Synergistic cocatalytic effect of MoO3 and creatinine on Cu–Fenton reactions for efficient decomposition of H2O2

The key scientific problems with conventional Fenton reactions are the acidic pH dependence and low ROS production due to inefficient decomposition of H2O2. Although Cu–Fenton reactions can break the pH limitation, there is still an urgent need to improve the overall reaction efficiency, and thus broaden its applicability. Herein, we describe a synergistic strategy by introducing MoO3 cocatalyst and creatinine (Cr) assistant to enhance the efficiency of Cu–Fenton reactions at near-neutral pH. In this strategy, Cu2+ interacts with Cr to form a complex (CuCr2), which is then mainly linked to MoO3 via the Cu2+ binding site (CuCr2/MoO3). Experimental and theoretical calculation results manifest that the CuCr2/MoO3 exhibits an excellent cocatalytic activity, which significantly facilitates the rate-limiting step of Cu–Fenton reactions, and enables the efficient decomposition of H2O2 for the generation of three reactive oxygen species (ROS, •OH, 1O2, •O2−). More significantly, this cocatalytic system with high oxidation activity can be applied for the detection of Cu2+ and ROS-based chemodynamic therapy (CDT), as well as sterilization of Escherichia coli. This study represents a new breakthrough in improving the efficiency of Fenton-based reactions with a facile and promising strategy, and drives great progress in practicality.