Bulk defects can have both positive and negative impacts on catalysis: - Enhanced Activity: Vacancies and interstitials can create new active sites that facilitate catalytic reactions. For instance, the presence of vacancies can enhance the adsorption of reactants. - Altered Selectivity: Dislocations and other defects can change the pathway of a reaction, leading to different products. - Diffusion: Bulk defects can either hinder or promote the diffusion of reactants and products within the catalyst, affecting the overall reaction rate.