Interfacial engineering of Cu9S5@MoS2 p-n type heterojunction via in situ phase separation for highly efficient electrocatalytic oxidation of 5-hydroxymethylfurfural

In this study, a highly electrochemically active Mo-S-Cu interface connected via metal–sulfur bonds is synthesized through a Cu 9 S 5 @MoS 2 p-n type heterojunction structure. This structure is ingeniously fabricated via in situ phase separation, achieved by the pyrolytic sulfidation of individual copper molybdate. The resulting Mo-S-Cu interface effectively regulates the local electronic structure and charge distribution. Consequently, the energy band alignment of the as-prepared doped heterojunction is elevated compared to that of intrinsic MoS 2 , significantly enhancing the charge transfer ability. Utilizing this advanced Mo-S-Cu interface as an electrocatalyst, the selective electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) for the synthesis of 2,5-furandicarboxylic acid (FDCA) was successfully realized. Notably, an outstanding conversion efficiency of 94.45%, an unprecedented selectivity of 100%, and a FE of 91.13% were achieved. Furthermore, DFT calculations revealed that the successful synthesis of the Cu 9 S 5 @MoS 2 p-n type heterojunction is attributable to the low lattice mismatch rate and the high electron density in the heterometal sulfur bonds’ contact region, which can be functionalized as a catalytic center to catalyze the HMF oxidation reaction. This study offers critical insights into the preparation and application of such semiconductors, fostering the development of high-efficiency electrocatalytic systems and paving the way for advancements in materials science and the circular carbon economy.