Journal article
Comparison of liquid exfoliated transition metal dichalcogenides reveals MoSe2 to be the most effective hydrogen evolution catalyst
Publication Details
Authors: | Gholamvand, Z.; McAteer, D.; Backes, C.; McEvoy, N.; Harvey, A.; Berner, N.; Hanlon, D.; Bradley, C.; Godwin, I.; Rovetta, A.; Lyons, M.; Düsberg, G.; Coleman, J. |
Publisher: | ROYAL SOC CHEMISTRY |
Publication year: | 2016 |
Journal: | Nanoscale |
Pages range : | 5737-5749 |
Volume number: | 8 |
Issue number: | 10 |
Start page: | 5737 |
End page: | 5749 |
Number of pages: | 13 |
ISSN: | 2040-3364 |
DOI-Link der Erstveröffentlichung: |
Abstract
While 2D transition metal dichalcogenides are known to be promising materials for electrocatalysis of hydrogen production, it is not clear which member of this family of materials is the most effective catalyst. Here we perform a comprehensive study, comparing the catalytic performance of electrodes consisting of porous arrays of liquid exfoliated MX2 nanosheets (M = Mo, W; X = S, Se, Te). We find a clear hierarchy with selenides > sulphides > tellurides with MoSe2 clearly out-performing the other materials. In all cases the performance, as characterised by current density at a given potential, can be improved by increasing the number of active sites (via control of the electrode thickness) and/or by adding carbon nanotubes to the electrode (i.e. increasing the electrode conductivity). While all materials formed reasonably stable electrodes, addition of nanotubes tended to improve mechanical cohesion. In an attempt to maximise performance, we prepared thick (similar to 15 mu m), free standing MoSe2/SWNT composite electrodes which displayed Tafel slopes of similar to 77 mV per decade and exchange current densities of similar to 0.1 mA cm(-2). These electrodes had low onset potentials, reaching -2 mA cm(-2) at -41 mV (vs. RHE) and generated high current densities of -35 mA cm(-2) at -200 mV (vs. RHE).
While 2D transition metal dichalcogenides are known to be promising materials for electrocatalysis of hydrogen production, it is not clear which member of this family of materials is the most effective catalyst. Here we perform a comprehensive study, comparing the catalytic performance of electrodes consisting of porous arrays of liquid exfoliated MX2 nanosheets (M = Mo, W; X = S, Se, Te). We find a clear hierarchy with selenides > sulphides > tellurides with MoSe2 clearly out-performing the other materials. In all cases the performance, as characterised by current density at a given potential, can be improved by increasing the number of active sites (via control of the electrode thickness) and/or by adding carbon nanotubes to the electrode (i.e. increasing the electrode conductivity). While all materials formed reasonably stable electrodes, addition of nanotubes tended to improve mechanical cohesion. In an attempt to maximise performance, we prepared thick (similar to 15 mu m), free standing MoSe2/SWNT composite electrodes which displayed Tafel slopes of similar to 77 mV per decade and exchange current densities of similar to 0.1 mA cm(-2). These electrodes had low onset potentials, reaching -2 mA cm(-2) at -41 mV (vs. RHE) and generated high current densities of -35 mA cm(-2) at -200 mV (vs. RHE).
