Highly performed platinum nanosheets synthesized under in situ reaction conditions for hydrogen generation

Surface properties of a catalyst, especially exposed crystal facets and coordination states, directly affect the catalyst's performance. Herein, we illustrate how reaction conditions direct the fabrication of a wellbehaved catalyst with desired structures in the case of hydrogen evolution reaction (HER). Stable adsorbed PtClx ions on CNTs are in situ electrochemically reduced into a unique Pt nanosheet structure enclosed by high-index (311) and low-index (200) and (111) facets during HER process. Experimental results and density functional theory (DFT) calculation disclose the function mechanism between these unique structures and reactants. The adsorbed H2O and reactive species act as capping agents protecting the (311) facet where the dissociation of water molecule is promoted, and the produced H * intermediates favorably combine and release on the nearby low-index Pt sites. The joint collaborations of these active sites afford Pt nanosheets comparable activity to 20 wt% Pt/C and a 12.7-fold over mass activity. These findings provide novel insight into the synthesis of heterogeneous catalysts with high specificity. (c) 2020 Published by Elsevier B.V. and Science Press on behalf of Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences