Enhanced Photostability and Photoactivity of Ruthenium Polypyridyl-Based Photocatalysts by Covalently Anchoring Onto Reduced Graphene Oxide

Abstract

Recentstudies toward finding more efficient ruthenium metalloligands for photocatalysis applications have shown that the derivatives of the linear [Ru(dqp) 2 ] 2+ (dqp: 2,6-di(quinolin-8-yl)-pyridine) complexes hold significant promise due to their extended emission lifetime in the μs time scale while retaining comparable redox potential, extinction coefficients, and absorption profile in the visible region to [Ru(bpy) 3 ] 2+ (bpy: 2,2′-bipyridine) and [Ru(tpy) 2 ] 2+ (tpy: 2,2′:6′,2″-terpyridine) complexes. Nevertheless, its photostability in aqueous solution needs to be improved for its widespread use in photocatalysis. Carbon-based supports have arisen as potential solutions for improving photostability and photocatalytic activity, yet their effect greatly depends on the interaction of the metal complex with the support. Herein, we present a strategy for obtaining Ru−polypyridyl complexes covalently linked to aminated reduced graphene oxide (rGO) to generate novel materials with long-term photostability and increased photoactivity. Specifically, the hybrid Ru(dqp)@rGO system has shown excellent photostable behavior during 24 h of continual irradiation, with an enhancement of 10 and 15% of photocatalytic dye degradation in comparison with [Ru(dqp) 2 ] 2+ and Ru(tpy)@rGO, respectively, as well as remarkable recyclability. The presented strategy corroborates the potential of [Ru(dqp) 2 ] 2+ as an interesting photoactive molecule to produce more advantageous light-active materials by covalent attachment onto carbon-based supports.