Concurrent photoreforming of polyethylene into commercial chemicals and hydrogen generation utilizing g-C3N4/Co3O4 Z-scheme heterostructure: A waste-to-wealth concept

Polyethylene plastic bags end up in landfills where they take around 300 years to photodegrade and are difficult to recycle. They decompose into minute poisonous particles that pollute the land and streams and make their way into the food chain when animals eat them by mistake. To tackle these huge amounts of waste photoreforming process offers a simple and economical way that works at ambient conditions to produce value-added products through waste degradation and generate hydrogen (H2) via the water reduction process. Our research aims to produce effective catalysts by synthesizing cobalt oxide (Co3O4) on graphite carbon nitride (g-C3N4) layers to build a g-C3N4/Co3O4 Z-scheme hybrid using a green hydrothermal in situ synthetic technique. Specifically, this catalyst was used for forming a Z-scheme heterostructure composite which greatly enhances the photocatalytic performance of the catalysts when exposed to the visible range of light. From the morphological analysis, it was seen that Co3O4 nanoparticles are beautifully spread over g-C3N4 sheets making the composite stable and effective for catalytic applications. From the quenching experiment, it was found that the hydroxyl (•OH) and superoxide radicals (•O2‾) are responsible for the photocatalytic behaviour of the as-prepared Z-scheme catalyst. Using this composite, the photoreforming activity of the catalyst for the disintegration of polyethylene to create organic compounds and hydrogen (H2) at an evolution rate of 17249 μmol g−1 h−1 was investigated. The results obtained in photoreforming experiments to produce energy and value-added products using polyethylene as substrate are challenging as only a visible light source was used for the tests that degraded the polyethylene in only 6 h of irradiation. This result is far better than the others in comparison to the time, catalyst type, and light source. Through using the method reported herein, a promising photocatalyst for green and sustainable development can be designed.