Electrocatalytic activity and volatile product selectivity for nitrate reduction at tin-modified Pt(100), Pd(100) and Pd–Pt(100) single crystal electrodes in acidic media. (1st December 2021) - Kato, Masaru
Highlights: Sn/Pt(100), Sn/Pd(100) and Sn/Pd–Pt(100) were prepared for the nitrate reduction. Gasous products for the electrochemical NO3 RR were analyzed using OLEMS. Sn/Pd(100) and Sn/Pd-Pt(100) produced N2 but not Sn/Pt(100). Abstract: We prepared Sn-modified Pt(100), Pd(100) and Pd–Pt(100) single crystal electrodes and investigated the nitrate reduction reaction (NO3 RR) activity and the product selectivity for them using online electrochemical mass spectroscopy (OLEMS), also known as differential electrochemical mass spectroscopy (DEMS). OLEMS measurements allowed us to quantify volatile products of N2, N2 O and NO and confirm the production of N2 at Sn/Pd(100) but not at Sn/Pt(100). Pd-doping to Pt(100) with a 3 atomic % increased the product selectivity for the NO3 RR to N2 . These results indicate that the presence of Pd in the (100) surface is the key to produce N2, which seems to be related to the hydrogen adsorption energy to the metal surface. The suppression of hydrogenation of intermediate species at the electrode surface could lead to the production of N2 . This work will guide us to understand N2 production mechanism for the NO3 RR and develop highly selective electrocatalysts for denitrification. Graphical abstract: Image, graphical abstract