than their 2D counterparts owing to their unique electrochemical properties, and in some cases, rivaling precious metal catalysts, such as platinum and iridium [7,33,41,42,[48][49][50]. Graphene and MoS 2 based van der Waals heterostructures have shown particular promise as a trifunctional catalyst of all three reactions [41].…”

“…The 1T-MoS 2 /20 wt.% C 60 structures also showed great stability that suppressed that of conventional Pt/C in the same experimental conditions (Figure 7f, [49]). Non-graphene-based van der Waals heterostructures consisting of molybdenum and tungsten dichalcogenides layers have also been examined as possible HER catalysts [7,51]. The rate-determining step is the absorption of hydrogen onto active sites of the catalyst [52], which is directly tied to the Gibbs free energy associated with the process.…”

“…Within the interlayer, the Gibbs free energy of each active site was noticeably reduced to 0.20 eV for S1 and 0.24 eV for S2, showcasing the structure's catalytic potential [51]. Very recently, a MoSe 2 /WS 2 heterostructure was synthesized by Vikraman et al using a dual preparation method of chemical bath and chemical vapor deposition (CVD) [7]. MoSe 2 sheets were deposited on ultrasonically etched conducting fluorine-doped tin oxide (FTO) within a chemical bath.…”

“…Climate change caused by rising global carbon emissions has driven the need for greener sources of energy and high-performance energy storage systems [1][2][3][4][5]. Commercial metal-air batteries, metal-ion batteries, proton exchange membrane fuel cells (PEMFCs), and electrolyzers rely on precious metals, such as palladium, iridium, lithium, and platinum, to drive their internal processes [6][7][8]. Rising costs, limited worldwide reserves, and geopolitical instability in dominant mining regions all severely decrease the viability of precious metal reliant energy storage systems to fulfill large-scale power grid roles [9][10][11].…”