Volquez (8-2) struck out eight and gave up two hits. He has not allowed more than two earned runs in any of his 12 starts this season.
Cincinnati halted a two-game skid, but has won four of its last six.
Myers (3-7) gave up a run on one hit in 7 1/3 innings. He struck out eight, but walked six.
Philadelphia had won three in a row and eight out of nine.
Myers issued a one-out walk to Brandon Phillips in the seventh and Phillips stole second. With two away, Votto doubled to center on an 0-2 pitch to end the no-hit bid and put the Reds in front.
Votto doubled again in the ninth, again driving in Phillips, who had singled and stolen his second base of the game.