Electrocatalytic nitrous oxide reduction reaction at Sn-modified Pd-Pt single crystalline electrodes in acidic media

加藤 優*; Zheng, J.*; Deng, Y.*; 斎藤 史恵*; 鵜沼 佑規*; 岡 紗雪*; 田村 和久   ; 八木 一三*

Kato, Masaru*; Zheng, J.*; Deng, Y.*; Saito, Fumie*; Unuma, Yuki*; Oka, Sayuki*; Tamura, Kazuhisa; Yagi, Ichizo*

Nitrous oxide (NO) is a greenhouse and an ozone-depleting gas. Electrocatalytic NO reduction reaction (NORR) is known to be catalyzed at noble metal electrodes such as Pd and Pt, and the surface modification of such noble metals with Sn is known to increase the NORR in acidic media. However, the role of Sn at the surface remains unclear. In this work, NORR activity was investigated for single-crystalline Pt, Pd, and Pd-Pt electrodes with the (111) or (100) plane in the presence and absence of Sn at the electrode surface in acidic media. In situ X-ray crystal truncation rod (CTR) measurements of Sn-modified Pt(111) and Pd(111) electrodes revealed the presence of metallic Sn and SnO at their surfaces. The surface Sn modification enhances the NORR activity for Pd-Pt(100) or Pd(100) electrodes but not for the Pt(111), Pd-Pt(111), or Pt(100) electrodes.