Porosity‐Engineering of MXene as a Support Material for a Highly Efficient Electrocatalyst toward Overall Water Splitting

The use of 2 D transition metal carbide MXenes as support materials to incorporate catalytically active compounds is of interest because of their unique properties. However, the preparation of well-dispersed catalytic phases on the inter-connected porous MXene network is challenging and has been rarely explored. This work focuses on the synthesis of basal-plane-porous titanium carbide MXene (ac-Ti3 C2 ) that is used subsequently as an effective host for the incorporation of a known catalytically active phase (IrCo) as an effective bifunctional electrocatalyst toward water splitting. The porous ac-Ti3 C2 with abundant macro/meso/micropores is prepared by a wet chemical method at room temperature and provides ideal anchor sites for intimate chemical bonding with alien compounds. The resulting IrCo@ac-Ti3 C2 electrocatalyst exhibits an excellent reactivity (220 mV at 10 mA cm-2 ) towards the oxygen evolution reaction in 1.0 m KOH, which surpasses that of the benchmark RuO2 , a low voltage cell of 1.57 V (@ 10 mA cm-2 ) and good long-term durability. Our work demonstrates the effectiveness of porosity engineering in MXene nanosheets as a support material to shorten ion migration pathways, to increase electrolyte accessibility between inter-sheets and to overcome inherited re-stacking and aggregation issues.