Dye-sensitized solar cells (DSSCs) have attracted widespread attention in recent years as potential cost-effective alternatives to traditional solar cells.Within DSSCs, the counter electrode (CE) is crucial for collecting electrons from the external circuit to reduce I3-ions in the electrolyte.Careful design of the CEs can improve the catalytic activity and chemical stability associated with the liquid redox electrolyte used in most cells.Mesoporous-graphitic-carbon-supported HfO2 nanohybrids were synthesized by using a soft-template route.A systematic investigation of the catalytic properties, stability, and catalytic mechanism, including fiust-principle density functional theory (DFT) calculations and ab-initio Car-Parrinello molecular dynamics (CPMD) simulations, were performed for HfO2-based hybrid CEs in DSSCs.The HfO2-based hybrids as a CE in DSSCs showed a surprisingly high efficiency for the I3-/I-and T2/T-redox couples, greater than the Pt electrode.