(Phys.org) —When it comes to making catalysts that quickly snap chemical bonds and free the stored energy, researchers often focus on the active site. However, small changes far from the active site can also have a large impact. Taking a cue from enzymes, researchers at Pacific Northwest National Laboratory (PNNL) placed the amino acid arginine at the periphery of a hydrogen-splitting catalyst that cleaves hydrogen into protons and electrons. The arginine’s carboxylic acid groups accelerated proton transfer and made the catalyst more energy efficient. At the same time, the arginine guanidinium groups interacted with each other to increase the rate of hydrogen binding and activation. With the appended arginine and at 133 atm hydrogen, this nature-inspired catalyst can split 144,000 molecules of hydrogen in a single second.