Absolutely, but cannon founding is exceptionally expensive and by the time the technology reached the Byzantines, their empire host mostly eroded away. Stephen Turnbell mentions the use of cannons in repelling the Ottomans in 1396, but that it was probable that it was the Genoese -- not the Byzantines -- who used (and owned) them.

When Mehmed II began his Siege of Constantinople, the Byzantines were offered help by the master cannon founder Orban. Roger Crowley in his book 1453 talks about how Orban felt sympathetic to the Byzantines, but that he could not work for them without the necessary funds. Unfortunately for the Byzantines, the Ottomans did have the funds, and so Orban set to building huge cannons. He would dig out giant holes and cast the bodies of the cannons in the ground. The largest was the Basicila, a 27ft cannon that could hurl a giant payload a mile -- the Basilica gave Mehmed control over the straits along the eastern side of the city. The Ottoman fleet had blockaded the Mediterranean side of Constantinople, but the Byzantines had been resupplied from the Black Sea; when the cannons were finished and hauled in to place (at outrageous expense, taking an estimated 10,000 men to move along with 500+ ox) the Byzantines were fully cut off.

So, the Byzantines did use gunpowder, but it came too late in their empire to be of use to the dwindled and depleted treasury.