With over 8 billion tons of plastic produced since 1950, polymers represent one of the most widely used – and most widely discarded – materials. Ambient-temperature photoreforming offers a simple and low-energy means for transforming plastic waste into fuel and bulk chemicals, but has previously only been reported using precious-metal- or Cd-based photocatalysts. Here, an inexpensive and non-toxic carbon nitride/nickel phosphide (CNx|Ni2P) photocatalyst is utilized to successfully reform polyethylene terephthalate (PET) and polylactic acid (PLA) to clean H2 fuel and a variety of organic chemicals under alkaline aqueous conditions. Ni2P synthesized on cyanamide-functionalized carbon nitride is shown to promote efficient charge separation and catalysis, with a photostability of at least five days. The real-world applicability of photoreforming is further verified by generating H2 and organics from a selection of non-recyclable waste – including microplastics (polyester microfibers) and food-contaminated plastic – and up-scaling the system from 2 mL to 120 mL while maintaining its efficiency for plastic conversion.