The Substrate Morphology Effect for Sulfur-Rich Amorphous Molybdenum Sulfide for Electrochemical Hydrogen Evolution Reaction

Abstract

Amorphous molybdenum sulfide (MoSx) is a promising material for hydrogen evolution reaction (HER) due to its nearly zero hydrogen adsorption free energy at the sulfur (S) edge-sites. To prepare more efficient MoSx-based electrocatalysts, new attempts are required to increase the exposure of the MoSx lateral size and, therefore, increase the S atom's contents. The majority of studies reported in the literature investigate MoSx over conductive substrates. However, MoSx can be electrodeposited over inexpensive and chemically stable platforms, such as semiconductors. This work presents the semiconductor substrate morphology effect for prepared sulfur-rich MoSx for electrochemical hydrogen evolution reaction. The electrodes are prepared by cyclic voltammetry with 25 cycles over TiO2 film and TiO2 nanotubes (TiO2NT) substrates. The MoSx deposit on TiO2NT presents an increase S atoms contents and exhibits excellent HER activity with a low overpotential of -93±7.5 mV to reach -10 mA cm-2 and a higher exchange current density equal to 91 µA cm-2, and a smaller Tafel slope of 43 mV dec-1.

Direct Z‐scheme among Niobium Pentoxide and Poly(heptazine imide) for NH3 Photoelectrosynthesis under Ambient Conditions

“…The small semicircle refers to the resistance and pseudo‐capacitance of the charge transfer process [33,34] . A larger radius indicates higher R ct values, and, in the sample with and without PHI, it was found to be 248.66 and 159.86 Ω cm −2 , respectively.…”

“…The small semicircle refers to the resistance and pseudocapacitance of the charge transfer process. [33,34] A larger radius indicates higher R ct values, and, in the sample with and without PHI, it was found to be 248.66 and 159.86 Ω cm À 2 , respectively. Unlikely other polymeric semiconductors, PHI did not present good electrical conductivity even under light, which justifies the increase in R ct , in addition to a possible surface area reduction, as the PHI deposition covers the surface of the nanotubes.…”

Recent Advances in Layered MX2-Based Materials (M = Mo, W and X = S, Se, Te) for Emerging Optoelectronic and Photo(electro)catalytic Applications

“…While graphene exhibits a gapless band structure [7], in particular, 2H-MoS 2 can tune its band structure by simply adjusting the number of packed layers along the basal direction [103]. Like other TMDC materials, MoS 2 features inert basal planes and active sulfur edge-sites, and increasing the density of these ligands can enhance both their chemical and electronic properties [104][105][106][107]. The intrinsic properties of layered MoS 2 are dependent on its layer number and it could be related to the reduction in vdW interactions, which is one of the main reasons why this dichalcogenide-layered material is of great interest [108].…”

Unraveling Hydrogen Adsorption on Transition Metal-Doped [Mo3S13]2– Clusters: Insights from Density Functional Theory Calculations

“…Despite the great efficiency of Pt and its derivatives in HER as well as the water-splitting process, , their scarcity and high cost necessitate the exploration of alternative materials that can meet performance requirements, cost-effectiveness, and reduced processing time. Among potential candidates, nanostructured molybdenum sulfide (MS) configurations have garnered attention due to their higher density of active sites compared to other materials. − Particularly, the amorphous structure constructed by [Mo 3 S 13 ] 2– clusters with its triangular framework consisting of three bridging, three-terminal, and one apical S has shown promising potential as the most active form in the HER catalysis among various MS configurations. − While considerable efforts have been made to enhance the MS catalytic activity by employing TM dopants as an intriguing strategy, the underlying interaction between hydrogen atoms and the MS catalyst with specific active sites has not yet been fully understood. For instance, experimental results combined with density functional theory (DFT) calculations indicated that HER is hindered by the bond between Co-dopant and MoS 2 , but is improved when Co is replaced with Ni .…”