Tunable Pt–MoS_x Hybrid Catalysts for Hydrogen Evolution

Abstract

Platinum (Pt)-based materials are inevitably among the best-performing electrocatalysts for hydrogen evolution reaction (HER). MoS was suggested to be a potent HER catalyst to replace Pt in this reaction by theoretical modeling; however, in practice, this dream remains elusive. Here we show a facile one-pot bottom-up synthesis of Pt-MoS composites using electrochemical reduction in an electrolytic bath of Pt precursor and ammonium tetrathiomolybdate under ambient conditions. By modifying the millimolar concentration of Pt precursors, composites of different surface elemental composition are fabricated; specifically, PtMoS, PtMoS, PtMoS, and PtMoS. All electrodeposited Pt-MoS hybrids showcase low overpotentials and small Tafel slopes that outperform MoS as an electrocatalyst. Tantamount to electrodeposited Pt, the rate-limiting process in the HER mechanism is determined to be the Heyrovsky desorption across Pt-MoS hybrids and starkly swings from the rate-determining Volmer adsorption step in MoS. The Pt-MoS composites are equipped with catalytic performance that closely mirrors that of electrodeposited Pt, in particular the HER kinetics for PtMoS and PtMoS. This work advocates electrosynthesis as a cost-effective method for catalyst design and fabrication of competent composite materials for water splitting applications.

Benchmarking the Activity, Stability, and Inherent Electrochemistry of Amorphous Molybdenum Sulfide for Hydrogen Production

“…The edge sites‐driven hydrogen electroadsorption properties of TMDs have prompted the fabrication of amorphous molybdenum sulfide materials (MoS x ) to minimize exposure of the electrocatalytically inert MoS 2 basal planes for multiple applications . A simple, yet scalable method to fabricate MoS x has been reported by substrate‐insensitive electrodeposition from a [MoS 4 ] 2− precursor, and critical properties in MoS x materials such as film thickness, morphology, Mo:S stoichiometry, as well as incorporation of dopants or nanocomposite formation, have been easily tuned by experimental parameters.…”

Transition Metal Dichalcogenides for the Application of Pollution Reduction: A Review

“…Numerous works have discovered ways to enhance the HER performance of MoS 2 . Just to name a few, these works proposed to improve the HER activity by (i) coating the MoS 2 with metals (e.g., palladium [64], aluminum [65], gold [66], platinum [67], etc. ); (ii) using a novel electrochemical approach to deposit the MoS 2 nanosheet [68]; (iii) introducing the use promising support for the MoS 2 nanoparticles (e.g., multi-wall carbon nanotubes [69]); (iv) varying the choice of dispersion media used [70]; and (v) coupling with other electrocatalysts (e.g., molybdenum carbide [71]).…”

Strongly enhanced visible light photoelectrocatalytic hydrogen evolution reaction in an n-doped MoS2 /TiO2(B) heterojunction by selective decoration of platinum nanoparticles at the MoS2 edge sites

“…It may be noted that though there are several reports on the catalytic activity of binary MoS 2 /Pt and TiO 2 /Pt system, there is hardly any report on the TiO 2 /MoS 2 /Pt composite system. 4,[41][42][43] Very recently, photocatalytic and electrocatalytic H 2 generation in a TiO 2 /Pt/MoS 2 composite system was reported by Li et al 44 However, the system was not well characterized and the performance of the composite system was comparable or inferior to that of binary systems. Unlike the earlier reports, we have chosen a porous TiO 2 (B) nanobelt as a novel platform for the growth of edge site exposed few-layer MoS 2 .…”