Boosting Hydrogen Evolution by Methanol Oxidation Reaction on Ni-Based Electrocatalysts: From Fundamental Electrochemistry to Perspectives

Abstract

Hydrogen production via electrocatalytic water splitting is hampered by the slow kinetics of the anodic oxygen evolution reaction (OER). To address this limitation, the electrochemical hydrogen evolution reaction (HER) can be boosted with the more favorable oxidation of small organic molecules ideally driven by renewable energies, producing valuable chemicals. In this context, coupling hydrogen production with the methanol oxidation reaction (MOR) with simultaneous formate production has garnered significant interest. Such a cost-effective electrocatalytic process, meeting the growing demand for energy storage and fuel production, requires developing cheap and efficient electrocatalysts. Given the knowledge gap between precious and nonprecious metal electrocatalysts, exemplified by nickel and its derived compounds, this review focuses on MOR from fundamental electrochemistry, materials design and synthesis, and activity-composition/structure relations. Despite significant advances, we still face formidable challenges in deciphering the intricate catalytic mechanism, elevating the activity and selectivity to new heights, and pioneering the development of scalable prototypes.

Ruthenium-doped Ni(OH)2 to enhance the activity of methanol oxidation reaction and promote the efficiency of hydrogen production

“…The active species was first formed under alkaline conditions, the adsorption state was formed after the adsorption of methanol molecules, and finally the product formate was obtained by dehydrogenation. 10,40,42–45…”

“… 9 The complexity of formate synthesis, coupled with its huge demand, ensures that the cost per metric ton of formate is four times that of methanol. 10 However, addressing the activity and high selectivity towards formate in the methanol oxidation reaction (MOR) remains a significant challenge. 11 Therefore, the development of efficient bifunctional electrocatalysts is crucial for the advancement of this field.…”

Metal–organic frameworks (MOFs) for hybrid water electrolysis: structure–property–performance correlation

“…, potential, temperature, pH, and electrolyte composition), and the organic substrate's nature. 68,69 Optimizing these parameters is crucial to enhance the efficiency and effectiveness of electrocatalytic organic oxidation processes with MOFs, enabling the production of high-value chemicals.…”

Electrocatalytic Oxidation of Benzaldehyde on Gold Nanoparticles Supported on Titanium Dioxide

“…Given these factors, substituting the OER with the electrooxidation of some biomass-derivate that have more favorable thermodynamics offers a strategic avenue for more energy-efficient production while also enabling the simultaneous creation of high-value-added biomass-derived chemicals [ 6 , 7 , 8 ]. Organic electrochemical oxidation reactions, including alcohol and aldehyde oxidations [ 9 , 10 ], typically require much lower theoretical thermodynamic potentials than the OER, as evidenced by reactions like the urea oxidation reaction (0.37 V vs. RHE) [ 11 ], hydrazine oxidation reaction (−0.33 V vs. RHE) [ 12 ], ammonia oxidation reaction (0.06 V vs. RHE) [ 13 , 14 ], and glucose oxidation reaction (0.05 V vs. RHE) [ 15 ]. These reactions not only promise greater energy efficiency than OER-based water splitting but also expand the potential applications of electrolytic processes in producing economically significant chemicals derived from biomass products, i.e., having net-zero and even negative CO 2 emissions.…”