Efficient pollutant degradation via non-radical dominated pathway by self-regenerative Ru(bpy)32+/peroxydisulfate under visible light

Advanced oxidation processes based on activation of peroxydisulfate (PDS) typically require energy or chemical input, for which ultraviolet light and metal catalyst are commonly adopted. However, the sluggish reaction kinetics due to insufficient catalyst redox cycling and limited solar energy utilization remain a key challenge to be addressed. Here, we report a visible light-driven Ru(bpy)(3)(2+)/PDS system that allows for highly-efficient and sustained pollutant degradation, at efficiencies far exceeding the existing PDS-based reaction systems. The degradation rate of Rhodamine B (RhB) was 40-fold higher than that achievable by the state-of-the-art Fe2+/PDS system. The Ru(bpy)(3)(3+) reduction was closely coupled with the pollutant oxidation, enabling an efficient Ru (bpy)(3)(2+)/Ru(bpy)(3)(3+) cycling and RhB degradation via non-radical dominated pathway in the Ru(bpy)(3)(2+)/PDS/vis system. The high activity of the catalyst towards multiple antibiotics and its high stability and robustness over a wide pH range and in the presence of various environmental anions were also demonstrated. This work provides solid evidence to support a direct oxidation of pollutant by high-valent metal complex, and may inspire new development of solar-responsive catalysts for efficient, sustainable advanced oxidation processes.