Anandha Krishnan Ramasamy, A. Tamilselvan, Govindaraj Rajamanickam, Balamurugan Rathinam
The half reaction of oxygen evolution reaction (OER) has slow kinetics compared to the other reactions of hydrogen evolution reaction (HER) in electrocatalyst-based water splitting (WS) for hydrogen production. To improve the WS by an electrocatalyst, the use of spinel oxide based heterostructure (HS) catalysts supported by a carbon material is considered as a cost-effective strategy for the application of OER over noble metal catalysts. Here, for the first time, a novel WO 3 /NiCo 2 O 4 heterostructure coupled with MWCNT was synergistically interface engineered via an ultrasonication-assisted hydrothermal synthesis method to achieve an efficient electrocatalyst based oxygen evolution reaction (OER) due to their significant electrochemical activity of HS. The rational integration of WO 3 and redox-active NiCo 2 O 4 with the highly conductive MWCNT framework results in a hierarchically porous heterointerface that promotes improved charge carrier transport, enhanced active site accessibility, and synergistic conductivity. The electrochemical results demonstrate the reduced overpotential of 323 mV at 10 mA cm –2 for MWCNT@WO 3 /NiCo 2 O 4 with a Tafel slope of 123 mV dec –1, a reduced charge transfer resistance of 2.5 Ω, and a large electrochemical double-layer capacitance of 48.9 mF cm –2, outperforming its individual and WO 3 /NiCo 2 O 4 counterparts. Improved reaction kinetics, reduced energy barriers, and superior electrochemical durability of over 38 h underscore the effectiveness of this interface engineering strategy. These findings highlight the promise of MWCNT@WO 3 /NiCo 2 O 4 as a cost-effective, high-performance heterostructure for OER electrocatalysis in integrated water splitting and sustainable oxygen evolution reactions.