Tristan Jarry made 27 saves for Pittsburgh (31-14-5), which lost for the second time in eight games (6-2-0).
Sidney Crosby, who had a four-game point streak (three goals, five assists) since returning to the Pittsburgh lineup Jan. 14 after missing 28 games following core muscle surgery, had two shots on goal.
The Penguins' 19 shots were the second fewest they've had in a game this season (16 in a 4-3 win at the Vegas Golden Knights on Jan. 7).
"For me, there was a lack of execution, lack of attention to detail, no sense of urgency, no cooperative play," coach Mike Sullivan said. "Can't play that way in this league and expect to win.
"There was lots we could have done better. Tonight, we were easy to play against. ... We didn't chip bodies, finish checks, we didn't make great decisions with the puck, we didn't execute when we had it. There was nothing positive I can draw on from this game. It's disappointing."
Voracek gave the Flyers a 1-0 lead at 5:26 of the second period when he took a pass from Sean Couturier, cut through the crease, and scored with a backhand.
Van Riemsdyk tipped in a Konecny pass with 1:20 left in the second to make it 2-0.
Braun scored an empty-net goal with one minute remaining for the 3-0 final.
It was the Flyers' second shutout of the season; Carter Hart made 25 saves in a 4-0 win against the New Jersey Devils on Oct. 9. The 19 shots-against were the fewest they allowed since the Buffalo Sabres had 17 on Dec. 19 in a 6-1 Philadelphia win.
"I think in these sorts of games you've got to be careful not to get too far ahead of yourself," van Riemsdyk said. "I thought it was a pretty mature game from us knowing that situation. You have this nice break coming up, you want to feel good about where your game is at going into it as a team, and I thought we did a lot of really good things out there, handled the business we needed to do, and now we can enjoy some time off."