Graphitic Carbon Nitride–Nickel Catalyst: From Material Characterization to Efficient Ethanol Electrooxidation

Abstract

Graphitic carbon nitride (gCN­(H)) is a semiconductor with high mechanical and thermal stability which provides good dispersion of metal particles. As it is resistant to corrosion, it constitutes an alternative to carbon black as a catalyst support in polymer electrolyte membrane fuel cells (PEMFCs), e.g., in alcohol oxidation reactions. In this research work, gCN (H)-supported catalyst has been characterized by spectroscopic (UV–vis, IR, Raman) and microscopy techniques (SEM, TEM, AFM) in order to gain deeper understanding of the relationship between material properties and electrochemical activity. Ni-doped graphitic carbon nitride (Ni/gCN­(H)) was tested in electrooxidation of ethanol demonstrating comparatively high peak current density and interesting photocatalytic properties. The obtained results suggest that the improvement of the activity and selectivity of Ni-modified gCN­(H) can be related to the chemical and electronic material modification, while the sample morphology and topology is preserved. Metal–support interactions account for the high photocatalytic activity, superior to that of the Pt counterpart.

The Hallmarks of Copper Single Atom Catalysts in Direct Alcohol Fuel Cells and Electrochemical CO2 Fixation

“…The electrochemical CO 2 reduction reaction (CO 2 RR) to C 1 ‐C 2 hydrocarbon (HC) fuels and chemicals using surplus or renewable electricity, as well as the electrochemical conversion of small organic molecules (SOM) to sustainable energy, can be seen as a closed cycle strategy with maximized energy harvesting efficiency in a “carbon‐neutral” or even a “carbon‐negative” manner. [ 1–6 ] Meanwhile, CO 2 RR can also reduce the global carbon footprint and remediate global climate change. Among SOM, bio‐derived C 1 ‐C 2 alcohols (methanol, ethanol) and simple ethers (DME – dimethyl ether and DEE – diethyl ether) receive particular attention because they present several advantages comparing to hydrogen, that is, fuel storage safety.…”

“…The development of advanced fuel cells, based on bio‐derived fuels and rationally designed catalytic nanostructured electrodes with a lowered amount of platinum group metals (PTG) and proven stability offers new opportunities for the applications of future sustainable energy. [ 1,2,12,13 ] For highly efficient energy conversion, it is crucial to progress the electrochemical devices, electrolytes, and electrochemical reaction procedures as well as tailor electrocatalysts’ activity, considering both CO 2 RR and SOM electro‐oxidation selectivities, and overcome kinetic limitations. Although extensively studied electro‐oxidation reactions of methanol (MOR) was found to have more efficiency in alkaline than acidic media, the slow kinetic of MOR on the anode are among the main problems in the application of direct alcohol fuel cells (DAFC).…”

“…Although extensively studied electro‐oxidation reactions of methanol (MOR) was found to have more efficiency in alkaline than acidic media, the slow kinetic of MOR on the anode are among the main problems in the application of direct alcohol fuel cells (DAFC). [ 1,2 ] Similarly, the critical CO 2 RR challenges concerns the electrocatalyst's and electrolyzer's designs, namely i) process selectivity enhancement, especially in a in single‐product Faradaic efficiency (FE) enhancement, [ 14 ] ii) energy efficiency improvement while reducing the over‐potentials, [ 15,16 ] iii) system and operating cost reduction, by reaction protocols and rational catalysts design. [ 14–18 ]…”

Investigations of Carbon Nitride-Supported Mn3O4 Oxide Nanoparticles for ORR

“…A thorough review of their applications for water splitting was presented by Mishra et al [7]. Other applications include the use of carbon nitride as a support for catalysts, such as nickel NPs for ethanol electro-oxidation [8], gold NPs for three-component coupling reactions [9], Ag 2 MoO 4 NPs for photocatalytic pollutant degradation [10], and iron carbide for the oxygen reduction and evolution reactions [11]. One of the key elements of their effectiveness is the high abundance of N-functional groups, potentially acting as anchoring sites for metal species thereby enabling tuning of physico-chemical properties.…”

Photoelectrochemical Studies on Metal-Doped Graphitic Carbon Nitride Nanostructures under Visible-Light Illumination

“…Takanabe et al [24] synthesized a MgPc/mpg-C 3 N 4 photocatalyst to expand light absorption for the evolution of hydrogen. Recently, a Ni/g-C 3 N 4 catalyst was designed for efficient ethanol electro-oxidation [25]. Gong et al [26] developed NiO and Ni co-doped g-C 3 N 4 for octylphenol sensing applications.…”