In The Travels of Marco Polo I do believe he claims that he contributed towards the construction of siege engines that made the Mongol victorious over the southern Song at Xiangyang (襄阳), however Chinese sources ^[1] credit the invention of these catapults to Islamic and Chinese engineers.

Furthermore, the battle of Xiangyang ended in 1273, however Marco Polo's second journey reached China around 1275.

Sources:

[1] - 中国攻城兵器图史 - Chinese Siege Warfare - Mechanical Artillery & Siege Weapons of Antiquity - An Illustrated History - Liang, J.

Genghis Khan & the Mongol Conquests - Turnbull, S. R.