The various non-precious metal oxides and their hierarchical nanostructures have been synthesized and studied for water-splitting applications. However, the investigation of the inverse hierarchical growth of these nanostructures one over the other and their electrochemical properties is needed to be explored to design the electrocatalyst exhibiting high performance. Herein, we have synthesized CoS₂@NiCo₂O₄ and NiCo₂O₄@CoS₂ and investigated the effect of nanostructures growth in inverse order on their electrocatalytic performance for overall water splitting. The synthesis and inversion of hierarchy is confirmed through XRD, SEM, EDX, TEM and Raman spectroscopy. The interaction of water with the nanostructures is studied through contact angle analysis. The CoS₂@NiCo₂O₄ nanostructure hierarchy exhibited lower overpotential and charge transfer resistance than NiCo₂O₄@CoS₂, while the latter experiences better stability for hydrogen evolution reaction (HER) and a relatively larger electrochemically active surface area (ECSA). This manuscript provides insight to understand how the hierarchy of different components in a composite could be utilized to improve material performance while keeping the same chemical composition.

各种非贵金属氧化物及其分层纳米结构已被合成并研究用于水分解应用。然而，需要探索这些纳米结构彼此之间的逆分层生长及其电化学性质，以设计表现出高性能的电催化剂。在此，我们合成了CoS ₂ @NiCo ₂ O ₄和NiCo ₂ O ₄ @CoS ₂，并研究了纳米结构逆序生长对其整体水分解电催化性能的影响。通过 XRD、SEM、EDX、TEM 和拉曼光谱证实了层次结构的合成和反演。通过接触角分析研究水与纳米结构的相互作用。CoS ₂ @NiCo ₂ O ₄纳米结构层次结构表现出比NiCo ₂ O ₄ @CoS ₂更低的过电势和电荷转移电阻，而后者具有更好的析氢反应（HER）稳定性和相对更大的电化学活性表面积（ECSA） 。该手稿提供了深入了解如何利用复合材料中不同成分的层次结构来提高材料性能，同时保持相同的化学成分。