Improving electrocatalytic performance of Ni-based catalysts: fuel blend strategy and DFT calculations

This study addresses the electrooxidation behavior of glycerol/glucose (as a fuel blend) at commercial carbon fibers decorated with NiOxHy nanostructures. Blending glycerol with various ratios of glucose results in better fuel utilization (FU) together with a higher turnover number (TON). For instance, using an equimolar (1:1) fuel blend exhibits the highest performance compared to pure fuels (glucose or glycerol) as demonstrated by the oxidation current and negative shift of onset potential, besides a 2-fold improvement of FU and TON at 0.6V. DFT calculations guided the reason behind the observed enhancement to the favorable change of the glucose adsorption mode in the presence of glycerol via hydrogen bonding between glucose and glycerol. The formed hydrogen bonds assist in the elongation of the O-H bond at which oxidation is most likely to occur between (O11 and H12) in glycerol from 0.99 ?, in pure to 1.06 ?, for glycerol/glucose blend. Also, a positive shift of HOMO orbital energy, lower ionization energy for (+2 cation), and more negative energy value are estimated to reflect a higher ability of the blend to form and to donate electrons to the underlying catalyst.

Automated summary

This study investigates the electrooxidation behavior of glycerol/glucose fuel blend on commercial carbon fibers decorated with NiOxHy nanostructures. Blending glycerol with different ratios of glucose improves fuel utilization and turnover number, with the 1:1 blend showing the best performance. Density functional theory (DFT) calculations provide insights into the favorable change of glucose adsorption mode in the presence of glycerol through hydrogen bonding. This enhancement is attributed to the elongation of the O-H bond in glycerol and a higher ability of the blend to donate electrons to the underlying catalyst.