Oxygen evolution catalysts by self-assembly of MS₂ (M = Mo, W) and Ni₃Fe-LDH nanosheets

Layered double hydroxides (LDHs) have been demonstrated as high-activity electrocatalysts for the oxygen evolution reaction (OER) but their performance is limited by their inherently low electrical conductivity. This can be mitigated by the formation of a hybrid material composed of transition metal dichalcogenide (TMD) layers interleaved between LDH sheets. Here, we report an improved synthesis of TMD/LDH hybrid materials using a post-synthetic aqueous miscible organic solvent treatment (AMOST) on Ni₃Fe-borate-LDH to yield predominantly mono/few-layer LDH nanosheets. These LDH nanosheets when combined with either MoS₂ or WS₂ monolayers create MoS₂/Ni₃Fe-LDH and WS₂/Ni₃Fe-LDH hybrid materials, respectively. The hybrid materials prepared in this way exhibit improved electrocatalytic performance towards the OER, with low overpotentials at 10 mA cm^-2 of 258 and 248 mV, respectively. Over 12 h chronopotentiometric testing, both hybrids show lower potential drift than pristine Ni₃Fe-borate-LDH, while separate extended measurements maintained operation at 10 mA cm^-2 for approximately 20 h.