The role of oxygen-vacancy in bifunctional indium oxyhydroxide catalysts for electrochemical coupling of biomass valorization with CO2 conversion

Abstract

Electrochemical coupling of biomass valorization with carbon dioxide (CO2) conversion provides a promising approach to generate value-added chemicals on both sides of the electrolyzer. Herein, oxygen-vacancy-rich indium oxyhydroxide (InOOH-OV) is developed as a bifunctional catalyst for CO2 reduction to formate and 5-hydroxymethylfurfural electrooxidation to 2,5-furandicarboxylic acid with faradaic efficiencies for both over 90.0% at optimized potentials. Atomic-scale electron microscopy images and density functional theory calculations reveal that the introduction of oxygen vacancy sites causes lattice distortion and charge redistribution. Operando Raman spectra indicate oxygen vacancies could protect the InOOH-OV from being further reduced during CO2 conversion and increase the adsorption competitiveness for 5-hydroxymethylfurfural over hydroxide ions in alkaline electrolytes, making InOOH-OV a main-group p-block metal oxide electrocatalyst with bifunctional activities. Based on the catalytic performance of InOOH-OV, a pH-asymmetric integrated cell is fabricated by combining the CO2 reduction and 5-hydroxymethylfurfural oxidation together in a single electrochemical cell to produce 2,5-furandicarboxylic acid and formate with high yields (both around 90.0%), providing a promising approach to generate valuable commodity chemicals simultaneously on both electrodes.

Electrocatalytic Waste-Treating-Waste Strategy for Concurrently Upgrading of Polyethylene Terephthalate Plastic and CO2 into Value-Added Formic Acid

“…In addition, X-ray photoelectron spectroscopy (XPS) was applied to analyze the electronic state of O 1s for Ni­(OH) 2 and Ni­(OH) 2 -V O (Figure d). Apart from the peak of lattice oxygen (529.9 eV), another obvious peak at 531.4 eV can be attributed to oxygen vacancy . Remarkably, for O 1s of Ni­(OH) 2 -V O , the oxygen vacancy accounts for about 57%, much larger than that of Ni­(OH) 2 (31%), further demonstrating its numerous oxygen vacancies.…”

“…Apart from the peak of lattice oxygen (529.9 eV), another obvious peak at 531.4 eV can be attributed to oxygen vacancy. 24 Remarkably, for O 1s of Ni(OH) 2 -V O , the oxygen vacancy accounts for about 57%, much larger than that of Ni(OH) 2 (31%), further demonstrating its numerous oxygen vacancies. For Bi-MOFs-P after in situ electrochemical reconstruction, its XRD pattern matches well with the standard peaks of Bi (JCPDS 45-1344) and Bi 2 O 3 (JCPDS 44−1246), also illustrating the formation of Bi/Bi 2 O 3 heterostructure (Figure 2e).…”

Investigating the role of oxygen vacancies in metal oxide for enhanced electrochemical reduction of NO3− to NH3: mechanistic insights

“…The presence of a prominent peak at 531.8 eV in OV-MoO 3 /Ce, in contrast to OV-MoO 3 , signifies the higher concentration of OVs in the OV-MoO 3 /Ce sample. 57 The high-resolution X-ray photoelectron spectra (HRXPS) of In 3d and O 1s of InOOH showed a similar pattern, 22 where the peak for In 3d5/2 at 444.2 eV in InOOH moves down in binding energy after being exposed to Ar plasma and up in binding energy after being exposed to O 2 plasma (as shown in Fig. 6i).…”

“…17,18 These obstacles arise due to the exceptionally high decomposition energy of the triple bond in N 2 (941 kJ mol −1 ) and the limited solubility of N 2 in water. 19–22 Furthermore, the dissociation of the first bond in NN necessitates an energy input of 410 kJ mol −1 , rendering the activation of N 2 exceptionally challenging and energetically demanding. Similarly, the electrochemical conversion of N 2 to NH 3 faces substantial impediments due to the intense competition posed by the side product, namely the hydrogen evolution reaction (HER), observed across traditional catalysts, such as Rh, Fe, and Ru.…”

Phase Interface Regulating on Amorphous/Crystalline Bismuth Catalyst for Boosted Electrocatalytic CO2 Reduction to Formate

“…15,16 However, the unsatisfied current density and lower formate faradaic efficiency largely hamper their scalable application. 17,18 Among metal-based materials for electrochemical CO 2 reduction into formate, 19,20 Bi-based electrocatalysts have emerged as the most promising candidate. 21,22 In addition to inherent catalytic performance, abundant reserves, and nontoxicity, Bi-based materials also can inhibit the competition of the hydrogen evolution reaction (HER) in the CO 2 reduction process.…”