Photoreforming of waste plastic by B-doped carbon nitride nanotube: Atomic-level modulation and mechanism insights

Photoreforming waste plastics into valuable products is a promising approach, but it requires efficient, eco-friendly photocatalysts and a deeper understanding of catalytic mechanism. We have developed a B-doped g-C₃N₄ nanotube catalyst with well-defined structure for photoreforming poly(ethylene terephthalate) (PET) into valuable chemicals and H₂. This catalyst achieved a H₂ evolution rate of 3240 μmol g_catal⁻¹ h⁻¹, outperforming previous cadmium-free catalysts. It also oxidized PET to higher-value organic acids via a hole oxidation mechanism. Experimental and theoretical calculations showed that B atom doping not only greatly increased the catalyst's active sites, but also significantly accelerated the electron–hole separation and transfer rate, optimized the adsorption and activation behavior of the substrate. Using concentrated sunlight, we achieved a H₂ evolution rate of 475 μmol g_catal⁻¹ h⁻¹ for real-world PET in seawater. Techno-economic analysis suggests processing 50,000 tons of waste plastic annually could yield a profit of $7.45 million.