Molecular Engineering to Tune the Ligand Environment of Atomically Dispersed Nickel for Efficient Alcohol Electrochemical Oxidation

Abstract

Atomically dispersed metals maximize the number of catalytic sites and enhance their activity. However, their challenging synthesis and characterization strongly complicates their optimization. Here, the aim is to demonstrate that tuning the electronic environment of atomically dispersed metal catalysts through the modification of their edge coordination is an effective strategy to maximize their performance. This article focuses on optimizing nickel-based electrocatalysts toward alcohol electrooxidation in alkaline solution. A new organic framework with atomically dispersed nickel is first developed. The coordination environment of nickel within this framework is modified through the addition of carbonyl (CO) groups. The authors then demonstrate that such nickel-based organic frameworks, combined with carbon nanotubes, exhibit outstanding catalytic activity and durability toward the oxidation of methanol (CH 3 OH), ethanol (CH 3 CH 2 OH), and benzyl alcohol (C 6 H 5 CH 2 OH); the smaller molecule exhibits higher catalytic performance. These outstanding electrocatalytic activities for alcohol electrooxidation are attributed to the presence of the carbonyl group in the ligand chemical environment, which enhances the adsorption for alcohol, as revealed by density functional theory calculations. The work not only introduces a new atomically dispersed Ni-based catalyst, but also demonstrates a new strategy for designing and engineering high-performance catalysts through the tuning of their chemical environment.

Insights into the activity of nickel boride/nickel heterostructures for efficient methanol electrooxidation

“…During the reactions, nucleophilic groups containing active hydrogen atoms in these organic substrates undergo dehydrogenation processes to form oxygen-rich products. Nickel-based electrocatalysts have been demonstrated as potential candidates for NOR 21 , 22 . However, much ambiguity is present regarding the mechanism of NOR.…”

Co–Ni Layered Double Hydroxide for the Electrocatalytic Oxidation of Organic Molecules: An Approach to Lowering the Overall Cell Voltage for the Water Splitting Process

“…The products formed were analyzed by using 1 H NMR spectroscopy. The proton NMR spectrum of the BAOR in Figure S21 has peaks in the range of 7.0–8.0 ppm corresponding to the phenyl ring, whereas a peak for carboxylic group protons is absent since the mixture is in alkaline medium and thus favors benzoate formation . The proton NMR spectrum of the EOR mixture in Figure S22 depicts the peak between 1.5 and 2.0 ppm for acetate .…”

“…The proton NMR spectrum of the BAOR in Figure S21 has peaks in the range of 7.0−8.0 ppm corresponding to the phenyl ring, whereas a peak for carboxylic group protons is absent since the mixture is in alkaline medium and thus favors benzoate formation. 68 The proton NMR spectrum of the EOR mixture in Figure S22 depicts the peak between 1.5 and 2.0 ppm for acetate. 68 Similarly, the proton NMR spectrum of the GOR mixture showcases peaks at around 8.3 ppm, confirming the product as formate (Figure S23).…”

“…68 The proton NMR spectrum of the EOR mixture in Figure S22 depicts the peak between 1.5 and 2.0 ppm for acetate. 68 Similarly, the proton NMR spectrum of the GOR mixture showcases peaks at around 8.3 ppm, confirming the product as formate (Figure S23). 17 The electrooxidation of benzyl alcohol, ethanol, and glycerol produces benzoate, acetate, and formate, respectively, which are considered as value-added chemicals in industries.…”

Nitrogen-doped nickel-molybdenum oxide as a highly efficient electrocatalyst for benzyl alcohol oxidation

“…3d). A smaller semicircle of BOR indicates a lower charge transfer re-sistance in the fitting of Nyquist plots, 34 revealing an extremely faster charge transfer rate of BOR compared to OER at the anode. The influence of Mo concentration in the raw material on the electrocatalytic activity was also investigated.…”