Catalytic reactions possess four fundamental characteristics, which can be derived from their definitions and are crucial for understanding the function of catalysts.

1. Catalysts can only accelerate reactions that are thermodynamically feasible. When developing new catalysts for chemical reactions, it is necessary to first conduct a thermodynamic analysis of the reaction to determine whether it is thermodynamically viable.

2. Catalysts can only accelerate the reaction towards equilibrium, but cannot change the equilibrium position (equilibrium constant) of the reaction.

3. Catalysts exhibit selectivity towards reactions. When a reaction has multiple possible directions, catalysts accelerate one of them, thereby promoting both the reaction rate and selectivity.

4. The lifespan of the catalyst. Catalysts can alter the rate of chemical reactions without themselves participating in the reaction, and ideally, they should remain unchanged by the reaction. However, in actual reaction processes, catalysts can undergo some irreversible physicochemical changes due to long-term exposure to heat and chemical reactions.

Based on the analysis of the definition and characteristics of catalysts, there are three important catalyst indicators: activity, selectivity, and stability.