Selective increase in CO 2 electroreduction activity at grain-boundary surface terminations

Going with the grain boundaries Bulk defects in a metal, such as grain boundaries, can create regions of increased strain at its surface that could affect its catalytic activity. Mariano et al. studied the electroreduction of CO 2 to CO on polycrystalline gold films, a reaction that competes with H 2 evolution. By annealing the films to create larger grains, they could change the types and distribution of grain boundaries at the surface. Scanning electrochemical cell microscopy revealed that the dislocation density correlated with CO 2 electroreduction activity, but such defects had no effect on H 2 evolution. Science , this issue p. 1187