Tunable Heteroassembly of 2D CoNi LDH and Ti3C2 Nanosheets with Enhanced Electrocatalytic Activity for Oxygen Evolution

Abstract

The sluggish kinetics of oxygen evolution reaction (OER) are bottlenecks to develop hydrogen energy based on water electrolysis, which can be significantly improved using high performance catalyst. In this context, the CoNi layered double hydroxide (LDH)/Ti3C2 heterostructures are obtained using electrostatic attraction of the positively charged LDH and negatively charged Ti3C2 nanosheets as catalyst to optimize the OER performance. Such alternately stacking exhibits good catalytic activity with a lower overpotential and a small Tafel slope, outperforming their individual components. The results by density functional theory (DFT) simulation find that the charge transfers from Ti3C2 to CoNi LDH, not only adjust the electron distribution, but also increase the electron density of the interfacial active sites, thus enhances the electron transfer efficiency inside the heterostructures. Moreover, the Co2+ and Ni3+ ions exhibit a synergistic effect in supplying more electrons to adsorb the adjacent intermediates with the active hydrogen and oxygen vacancies, to improve the adsorption capability and reduce the reaction energy barriers. These findings provide a rewarding avenue towards the design of highly efficient electrocatalysts for OER.