Alloying effect-induced electron polarization drives nitrate reduction to ammonia

Abstract

Electrocatalytic conversion of nitrate (NO3-) to ammonia (NH3) holds significant potential in the control of nitrogen oxide (NOx) from stationary sources. However, previous studies on reaction intermediates remain unclear. Here we report that Pd/Cu2O hybrids with mesoporous hollow sphere structure show high selectivity (96.70%) and Faradaic efficiency (94.32%) for NH3 synthesis from NO3-. Detailed characterizations demonstrate that (1) Pd enables electrons transfer (Pd 3d → Cu 3d) and makes the polarization of Cu 3d orbitals by forming partial PdCu alloys, which makes Pd electron-deficiency but offers empty orbits to adsorb NO3-; (2) electron-rich Cu are more conducive to the occurrence of NO3- reduction. The mutual confirmation of online differential electrochemical mass spectrometry and density functional theory calculations demonstrates that PdCu alloys block the generation of *NOH intermediate and facilitate the formation of *N, finally leading to a higher catalytic performance.

Theoretical study of catalyst design for condensed phase reaction

“…In theoretical study, two solvation methods, the explicit method [72][73][74][75][76][77][78] and the implicit method [79][80][81][82][83] are widely used to implement the condensed phase in the unit cell of the computational environment. The explicit solvation method directly incorporates every solvent molecule in the condensed phase in the simulation box.…”