Bifunctional electrocatalytic water splitting augmented by cobalt-nickel-ferrite NPs-supported fluoride-free MXene as a novel electrocatalyst

• Acid-free wet chemical synthesis of a highly stable CoNiFe 2 O 4 @MXene electrocatalyst . • Inserted NPs engaged the delaminated MXene to show a high surface area . • Layer-by-layer assembly was adopted to prevent restacking in MXene . • A stable catalyst that needs only 1.58 V at 10 mA/cm 2 for water splitting. • Tafel slopes of 36 and 45 mV/dec was achieved for HER and OER . Electrocatalytic water splitting is a promising approach for the massive production of hydrogen as an environmentally compatible and renewable energy alternative to fossil fuels. The development of an active, stable, low-cost, and bifunctional electrocatalyst , in this regard, is a big challenge to achieve the desired electrocatalytic hydrogen/oxygen production via water splitting. MXene (Ti 3 C 2 T x ) has recently been explored as an excellent candidate for electrocatalytic water splitting. However, its poor stability, hazardous synthesis routes, and the restacking of its flakes are the major bottlenecks in its effective application as an electrocatalyst . Herein, we adopted an acid-free wet chemical approach to synthesize MXene and its composites with CoNiFe 2 O 4 for efficient water splitting. We proposed a novel layer-by-layer (LBL) assembly approach to obtain a CoNiFe 2 O 4 /MXene-based 2D/NPs/2D network and prevented restacking in MXene flakes for efficient electrocatalysis. The inserted NPs via the LBL approach engaged the delaminated MXene flakes, which results in a high surface area and active sites for water splitting. The fabricated catalyst showed excellent overpotentials of 149 and 17 mV at 10 mA/cm 2 for water splitting via OER and HER . In addition, the Tafel slope of 36 and 45 mV/dec was achieved for HER and OER along with high electrochemical stability upto 100 h, which surpassed many similar catalysts that were recently reported in the literature. This study provides insights into the design of multicomponent low-dimensional electrocatalysts for water splitting.