Photosynthesis is the process by which nature harvests sunlight and uses the solar energy to synthesize carbohydrates from carbon dioxide and water.
Artificial versions of photosynthesis are being explored for the clean, green and sustainable production of chemical products now made from petroleum, primarily fuels and plastics.
Cadmium sulfide is a well-studied semiconductor with a band structure and that is well-suited for photosynthesis. As both an "electrograph" (meaning it can undergo direct electron transfers from an electrode), and an "acetogen" (meaning it can direct nearly 90-percent of its photosynthetic products towards acetic acid), M. thermoacetica serves as the ideal model organism for demonstrating the capabilities of this hybrid artificial photosynthesis system.
By inducing the self-photosensitization of M. thermoacetica with cadmium sulfide nanoparticles, authors enabled the photosynthesis of acetic acid from carbon dioxide over several days of light-dark cycles at relatively high quantum yields, demonstrating a self-replicating route toward solar-to-chemical carbon dioxide reduction.
"We've demonstrated the first self-photosensitization of a non-photosynthetic bacterium, M. thermoacetica, with cadmium sulfide nanoparticles to produce acetic acid from carbon dioxide at efficiencies and yield that are comparable to or may even exceed the capabilities of natural photosynthesis," says the author.