Recent Developments of Methanol Electrooxidation Using Nickel‐based Nanocatalysts

Abstract

Studies of methanol electrooxidation reactions have achieved considerable advancements in the recent years for their encouraging contributions in the exciting fields of energy conversion and storage, organic syntheses, wastewater treatment, sensing, medicinal and environmental analyses, and many others thriving fields of modern technology. Accordingly, the fabrication of less expensive, efficient and decent quality electrocatalysts with high material stability, faster electro‐oxidation kinetics, as well as less carbonation and decent corrosion inhibition activities are highly urged. Consequently, scientists around the globe are in continuous search for alternative economical smart anode‐nanocatalysts for methanol oxidations with superior electrochemical performances. In the recent years, various inexpensive and readily‐available nanocatalysts of non‐noble metals like Ni, Co, Cu, etc., in reference to electrooxidation of organic molecules have been reported. The present work highlights the recent progress accomplished by rapidly flourishing nickel‐based electrocatalysts for electrooxidation of methanol. The discussion comprehensively includes the basic mechanistic understandings and fundamentals for achieving high efficacy of methanol electrooxidation with nickel‐based electrocatalysts. Also, the current challenges faced in this emerging area have been outlined to achieve superior, productive, and commercially viable catalysts for methanol electrooxidation in the near future.

Hybrid water electrolysis with integrated and cascading reactions using two-dimensional electrocatalysts

“…The anodic electrooxidation reaction of monohydric alcohols, such as methanol and ethanol, has been extensively studied as a platform for hybrid water electrocatalysis for the HER. 93 Taking the methanol/ethanol oxidation reaction (MOR/EOR) as the typical example, the electrolyte's pH and the type and structure of the electrocatalyst greatly affected the reaction pathway and reactant-to-product conversion. [94][95][96] CO 2 , the full oxidation product, is likely to obtain under acidic conditions over noble metal-based electrocatalysts (Fig.…”

“…Except for noble-metal-based materials, transitional-metal materials are also promising in oxidizing a series of monohydric alcohols in alkaline solution. 93 Taking Ni-based 2D electrocatalysts as an example, You et al 46 exfoliation method and proved its excellent EOR performance in 1.0 M NaOH. 98 Compared with bulk NiAl-LDH, the exposure of more active site ultrathin LDH nanosheets allowed the higher oxidation current density of the EOR with the presence of 1.0 M ethanol in the electrolyte (543.33 A g −1 at +0.58 V vs. Ag/AgCl), which was 39 times that of the bulk materials (Fig.…”

“…Except for noble-metal-based materials, transitional-metal materials are also promising in oxidizing a series of monohydric alcohols in alkaline solution. 93 Taking Ni-based 2D electrocatalysts as an example, You et al 46 designed a porous Ni 3 S 2 electrocatalyst supported on Ni foam, allowing selective oxidation of ethanol and its derivatives, including ethanol, benzyl alcohol, and furfuryl alcohol. Notably, the oxidized products are not CO 2 , but the corresponding carboxylic acid.…”

Oxygen Vacancies Alter Methanol Oxidation Pathways on NiOOH

“…As an electron-releasing reaction, the methanol oxidation reaction (MOR) is critical to direct methanol fuel cells (DMFCs), which have drawn enormous interest thanks to high theoretical energy density, low working temperature, and low pollutant emission , and might potentially replace conventional lithium-ion batteries in powering automobiles or portable electrical devices . Furthermore, in terms of environmental and synthetic chemistry, electrooxidation has been reported to be an effective method for removing methanol from wastewater , and for producing valuable chemicals like formate. , Notably, the catalyst plays a decisive role in determining the efficiency of MOR catalysis. Monometallic Pt catalysts have been widely used as a catalyst for methanol oxidation which proceeds through established CO-forming mechanisms. , Despite relatively high MOR activity, Pt catalysts are costly and highly susceptible to CO poisoning .…”

Electro-Oxidation Reaction of Methanol over La2–xSrxNi1–y(Mn/Fe/Co)yO4+δ Ruddlesden–Popper Oxides

“…Oxides of nickel (Ni) have emerged as extensively studied transition-metal oxides for electrocatalysis due to their advanced oxygen-ion conductivity, structural diversity, nontoxicity, reduced onset potential, and improved catalytic activity. Research has indicated that the electrocatalytic oxidation of methanol by Ni-based oxides are facilitated by the Ni 3+ /Ni 2+ redox couple, primarily due to the creation of highly active surface-intermediate species known as Ni–OOH. − …”