Electrochemically deposited transition metal dichalcogenide heterostructures as electrocatalysts:Accelerated kinetics for the hydrogen evolution reaction

Transition metal dichalcogenide (TMD) heterostructures have been discovered to have improved catalytic activity towards the hydrogen evolution reaction (HER). This study explores the stability and HER catalytic activity including reaction kinetics of heterolayers of different TMDs (MoS2, MoSe2 and WS2). The stability of the heterolayers varied with those having an overlayer of electrodeposited MoS2 being more stable as compared to those with MoSe2 overlayer which degraded with each scan in acidic media. Investigation into the HER kinetics of the heterolayers involved Tafel analysis and electrochemical rate constant calculation. There was an improvement in Tafel values calculated in comparison to reported values for these heterolayers. WS2/MoS2 and MoSe2/MoS2 heterolayers registered rate constants of (3.20 ± 0.10) × 10−4 cm s−1 and (1.73 ± 0.03) × 10−4 cm s−1 respectively, which was an improvement of up to an order of magnitude compared to the reported rate constant of electrodeposited MoS2 of (3.17 ± 0.30) × 10−5 cm s−1. All this highlights the improved HER catalytic activity of the heterolayers.</p

Nanoparticle electrochemistry

This perspective article provides a survey of recent advances in nanoscale electrochemistry, with a brief theoretical background and a detailed discussion of experimental results of nanoparticle based electrodes, including the rapidly expanding field of “impact electrochemistry”.</p

Effect of catalyst carbon supports on the oxygen reduction reaction in alkaline media: a comparative study

Four common catalyst carbon supports are quantitatively compared in an integrated study towards the oxygen reduction reaction in alkaline media.</p

Modular construction of size-selected multiple-core Pt–TiO2 nanoclusters for electro-catalysis

Modular construction of platinum–titanium dioxide clusters, which exhibit multiple Pt cores with a preferred size of 30 ± 6 atoms.</p

Progress towards the ideal core@shell nanoparticle for fuel cell electrocatalysis

The commercialisation of polymer electrolyte fuel cells (PEFCs) has been hampered by the high cost of platinum metal. Due to its high durability and catalytic activity, platinum is widely used to catalyse the oxygen reduction and hydrogen oxidation reactions essential to the operation of these cells. Core@shell nanoparticles with thin layers of platinum deposited on cores composed of cheaper materials have offered an attractive route towards the reduction of overall loading of platinum, with the retention of active catalyst surface area. This review surveys approaches taken to prepare idealised active and durable core@shell nanocatalysts by tweaking core compositions. A critical reflection on the current status of the field, as well as predictions as to likely directions for future developments, are discussed as a conclusion to the review

Electrochemical sulfidation of WS2 nanoarrays:strong dependence of hydrogen evolution activity on transition metal sulfide surface composition

The activity of transition metal sulfides for the hydrogen evolution reaction (HER) can be increased by sulfur-enrichment of active metal-sulfide sites. In this report, we investigate the electrochemical sulfidation of atmospherically aged WS2 nanoarrays with respect to enhancing HER activity. In contrast to MoS2, it is found that sulfidation diminishes HER activity. Electrochemical and XPS experiments suggest the involvement of insoluble tungsten oxides in the altered HER and electron transfer properties. This demonstrates the strong dependence of the transition metal dichalcogenide (TMD) composition with the successful sulfur incorporation and subsequent HER activity