Anchoring Co3O4 nanoparticles on conjugated polyimide ultrathin nanosheets: construction of a Z-scheme nano-heterostructure for enhanced photocatalytic performance

Abstract

Efficient utilization of solar energy for photocatalytic hydrogen production and degradation of organic pollutants is one of the most promising approaches to solve the energy shortage and environmental pollution. A series of Co₃O₄/sulfur-doped polyimide (CO/SPI) direct Z-scheme nano-heterostructure photocatalysts was successfully prepared via a facile green thermal treatment method. The effects of Co₃O₄ nanoparticles on the structure, morphology, and optoelectronic properties of CO/SPI composite samples were systematically characterized by different spectroscopic methods. Characterization results confirmed that Co₃O₄ nanoparticles as an acid oxide catalyst promoted the oxidation stripping of bulk SPI to form SPI ultrathin nanosheets. Thus, the Co₃O₄ nanoparticles were firmly embedded on SPI ultrathin nanosheets to construct a direct Z-type CO/SPI nanostructure junction. Therefore, the activity and cycle stability of photocatalytic water splitting for hydrogen production and organic pollutant degradation were greatly improved under solar light irradiation. In particular, the 0.5CO/SPI composite sample displayed the highest activity with an average production rate of 127.2 μmol g⁻¹ h⁻¹, which is nearly 13 times and 106 times higher than that of SPI and Co₃O₄. This work provides a new avenue for constructing efficient inorganic–organic nanoheterostructured Z-type photocatalysts and takes an important step towards the efficient utilization of renewable energy.