Defective Ni3S2 nanowires as highly active electrocatalysts for ethanol oxidative upgrading

Abstract

Electrochemical upgrading of biomass ethanol to value-added chemicals is promising for sustainable society. Here, we synthesize defective Ni 3 S 2 nanowires (NWs), which show high activity towards electrochemical oxidation of ethanol to acetate. The Ni 3 S 2 NWs are formed by the oriented attachment mechanism, and rich defects are introduced during the growth. A low onset potential of 1.31 V and high mass activity of 8,716 mA•mg Ni −1 at 1.5 V are achieved using the synthesized Ni 3 S 2 NWs toward the ethanol electro-oxidation, which are better than the Ni(OH) 2 NWs and the Ni 3 S 2 nanoparticles (NPs). And the selectivity for the acetate generation is ca. 99%. The high activity of Ni 3 S 2 NWs is attributed to the easier oxidation of Ni(II) to the catalytically active Ni(III) species with the promotion from S component and rich defects. These results demonstrate that the defective NWs can be synthesized by the oriented attachment method and the defective Ni 3 S 2 NWs structure as the efficient nonnoble metal electrocatalysts for oxidative upgrading of ethanol.

Defect engineering of Ni3S2 nanosheets with highly active (110) facets toward efficient electrochemical biomass valorization

“…S7†). 26,39,40 The TOF of V s -Ni 3 S 2 (295 h −1 ) is ∼three times higher than that of Ni 3 S 2 -5 h at 1.325 V vs. RHE, and 2.4 times at 1.35 V vs. RHE (Fig. 5a).…”

“…To determine the number of active sites m, CV curves at different scan rates were tested to give a linear relationship and the slope was given by the formula: Slope ¼ n 2 F 2 Sm 4RT , where n is the number of transferred electrons, which is equal to 1 for the oxidation of Ni 2+ to Ni 3+ , and R and T are the ideal gas constant and the absolute temperature, respectively. 26,39,40 Product analysis…”

“…Liu et al 25 reported that oxygen vacancy-rich NiCoMn-LDH exhibited superior ECO of HMF and furfural with high yields (>90%) of the corresponding acid products. Zhang et al 26 claimed that the high activity of defective Ni 3 S 2 nanowires towards electrooxidation of ethanol was ascribed to the synergistic effect of the S component and defect-rich structure, which promoted the easier oxidation of Ni 2+ to catalytically active Ni 3+ species. Despite these achievements, the small current density induced by the competition of the OER still remains a great issue.…”

Replacing Anodic Oxygen Evolution Reaction with Organic ­Oxidation: The Importance of Metal (Oxy)Hydroxide Formation as the Active Oxidation Catalyst

“…21 In most cases, acetate/acetic acid is formed as the major product by 2e ethanol oxidation. 11,24,31,60 Catalysts like highly porous nickel (hp-Ni), 60 FeSn2@nickel foam (NF), 11 defective Ni2S3, 24 etc., have been explored for the selective oxidation of ethanol. The catalysts mentioned above undergo surface modification to form active phase M(O)x(OH)y.…”

“…5,7 In contrast, electrocatalytic oxidation occurs at ambient pressure and temperature producing high conversion efficiency and product selectivity. 5,7 In this context, transition metal-derived electrocatalysts like alloy, [8][9][10][11] phosphide, [12][13][14][15][16] oxide, 17,18 chalcogenide, [19][20][21][22][23][24][25] boride, 26,27 , carbide, 28 nitride, 29 layered double hydroxide, 5 hydrooxide 30,31 etc., have been explored for the oxidation of alcohols (methanol, ethanol, propanol, ethylene glycol, phenol, benzyl alcohol), benzylamine, urea, and biomass-derived intermediates such as cellulose, glucose, furfural, and 5-hydroxymethylfurfural (HMF) into the value-added products. 5,7,32,33 Transition metal-based materials play the role of precatalysts.…”