A “honeycomb” heterostructured α-MnO2 nanowire/NiCo2O4 hollow nanocages with superior photoelectrocatalytic performance for water purification

Recently, employing photoelectrocatalysis (PEC) strategy to eliminate environmental impact and hazards of hard-to-handle antibiotics such as sulfamethoxazole (SMX) has been given increasing attention. Herein, a “honeycomb” heterostructured α-MnO 2 nanowire/NiCo 2 O 4 hollow nanocages PEC catalyst is fabricated by using a continuous assembly process as following: (1) construction of α-MnO 2 nanowire carrier, (2) surface adhesion of ZIF-67, and (3) Co/Ni ion exchange. The as-synthesized Ti/α-MnO₂@NiCo₂O₄ demonstrated excellent PEC performance for degrading SMX, as compared with that of α-MnO 2 , α-MnO 2 @ZIF-67. Especially, the optimized Ti/α-MnO₂@NiCo₂O₄-30 showed removal rate of 98.2 % for SMX in 30 min, outstanding durability (~8000 s), and tolerable reusability (the removal rate can still reach 76.5 % for SMX after five cycles). The improvement of PEC performance for Ti/α-MnO₂@NiCo₂O₄ can be attributed to that the unique porous structure formed numerous electrochemically active sites, and the α-MnO₂ nanowire as common channel for charge transfer promoted the migration of induced carriers. The DFT calculation indicated that a II-scheme heterojunction can be formed over the α-MnO 2 @NiCo 2 O 4 composite, which can effectively inhibit the recombination of induced carriers, facilitate the degradation process. This work provides a valuable approach for constructing nanohybrids with targeted functionalities, opening new possibilities for the application of nanomaterials in wastewater treatment.