Stoichiometry-Controlled Mo_xW_1–xTe₂ Nanowhiskers: A Novel Electrocatalyst for Pt-Free Dye-Sensitized Solar Cells

Abstract

Novel polymorphic Mo x W1–x Te2-based counter electrodes possess high carrier mobility, phase-dependent lattice distortion, and surface charge density wave to boost the charge-transfer kinetics and electrocatalytic activity in dye-sensitized solar cells (DSSCs). Here, we report the syntheses of stoichiometry-controlled binary and ternary Mo x W1–x Te2 nanowhiskers directly on carbon cloth (CC), denoted by Mo x W1–x Te2/CC, with an atmospheric chemical vapor deposition technique. The synthesized Mo x W1–x Te2/CC samples, including 1T′-MoTe2/CC, Td-WTe2/CC, Td-Mo0.26W0.73Te2.01/CC, and 1T′- & Td -Mo0.66W0.32Te2.02/CC, were then employed as different counter electrodes to study their electrochemical activities and efficiencies in DSSCs. The photovoltaic parameter analysis manifests that Mo x W1–x Te2/CCs are more stable than a standard Pt/CC in the I –/I 3 – electrolyte examined by cyclic voltammetry over 100 cycles. A 1T′- & Td -Mo0.66W0.32Te2.02/CC-based DSSC can achieve a photocurrent density of 16.29 mA cm–2, a maximum incident photon-to-electron conversion efficiency of 90% at 550 nm excitation, and an efficiency of 9.40%, as compared with 8.93% of the Pt/CC counterpart. Moreover, the 1T′- & Td -Mo0.66W0.32Te2.02/CC shows lower charge-transfer resistance (0.62 Ω cm2) than a standard Pt/CC (1.19 Ω cm2) in electrocatalytic reactions. Notably, Mo x W1–x Te2 nanowhiskers act as an electron expressway by shortening the path of carrier transportation in the axial direction from a counter electrode to electrolytic ions to enhance the reaction kinetics in DSSCs. This work demonstrates that the nanowhisker-structured 1T′- & Td -Mo0.66W0.32Te2.02/CC with high carrier mobility and robust surface states can serve as a highly efficient counter electrode in DSSCs to replace the conventional Pt counter electrode for electrocatalytic applications.

Assessing Challenges of 2D-Molybdenum Ditelluride for Efficient Hydrogen Generation in a Full-Scale Proton Exchange Membrane (PEM) Water Electrolyzer

“… 32 Moreover, thin-film growth technology is a highly automated process, and thus, it could warrant the quality and reliability of electrolyzer devices based on metallic 1T′-MoTe 2 thin films compared with sprayed interfaces. Recent successes in fabrication of 1T′-MoTe 2 films on CC 33 , 34 demonstrated that large film areas (imperative for electrolyzer applications) are achievable. This enables a pivotal shift to rigorous evaluation of the films in industrially relevant full-scale flow-cell PEM electrolyzers.…”

Synergistic NiO/Fe2O3 heterostructure-enhanced electrocatalytic performance in dye-sensitized solar cells

“…[5][6][7] In addition, it has received considerable attention owing to its straightforward design and affordable price. 8,9 In general, photoanode, counter electrode (CE), and electrolyte are the three main components in DSSCs, of which CE is mainly used to collect and transfer external circuits, thus catalyzing the reduction of I 3 − on the interface between CE and electrolyte. [10][11][12] Commercially, Pt is generally considered the benchmark for CE, but the high cost and lack of availability restrict its wide usage.…”