High-Grade Biofuel Synthesis from Paired Electrohydrogenation and Electrooxidation of Furfural Using Symmetric Ru/Reduced Graphene Oxide Electrodes

Abstract

Electrochemical hydrogenation is a challenging technoeconomic process for sustainable liquid fuel production from biomass-derived compounds. In general, half-cell hydrogenation is paired with water oxidation to generate the low economic value of O 2 at the anode. Herein, a new strategy for the rational design of Ru/reduced graphene oxide (Ru/RGO) nanocomposites through a cost-effective and straightforward microwave irradiation technique is reported for the first time. The Ru nanoparticles with an average size of 3.5 nm are well anchored into the RGO frameworks with attractive nanostructures to enhance the furfural’s paired electrohydrogenation (ECH) and electrooxidation (ECO) process to achieve high-grade biofuel. Furfural is used as a reactant with the paired electrolyzer to produce furfuryl alcohol and 2-methylfuran at the cathode side. Simultaneously, 2-furic acid and 5-hydroxyfuroic acid along with plenty of H + and e – are generated at the anode side. Most impressively, the paired electrolyzer induces an extraordinary ECH and ECO of furfural, with the desired production of 2-methylfuran (yield = 91% and faradic efficiency (FE) of 95%) at X FF = 97%, outperforming the ECH half-cell reaction. The mechanisms of the half-cell reaction and paired cell reaction are discussed. Exquisite control of the reaction parameters, optimized strategies, and the yield of individual products are demonstrated. These results show that the Ru/RuO nanocomposite is a potential candidate for biofuel production in industrial sectors.

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

“…In other words, anodic OER is main efficiency bottleneck for these processes. In addition to accelerate the OER, electrooxidation reactions of organics such as methanol 13 , urea 14 , 5-hydroxymethylfurfural 15 , 16 , furfural 17 and glucose 18 have been proposed to replace sluggish OER. These organic electrooxidation reactions possess lower onset potentials than OER, thereby reducing the cost of electrolysis.…”

“…These organic electrooxidation reactions possess lower onset potentials than OER, thereby reducing the cost of electrolysis. Meanwhile, value-added products can also be obtained at the anode 17 ; or the purpose of degrading wastewater can be achieved 19 .…”

Recent progress of Cu-based electrocatalysts for upgrading biomass-derived furanic compounds

“…The oxidative conversion of furans provides important intermediates for pharmaceuticals, fragrances, dyestuffs, and other fields. 7,40 As an alternative reaction to OER at anodes, ECO provides not only a green and economical way for furans oxidation 41 but also a feasible way to cut down the cell voltage for water electrolysis when it is paired with cathodic HER. [42][43][44] Similar to ECH, the ECO includes inner and outer sphere pathways.…”

Unraveling Electroreductive Mechanisms of Biomass-Derived Aldehydes via Tailoring Interfacial Environments

“…In the past few years, research efforts have been dedicated to exploring electrocatalysts and/or processes to improve the selectivity toward a target product and increase its energy efficiency. − However, mechanistic understanding of electrochemistry in aldehyde transformation, through ECH of furfural as a model reaction, remains insufficient. Our previous study has distinguished the ECH pathway toward alcohol/alkyl (i.e., FA/MF) and the direct outer-sphere pathway toward dimeric (i.e., hydrofuroin) products on Cu electrodes and highlighted the vital role of adsorption of hydrogen in their production rates and selectivity.…”