Ligand‐Promoted Cooperative Electrochemical Oxidation of Bio‐Alcohol on Distorted Cobalt Hydroxides for Bio‐Hydrogen Extraction

Abstract

Hydrogen is increasingly viewed as a game‐changer in the clean energy sector. Renewable hydrogen production from water is industrialized by integrating water electrolysis and renewable electricity, but the current cost of water‐born hydrogen remains high though. An ideal scenario would be to produce value‐added chemicals along with hydrogen so the cost can be partially offset. Herein, facilitated bio‐hydrogen extraction and biomass‐derived chemical formation from sugar‐derived 5‐hydroxymethyfurfural (HMF) were achieved via the in‐situ transformation of cobalt‐bound electrocatalysts. The cyanide‐bound cobalt hydroxide exhibited a low voltage at 1.55 V at 10 mA cm−2 for bio‐hydrogen production, compared with an iridium catalyst (1.75 V). The interaction between the biomass intermediate and the cyanide ligand is suggested to be responsible for the improved activity.

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

“…In an alternative investigation, Deng et al synthesized CoCo-PBA and applied it to the HMF oxidation reaction. 128 Intriguingly, CoCo-PBA exhibited a current density of 10 mA cm −2 at 1.66 V vs . RHE, whereas HMF oxidation required a lower potential of 1.50 V vs .…”

“…126 In an alternative investigation, Deng et al synthesized CoCo-PBA and applied it to the HMF oxidation reaction. 128 Intriguingly, CoCo-PBA exhibited a current density of 10 mA cm À2 at 1.66 V vs. RHE, whereas HMF oxidation required a lower potential of 1.50 V vs. RHE to achieve the same current density. 128 It is worth noting that the electronic and coordination properties of MOFs have been modulated by introducing different organic ligands, thereby enhancing their performance in HMF oxidation.…”

Advanced electrocatalytic systems for enhanced atom/electron utilization

“…Moreover, the electricity consumption of this system to produce per cubic H 2 gas is 2.2 kW h, which is much lower than that of conventional electrochemical water splitting (4.5 kW h). Wang and co-workers 73 proposed a cyanide (CN) bound cobalt hydroxide, in which the N atoms on the CN group could be utilized to capture the bio-hydrogen atoms on the hydroxyl and aldehyde groups of HMF, obtaining FDCA eventually. This system has become a classic biomass oxidation-assisted HER energy-saving system.…”

Earth‐Abundant Metal‐Based Electrocatalysts Promoted Anodic Reaction in Hybrid Water Electrolysis for Efficient Hydrogen Production: Recent Progress and Perspectives

“…Different from Ni-based materials in which Ni 2+ /Ni 3+ redox couple is considered to be involved in the HMF oxidation, the role of Co 2+ /Co 3+ in HMF oxidation remains ambiguous and needs further exploration. [49] Luo's group recently investigated the relationship of the Co valence state with the selectivity and the reaction pathway of the HMF oxidation. [50] Through experimental tests and DFT studies, it was found that the electrogenerated Co 3+ in the CoO x H y electrode generated under low potential can exclusively oxidize the formyl group into carboxylate in HMF molecules with slow kinetics, which can limit the formation of Co 4+ due to the redox of Co 2+ /Co 3+ couple.…”