Underpotential Deposition of 3D Transition Metals: Versatile Electrosynthesis of Single‐Atom Catalysts on Oxidized Carbon Supports

Abstract

Use of single‐atom catalysts (SACs) has become a popular strategy for tuning activity and selectivity towards specific pathways. However, conventional SAC synthesis methods require high temperatures and pressures, complicated procedures, and expensive equipment. Recently, underpotential deposition (UPD) has been investigated as a promising alternative, yielding high‐loading SAC electrodes under ambient conditions and within minutes. Yet only few studies have employed UPD to synthesize SACs, and all have been limited to UPD of Cu. In this work, we report a flexible UPD approach for synthesis of mono‐ and bi‐metallic Cu, Fe, Co, and Ni SACs directly on oxidized, commercially available carbon electrodes. We investigate the UPD mechanism using in‐situ x‐ray absorption spectroscopy and, finally, assess the catalytic performance of a UPD‐synthesized Co SAC for electrochemical nitrate reduction to ammonia. Our findings expand upon the usefulness and versatility of UPD for SAC synthesis, with hopes of enabling future research towards realization of fast, reliable, and fully electrified SAC synthesis processes.This article is protected by copyright. All rights reserved

Effects of Ionic Interferents on Electrocatalytic Nitrate Reduction: Mechanistic Insight

“…For example, one of the primary design goals can be the enhancement of adsorption affinity for NO 3 – over ionic impurities in IHP. These features could be achieved by developing materials with tandem catalytic functions, abundant oxygen vacancies or defects, or a positively charged surface via surface coatings. ,, Reconstruction of the electronic structure during electroreduction can also tailor the catalyst surface to enhance the adsorption of intermediates through the interaction with co-existing ions. ,, Developing electrodes with optimal cation-induced electric fields for the stabilization of intermediates and the dissociation of water molecules within the EDL would be of great interest. , Furthermore, given the improved selectivity for NH 3 , albeit often accompanied by an undesired increase in the HER activity, electrodes characterized by an optimal HBE are deemed ideal. , Adjusting catalytic materials to limit HER by minimizing exposure of reactive H* adsorption sites is feasible. Achieving this may involve diminishing the prevalence of surface-terminated OH* and O* groups, which function as active sites for the HER through the facilitation of hydrogen bond formation .…”

“…90,332,333 Reconstruction of the electronic structure during electroreduction can also tailor the catalyst surface to enhance the adsorption of intermediates through the interaction with co-existing ions. 121,334,335 Developing electrodes with optimal cation-induced electric fields for the stabilization of intermediates and the dissociation of water molecules within the EDL would be of great interest. 270,281 Furthermore, given the improved selectivity for NH 3 , albeit often accompanied by an undesired increase in the HER activity, electrodes characterized by an optimal HBE are deemed ideal.…”

Controlled Growth of PtCux Quantum Dots on Graphdiyne for Efficient Ammonia Production

“…The PtCu x /GDY catalyst demonstrates a remarkable FE of 96.5 ± 5.1% and Y NH3 value of 345.3 ± 38.9 μmol NH3 cm –2 h –1 at −0.5 V versus RHE, surpassing that of PtCu x /CC, Pt/GDY, Cu/GDY and many reported electrocatalysts (Figures c,d, S21, and S22). − ,− The PtCu x /GDY catalyst exhibited superior catalytic performance at −0.5 V (vs RHE) compared to all other control groups (Figure e). Control experiments were performed to confirm that the NH 3 produced was indeed derived from the NtRR.…”