Embodiments described herein generally relate to hydrogenation catalysts, syntheses of hydrogenation catalysts, and apparatus and methods for hydrogenation. Methods for forming a hydrogenation catalyst may include mixing a silica generating precursor with a copper precursor and adding an ammonium salt to an end pH of between about 5 to about 9. Methods for hydrogenating an oxalate may include forming a reaction mixture by flowing a hydrogenation catalyst to a reactor, flowing a hydrogen source to the reactor, and flowing an oxalate to the reactor, wherein the hydrogenation catalyst has a particle size between about 10 nm to about 40 nm. Methods may further include reacting the oxalate to form ethylene glycol.