CoSe₂ Subnanometer Belts with Se Vacancies and Ni Substitutions for the Efficient Electrosynthesis of High-Value-Added Nitriles Coupled with Hydrogen Generation

Abstract

The electrosynthesis of organic amines to high-value-added nitriles coupled with hydrogen generation is a highly efficient way to achieve carbon neutrality; however, the development of this method is greatly plagued by the lack of high-efficiency catalysts and an insufficient mechanistic understanding of electrochemical amine oxidation. Herein, a class of anion-vacancy and cation-substitution proof-of-concept atomically thin CoSe2 subnanometer belts (SBs) are reported to greatly boost the electrooxidation of butylamine into high-value-added butyronitrile coupled with hydrogen generation. The as-fabricated CoSe2 SBs with Se vacancies and Ni substitutions (CoSe2/Ni–SVs SBs) exhibit an ultralow onset potential of 1.3 V with up to a ∼98.5% butyronitrile Faradaic efficiency, which surpasses all the reported Co- and Ni-based catalysts. In situ electrochemical FTIR and EIS spectroscopy studies indicate that the dramatically enhanced electrooxidation performance can be attributed to the optimized adsorption behavior and accelerated dehydrogenation kinetics. Theoretical studies further reveal that Se vacancies can act as strong Lewis acid sites to effectively strengthen the adsorption of N atoms, whereas Ni substitutions are responsible for improving the dehydrogenation thermodynamics by optimizing the sequence of dehydrogenation steps. We further demonstrate that the CoSe2/Ni–SVs SBs are highly general and efficient catalysts for the electrosynthesis of propylamine, benzylamine, and cyclohexane methylamine into nitriles coupled with hydrogen generation. More importantly, a CoSe2/Ni–SVs SB-based two-electrode electrolyzer that uses amine oxidation at the anode can achieve a voltage of 1.37 V at a current density of 10 mA cm–2, which can lower the cell voltage by even 320 mV compared to that of a conventional two-electrode electrolyzer that uses the oxygen evolution reaction at the anode.

Nickel–Cobalt Selenide Electrocatalytic Electrode toward Glucose Oxidation Coupling with Alkaline Hydrogen Production

“…To understand the origin of electrocatalytic activity, we investigated the adsorption behavior of a glucose molecule on the catalyst surface. Open-circuit potential (OCP) has usually been used to reflect the variation of the adsorbates in the Helmholtz layer . When adding 100 mM glucose, the OCP of the NiCoSe x catalyst decreased by 0.52 V (Figure d), which is more than that of the NiSe x (0.38 V) and NF (0.19 V) electrode.…”

Cooperative Rh-O5/Ni(Fe) Site for Efficient Biomass Upgrading Coupled with H2 Production

“…Such anodic oxidation reaction has the additional benefit of generating value-added chemicals from inexpensive industrial by-products or renewable biomass sources . Over the past decades, tremendous efforts have been devoted to exploiting catalysts with enhanced electrocatalytic activities toward various electrooxidation reactions. , Despite these efforts, overpotentials remain too high; for example, the electrooxidation of biomass, , urea, glucose, and organic amines , mostly delivered an onset potential higher than 1.35 V, which does not represent a notable enhancement compared with the state-of-the-art electrocatalysts for the OER (∼1.45 V). − In addition, most reported catalysts function optimally only for the half–cell reaction, bifunctional catalysts capable of driving both anodic oxidation reaction and cathodic HER are rare . Developing highly efficient and durable cost-effective bifunctional electrocatalysts that can simplify the device fabrication and reduce the cost is highly desirable for the applications of electrolysis systems, but it is still a challenge.…”

CoSe2 supported single Pt site catalysts for hydrogen peroxide generation via two‐electron oxygen reduction

“…Electron paramagnetic resonance (EPR) spectroscopy was performed further to confirm the structure of Pt 1 /CoSe 2 and CoSe 2 . As shown in Figure 2E, the EPR signal at g = 2.003 is attributed to the unpaired electrons by the Se vacancies, and the vacancies concentration of Pt 1 /CoSe 2 is higher than that of CoSe 2 40–42 …”

“…As shown in Figure 2E, the EPR signal at g = 2.003 is attributed to the unpaired electrons by the Se vacancies, and the vacancies concentration of Pt 1 /CoSe 2 is higher than that of CoSe 2 . [40][41][42]…”