exothermic catalyst

例句：

1. 1.The engine is exothermic and needs to be cooled down before it can operate properly.
   这个发动机是放热的，需要在它能够正常工作之前冷却。
2. 2. The reaction is exothermic, meaning it releases heat.
   这个反应是放热的，意味着它会释放热量。
3. 3. The process of photosynthesis is exothermic, which means it generates energy from sunlight.
   光合作用的过程是放热的，这意味着它是从阳光中产生能量的。