2 sentences

1. 这种催化剂在化学反应中起作用。

   zhè zhǒng cuī​huà​jì zài huà​xué fǎn​yìng zhōng qǐ zuò​yòng.

   This catalyst plays a role in the chemical reaction.

   Source: Dong Chinese Dictionary

2. 这种化学物质在实验中起到了催化剂的作用，加速了反应。

   zhè zhǒng huà​xué wù​zhì zài shí​yàn zhōng qǐ​dào le cuī​huà​jì de zuò​yòng, jiā​sù le fǎn​yìng.

   This chemical acted as a catalyst in the experiment, accelerating the reaction.

   Source: Dong Chinese Dictionary