For Into Darkness he appears to have been focused on scenic design, where he worked on the look for Qo'noS, Earth, and the Nibiru volcano. I've picked out a few of my favourites from his portfolio here, including a Blade Runner-esque take on Qo'noS, and a busy future Earth full of organic forms. You can see much more on Schroeder's site.
For the first nuTrek film, Schroeder's work was focused on the design of Spock's ship, the Jellyfish. Continue after the jump for a few of my favourite concepts for that design, or again, make your way to Schroeder's site to see a lot more.
For more on the production design of the nuTrek films, there is an excellent book covering the first film, Star Trek: The Art of the Film. Unfortunately there has been no equivalent for Into Darkness, but you can find links to my coverage of lots of other concept art and other behind-the-scenes stuff on my Into Darkness guide page.