A marine vessel designed for the collection, shredding, and pelletizing of oceanic plastic waste. The vessel uses renewable energy sources such as solar panels and wind turbines to power onboard systems, including AI-enhanced sensors that detect and target high-density areas of plastic debris. Once collected, the plastic is shredded and processed into uniform plastic pellets optimized for use in plastic asphalt production. The vessel also includes storage compartments for the pellets and a crane system for transferring containers filled with pellets to adjacent vessels or shore-based transport. This integrated system addresses inefficiencies in traditional ocean cleanup methods by enabling immediate onboard processing, reducing transportation needs, and repurposing plastic waste into a valuable industrial resource, while significantly minimizing environmental impact through sustainable energy use.

In one aspect, the disclosure relates to methods for converting a plastic, e.g., a waste plastic into value-added products, the method including the steps of (a) contacting the waste plastics with a catalyst to form a reaction mixture and (b) applying microwave irradiation to the reaction mixture, thereby forming the disclosed value-added products such as hydrogen and a carbon product, e.g., a carbon nanomaterial such as a carbon nanotube and/or a carbon nanofiber. A method for producing essentially Cox-free hydrogen gas is also disclosed.