Selective Facet Engineering of Ni₁₂P₅ Nanoparticle for Maximization of Electrocatalytic Oxidative Reaction of Biomass Chemicals

Abstract

Electrocatalytic hydrogen generation is a prime research topic for the largescale production of hydrogen fuel. High energy demanding oxygen evolution process impedes the production of H 2 at low potentials. Conversion of biomass to value-added chemicals or fuels is appraised as an upcycling process, which is advantageous for resource management. Coupling of hydrogen generation at the cathode with oxidative conversion of biomass to market-demanded chemicals at the anode is a sustainable approach to increase energy efficiency in hybrid electrolysis. For that purpose, Ni-based anode electrocatalysts are in the forefront for ease of formation of hypervalent Ni III species, at a mild anodic potential, which act as an oxidant to propagate the oxidation and dehydrogenation reactions. Herein, we synthesized Ni 12 P 5 nanohexagon via kinetic stabilization of high index 425 { } facets and compared the electrocatalytic activity toward various biomass-derived platform chemicals oxidation with the thermodynamically stable Ni 12 P 5 nanosphere. The Ni 12 P 5 nanohexagon outperforms the current state-of-the-art catalysts regarding mass activity, product conversion, and Faradaic yield. Ease of formation of active species, faster charge transfer, and enhanced adsorption of substrates over 425 { } facets resulted in this superior activity. This shape-directing effects on Ni 12 P 5 ensured potential advantage of 150 mV in hybrid electrolysis over water splitting reaction when ethanol was used as a substrate in a two-electrode electrolyzer cell.

Enhancing Trifunctional Electrocatalytic Activities via Lanthanide Modulation in Fe–Co-Based Double Perovskite Oxides

“…Enlightened from above studies, in this research, we introduce several Fe–Co-based double perovskite oxides (A 2 FeCoO 6 ) tuning the A-site with lanthanides (A = Nd, Eu, Gd, and Dy) as highly active trifunctional electrocatalysts for water oxidation and oxygenation of alcohols toward value-added products for energy-saving H 2 production in basic medium (pH = 14) . Small molecule activation-assisted H 2 generation is a promising strategy to generate H 2 at low energy budget. , As anticipated, the best catalyst comes out to be Eu 2 FeCoO 6 , which shows significant lower oxidation potential for benzyl alcohol oxidation of 1.43 V vs RHE compared to water oxidation potential (1.493 V vs RHE) at 20 mA cm –2 in a 1 M NaOH (pH = 14) electrolyte medium. Moreover, the best catalyst, Eu 2 FeCoO 6 , exhibited a potential advantage as high as 70 mV at 20 mA cm –2 for 0.1 M benzyl alcohol oxidation compared to that of OER.…”