Integral 2D/3D structured CoSnO3@MXene/NF as a highly active and stable bifunctional electrocatalyst for alkaline water splitting

The pursuit of efficient electrocatalysts for water electrolysis is crucial to advancing the utilization of hydrogen energy. Herein, we designed a robust and active electrocatalyst through synergistically integrating CoSnO3 nanostructures onto a highly conductive and stable 2D/3D constructed substrate (MXene sheets decorated Ni Foam) without polymer binders. Synergistically, CoSnO3 demonstrates remarkable bifunctional catalytic activity and stabilizes MXene against spontaneous oxidation. MXene acts as supporting material, enhancing electrical conductivity and preventing aggregation of CoSnO3. Strong interfacial electronic coupling between the catalyst-substrate significantly facilitates the redistribution of electrons at the interfaces of CoSnO3 and MXene. The CoSnO3@MX/NF(2:1) electrocatalyst achieves overpotentials of 274/387 and 108/376 mV at current densities of 10/500 mA cm−2 for OER and HER, respectively. In a two-electrode water electrolyzer, it delivers a cell voltage of 1.52 V at 10 mA cm−2 and good stability of over 24 h at both 100 and 300 mA cm−2, signifying outstanding performance for water splitting reactions.