Orbital Hybridized MoO₃/MoSe₂ Heterojunction for Dual-Driven Interfacial Reaction and Charge Transfer Toward Enhanced Electrochemical Response

Modulation of the electronic orbital structures within heterojunctions can influence the efficiency of electrochemical catalytic processes. However, precise control of interfacial orbital hybridization in heterojunctions remains challenging because it is difficult to tune electronic states and directly correlate them with catalytic kinetics. Here, MoO₃ and MoSe₂ were integrated to form a heterojunction, wherein the orbital hybridization of Mo at the interface was tailored to regulate the electronic structure, aiming to enhance the interfacial catalytic activity during electrochemical reactions. We developed an electrochemical sensor for nitrite detection. Compared with pristine MoO₃ (227.03 μA cm^-2 mM^-1) and MoSe₂ (128.66 μA cm^-2 mM^-1), the optimized MoO₃/MoSe₂ heterojunction exhibits exceptional sensitivity of 958.53 μA cm^-2 mM^-1. Both experimental and theoretical analyses revealed that the orbital hybridization strategy in the MoO₃/MoSe₂ heterojunction effectively lowers the energy barrier of the rate-determining step in nitrite oxidation and facilitates electron transfer, thereby synergistically improving the reaction kinetics. Furthermore, the high-performance MoO₃/MoSe₂ heterojunction was successfully integrated into a portable device for nitrite detection under neutral aqueous conditions. This interfacial orbital hybridization strategy simultaneously addresses the challenges of charge carrier dynamics and interfacial energy barrier regulation, thus advancing catalyst design and improving both catalytic efficiency and sensing performance.