Linear paired electrochemical valorization of glycerol enabled by the electro-Fenton process using a stable NiSe2 cathode

Metal-Compound-Based Electrocatalysts for Hydrogen Peroxide Electrosynthesis and the Electro-Fenton Process

“…The recent studies of 2e – ORR catalysts often only consider the thermodynamics of the ORR pathways based on the volcano relations (Figure ). However, the kinetic considerations of suppressing the undesired O–O bond cleavage are also important (Figure b), as they laid the foundation for our recent discovery of a series of metal-compound-based new 2e – ORR catalysts. − OOH* can be cleaved thermally across two adjacent active sites or electrochemically via reductive elimination, which can be thermodynamically suppressed by destabilizing O* and/or OH* on the catalyst surface (vide supra). These O–O bond cleavage processes can also be kinetically suppressed by increasing their activation barriers, and one effective strategy is to increase the interatomic distances between neighboring active sites on the catalyst surface.…”

“…Over the past decade, several classes of selective 2e – ORR catalysts, including noble metal alloys, − carbon nanomaterials, − single-atom catalysts, − and metal compounds, − have been studied for H 2 O 2 electrosynthesis under different pH conditions. , Among these reports, alkaline 2e – ORR catalysts have been most extensively studied, despite several limitations in alkaline H 2 O 2 electrosynthesis, including the instability of H 2 O 2 in alkaline solution and the less competitive anion-exchange membrane (AEM) technology . Moreover, carbon nanomaterials already perform quite well under alkaline conditions. , In contrast, the less studied acidic and neutral conditions are attractive for several reasons besides the chemical stability of H 2 O 2 .…”

“…In comparison to the well-studied carbon nanomaterials and noble metal alloys, interest in metal compounds as potential 2e – ORR catalysts for H 2 O 2 electrosynthesis is more recent, and their structure–property relationships are much less understood. By integrating computation and experiment, our recent research established rational catalyst design rules that led to the discovery of a series of binary (CoS 2 , CoSe 2 , NiSe 2 ) and quaternary (CuCo 2‑ x Ni x S 4 , 0 ≤ x ≤ 1.2) earth-abundant metal chalcogenide compounds as robust 2e – ORR catalysts in acidic and neutral solutions, and achieved mechanistic insights into the catalyst selectivity, activity, and stability. In the meantime, other metal compounds have also found success in selective 2e – ORR electrocatalysis and H 2 O 2 electrosynthesis. ,,− Systematic studies of metal chalcogenide catalysts for acidic 2e – ORR have led to significant improvements in both H 2 O 2 bulk electrosynthesis performance and catalyst stability, and the more stable CoSe 2 and NiSe 2 catalysts have been utilized for the electro-Fenton process that is more demanding for catalyst stability.…”

“…By integrating computation and experiment, our recent research established rational catalyst design rules that led to the discovery of a series of binary (CoS 2 , CoSe 2 , NiSe 2 ) and quaternary (CuCo 2‑ x Ni x S 4 , 0 ≤ x ≤ 1.2) earth-abundant metal chalcogenide compounds as robust 2e – ORR catalysts in acidic and neutral solutions, and achieved mechanistic insights into the catalyst selectivity, activity, and stability. In the meantime, other metal compounds have also found success in selective 2e – ORR electrocatalysis and H 2 O 2 electrosynthesis. ,,− Systematic studies of metal chalcogenide catalysts for acidic 2e – ORR have led to significant improvements in both H 2 O 2 bulk electrosynthesis performance and catalyst stability, and the more stable CoSe 2 and NiSe 2 catalysts have been utilized for the electro-Fenton process that is more demanding for catalyst stability. In addition to demonstrating electro-Fenton degradation of an organic pollutant using a CoSe 2 cathode, we further developed a novel approach for electrochemical valorization of biomass-derived feedstock into value-added oxidation products using the electro-Fenton process at a NiSe 2 cathode …”

“…In the meantime, other metal compounds have also found success in selective 2e – ORR electrocatalysis and H 2 O 2 electrosynthesis. ,,− Systematic studies of metal chalcogenide catalysts for acidic 2e – ORR have led to significant improvements in both H 2 O 2 bulk electrosynthesis performance and catalyst stability, and the more stable CoSe 2 and NiSe 2 catalysts have been utilized for the electro-Fenton process that is more demanding for catalyst stability. In addition to demonstrating electro-Fenton degradation of an organic pollutant using a CoSe 2 cathode, we further developed a novel approach for electrochemical valorization of biomass-derived feedstock into value-added oxidation products using the electro-Fenton process at a NiSe 2 cathode …”