NiCoP cocatalyst modified g-C3N4 as ohmic junction photocatalyst for efficient degradation of tetracycline under visible light

Increasing the electron-hole recombination rate in g-C3N4 can effectively improve its photocatalytic performance. In this work, NiCoP/g-C3N4 (NCP/PCN) composites with ohmic junction were formed by embedding granular NiCoP in irregularly porous g-C3N4. There was almost no barrier between the metal and the semiconductor in ohmic junction, which made it easier for electrons to slip from PCN to NCP along the curved energy band, and NCP acted as an electron collector to rapidly capture the slipping electrons. In addition, porous g-C3N4 prepared by supramolecular self-assembly could provide a shorter diffusion path for electrons. Thus, the electron-hole was effectively separated and the photocatalytic performance was improved. The band electronic structure and existence of ohmic junction in 7-NCP/PCN composite were demonstrated by XPS, ESR and DFT calculation. Finally, a reasonable photocatalytic degradation mechanism and possible tetracycline degradation path were proposed. This work has significant potential for providing an effective method for the design of non-precious metal photocatalysts. [Display omitted] •NiCoP/g-C3N4 composites with coral-like porous structure are successfully prepared.•Ohmic junction improved the utilization efficiency of charge and redox capacity.•NiCoP acted as an electron catcher to promote the separation rate of electron-hole.•NiCoP/g-C3N4 composites showed excellent photocatalytic activity in TC degradation.•Photocatalytic mechanism of TC degradation of NiCoP/g-C3N4 composites was proposed.