Short-Term Annealing Effect on Hydrogen Evolution Activity of Amorphous Al87Y4Gd1Ni4Fe4

TL;DR

Short-term heat treatment improves hydrogen production efficiency in a metal alloy by forming active nanocrystalline phases.

Contribution

A low-cost, effective method to enhance hydrogen evolution reaction (HER) performance through controlled nanocrystallisation of an amorphous alloy.

Findings

Annealing at 647±2 K forms Al(Gd,Ni,Y,Fe), AlFe2Ni, and GdFe2 nanophases that boost HER activity.

Surface reconstruction and Ni enrichment after annealing increase hydrogen recombination rates.

Annealed alloy shows a hydrogen evolution rate of up to 217.9 mL/(g·min) during reuse.

Abstract

What are the main findings?
Heat treatment at 647±2 K forms Al(Gd,Ni,Y,Fe), AlFe2Ni and GdFe2 phases.Short annealing boosts HER via catalytic AlFe2Ni and GdFe2 nanophases.Surface reconstruction and Ni enrichment increase H* recombination rate.

Heat treatment at 647±2 K forms Al(Gd,Ni,Y,Fe), AlFe2Ni and GdFe2 phases.

Short annealing boosts HER via catalytic AlFe2Ni and GdFe2 nanophases.

Surface reconstruction and Ni enrichment increase H* recombination rate.

What are the implications of the main findings?
Thermal treatment enables controlled formation of active catalytic phases.Short annealing is an effective route to enhance HER performance.Ni-rich reconstructed surfaces promote faster hydrogen evolution.

Thermal treatment enables controlled formation of active catalytic phases.

Short annealing is an effective route to enhance HER performance.

Ni-rich reconstructed surfaces promote faster hydrogen evolution.

This work investigates the structural evolution and electrocatalytic activity of the amorphous metal alloy Al87Y4Gd1Ni4Fe4 during short-term annealing and its effect on the kinetics of the hydrogen evolution reaction (HER) in 1 M KOH. It is shown that a 5 min heat treatment at 647 ± 2 K initiates controlled nanocrystallisation with the formation of AlFe2Ni, GdFe2 and Al(X) (X = Gd, Ni, Y, Fe) phases, which are uniformly dispersed in the amorphous matrix. According to XRD, DSC and HRTEM data, it was established that the formation of intermetallic nanodomains leads to a decrease in charge transfer energy barriers and the appearance of additional active centres of H* adsorption. Electrochemical studies have shown an increase in cathode current density, an increase in i0 by 2–3 orders of magnitude, and a decrease in Rct after annealing, confirming the improvement in HER kinetics. Potentiostatic tests showed an increase in the volumetric hydrogen evolution rate from 35.1 to 106.0 mL/(g·min) during the first immersion and up to 217.9 mL/(g·min) during reuse. SEM/EDS analysis revealed surface reconstruction and Ni enrichment after HER, which contributes to the acceleration of the H* recombination stage. The synergy of the amorphous matrix and nanophases ensures high electrocatalytic activity and stability of the system, making annealed AMA a promising low-cost catalyst for alkaline hydrogen evolution.

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