| 초록 |
Direct synthesis of hydrogen peroxide (H2O2) has been studied extensively over the past decades, however, the efficiency of the catalysts remains unsatisfactory. In order to achieve high catalytic selectivity towards H2O2 from an H2/O2 mixture, H-H bonds should be dissociated while O-O bonds should be kept unbroken in the course of the catalytic reaction. However, a major dilemma in the catalyst design is that the metal catalysts that dissociate H-H bonds even prefer O-O bonds dissociation thermodynamically. Here we report that selective dissociation of H2 over O2 was realized by depositing H2-selective carbon diffusion layers on the top of a Pt catalyst. Because O2 cannot access to the carbon-coated Pt surface, O2 hydrogenation occurs at the carbon surface via spilt-over hydrogen rather than at the Pt surface where O-O dissociation is preferably. Such catalyst using the hydrogen spillover phenomena leads to the great suppression of O-O dissociation, which allows highly selective synthesis of H2O2. Notably, nitrogen doping on the carbon diffusion layer could significantly increase the selectivity towards H2O2 due to the stabilization of the reaction intermediate hydroperoxy radical on the carbon surface. |
