Alternating Current Electrolysis for Individual Synthesis of Methanol and Ethane from Methane in a Thermo-electrochemical Cell

Abstract

The individual synthesis of methanol and ethane from methane was investigated using a thermo-electrochemical cell in gas flow mode over the temperature range of 150–200 °C. Methane was directly oxidized at an anode consisting of sub-10 nm Pt and Fe particles. In the electrolysis of humidified methane, methanol was produced through the formation of active oxygen intermediates from water vapor. In the electrolysis of unhumidified methane, ethane was produced via the dissociation of C–H bonds, followed by dimerization of the resultant •CH3 radicals. However, the formation rates for the target products decreased with time during electrolysis because of overoxidation of the anode by the direct-current (DC) voltage. The alternating current (AC) electrolysis of methane avoided this problem. Under optimized AC polarization conditions at a square waveform voltage of ±2.5 V with a pulse time of 5 s, this cell generated methanol and ethane at rates of 5.1 × 10–5 mol m–2 s–1 (92 mmol gcat –1 h–1) and 3.8 × 10–5 mol m–2 s–1 (69 mmol gcat –1 h–1), respectively, without a substantial loss of activity during continuous electrolysis.

Biocatalysts for biomethanol production: Advancements and future prospects

“…Further efforts were made on the economic perspective on methanol production and it was found nearly $1040.2 and $1669.6/mt tonnes methanol for PV-grid and also PV-battery respectively. Further study was shown on environmental perspectives of the process of CO2-eq emission from the whole process of methanol synthesis and then it was shown two different values (like 0.244 kg-CO2-eq/MJ-methanol) for PV-grid and PV-battery system respectively [28,29] .…”

“…In the electrolysis of humidified methane, methanol was produced through the formation of active oxygen intermediates from water vapor [28] Novel methanol production process developed by integrating CO2…”

Programmed alternating current optimization of Cu-catalyzed C-H bond transformations

“…ac.uk/data_request/cif under identifier 2189825. Experimental procedures, optimization data, 1 H NMR spectra, 13 C NMR spectra, 19 F NMR spectra, EPR spectra, ESI-MS spectrometry data, AAS data, and other characterization details are available in the supplementary materials. License information: Copyright © 2024 the authors, some rights reserved; exclusive licensee American Association for the Advancement of Science.…”

“…Nonetheless, most electrolytic technologies for chemical manufacturing remain driven by DC electricity (2)(3)(4)(5)(6)(7)(8), as exemplified by water-splitting and chlor-alkali processes (9,10). Compared with DC, which can only modulate current (I ) or voltage (U), AC electrosynthesis, characterized by polarity reversal, offers an array of extra-adjustable parameters to fine-tune the reaction process, including frequency (f) (11)(12)(13), duty ratio (D; the ratio of positive half-period to the whole period) (14), and waveform function (Fig. 1A) (15).…”

Physico-chemical principles of AC electrosynthesis

“…The latter has the advantage of introducing additional controllable parameters such as oscillation frequency and waveform shape, creating more opportunities for reaction control [15][16][17][18][19][20][21]. In particular, this has been useful in minimising loss of electrocatalysts [22][23][24][25][26], achieving paired electrosynthesis [24,[27][28][29][30][31], and improving chemical selectivity [26,28,[32][33][34][35][36][37][38][39][40][41][42][43]. These benefits are also transferrable to the manufacturing industry -recently, Hioki et al used AC to upgrade biomass-derived carboxylic acids into valuable polymers [40], setting yet another milestone in green engineering.…”