Doping can affect catalysts in several ways: 1. Electronic Modification: Doping can change the electronic properties of the host material, thereby affecting the adsorption and activation of reactants. 2. Structural Modification: Doping can introduce defects or alter the crystal structure, creating new active sites. 3. Thermal Stability: Doping can enhance the thermal stability of catalysts, making them more resistant to sintering and deactivation.