A biomimetic system integrating Ni(II) phthalocyanine-tetrasulfonic acid with sugarcane-derived carbon quantum dots significantly enhances photoelectrochemical water oxidation. The CQDs improve light harvesting and facilitate electron transfer, resulting in higher photocurrent density, improved stability, and reduced overpotential. This sustainable strategy underscores the potential of biomass-derived nanomaterials for efficient and cost-effective solar-driven water oxidation.

Abstract

Efficient water oxidation is a crucial challenge for artificial photosynthesis and solar energy conversion. Here, we introduce a biomimetic photosynthetic system that combines Nickel(II) phthalocyanine-tetrasulfonic acid (NiPc) with carbon quantum dots (CQDs) derived from sugarcane biomass to enhance photoelectrochemical water oxidation. The CQDs effectively absorb UV and visible light, aiding electron transfer to NiPc, which significantly boosts photocurrent generation and reduces the overpotential. Electrochemical tests, including cyclic voltammetry and chronoamperometry under UV and blue light, show that the NiPc/CQD hybrid system delivers a notable increase in photocurrent density and stability compared to bare NiPc electrodes. By a membrane-free Clark-type electrode, molecular oxygen generated during photoelectrochemical water oxidation was detected. This sustainable system underscores the potential of biomass-derived CQDs as efficient, low-cost nanomaterials for solar-driven water oxidation, advancing renewable energy technologies.