When Jesus fed the 5,000, the Gospel of John records that Jesus took the bread and gave thanks:
Jesus then took the loaves, and when he had given thanks, he distributed them to those who were seated. So also the fish, as much as they wanted. John 6:11 ESV
Additionally, in Mark's account of Jesus feeding the 4,000, Jesus again gives thanks, presumably in a public setting:
And he directed the crowd to sit down on the ground. And he took the seven loaves, and having given thanks, he broke them and gave them to his disciples to set before the people; and they set them before the crowd. Mark 8:6 ESV
So, Jesus does appear to pray publicly, albeit not to make a show as the Pharisees did. In this case, it appears to be private prayer prayed in public.
And when you pray, you must not be like the hypocrites. For they love to stand and pray in the synagogues and at the street corners, that they may be seen by others. Truly, I say to you, they have received their reward. Matthew 6:5 ESV
So, it does not seem reasonable to conclude that it is wrong to pray in public. Indeed, it is more reasonable to conclude that it is right to pray in both public and private settings, as long as it is with a right heart and not done for show.