High-Entropy Alloy Nanosheets for Fine-Tuning Hydrogen Evolution

Abstract

The electrolysis of water is promising for hydrogen production. The development of high-performance and low-cost hydrogen evolution reaction (HER) electrocatalysts is particularly important for the wide application of water electrolyzers. Tuning the hydrogen binding energy (HBE) of materials is an effective way to optimize the HER electrocatalysts, particularly for applications in an acidic environment. Here, we report the discovery of a Pt-free combination, PdMoGaInNi, which has the HBE optimum, via computer-facilitated screening. As the exploratory example of the two-dimensional high-entropy alloy (HEA) for HER, the PdMoGaInNi HEA nanosheets were synthesized to realize the predicted Pt-free combination with optimal HBE. The PdMoGaInNi HEA nanosheets exhibit a high HER activity with low overpotentials of 13 mV at 10 mA cm–2, outperforming commercial Pd/C and Pt/C catalysts. Given the high entropy, lattice distortion, and sluggish diffusion effects of HEA, the PdMoGaInNi shows great long-term durability for at least 200 h in a proton exchange membrane water electrolyzer.

A high-entropy atomic environment converts inactive to active sites for electrocatalysis

“…[1][2][3][4] Compared to traditional alloy electrocatalysts, HEAs, with unique polyelemental arrangements, manifest several exotic structure-activity correlations, enabling the adjustment of catalytic properties with different limitations. [5][6][7][8][9] However, tremendous differences in the reaction kinetics of different metal precursors hinder the nanoscale coalescence of different atoms into a single particle through conventional wet chemical synthesis, seriously limiting the application of HEAs. Recently, the main efforts involving HEAs have focused on developing cost-effective synthesis routes with good control over composition, [10][11][12] size, 13 morphology, [14][15][16] and impurities, including the scanning-probe block copolymer lithography method (SPBCL), 17 the carbothermal shock method (CTS), 18,19 the physical spark discharge method 20 and the dealloying method.…”

Designing strategies and enhancing mechanism for multicomponent high-entropy catalysts

“…2D ultrathin HEAs have also been prepared by simple chemical reduction methods. 54 Combined with computer-facilitated screening, the developed multicomponent PdMoGaInNi HEA nanosheets exhibit a high HER activity with a low overpotential of 13 mV at 10 mA cm −2 , even better than commercial Pd/C and Pt/C. 54 Non-noble metal-based alloy nanoparticles have also been used as a core to decorate noble metal catalysts to enhance the stability and reduce the cost.…”

“…54 Combined with computer-facilitated screening, the developed multicomponent PdMoGaInNi HEA nanosheets exhibit a high HER activity with a low overpotential of 13 mV at 10 mA cm −2 , even better than commercial Pd/C and Pt/C. 54 Non-noble metal-based alloy nanoparticles have also been used as a core to decorate noble metal catalysts to enhance the stability and reduce the cost. For example, Pd can be directly decorated on a non-noble HEA (FeCoNiSn) nanoparticle surface through the galvanic exchange reaction.…”

“…2D ultrathin HEAs have also been prepared by simple chemical reduction methods. 54 Combined with computer-facilitated screening, the developed multicomponent PdMoGaInNi HEA nanosheets exhibit a high HER activity with a low overpotential of 13 mV at 10 mA cm −2 , even better than commercial Pd/C and Pt/C. 54 …”

Dual Function of Hypo-d-electronic Transition Metals in the Brewer Intermetallic Phase for the Highly Efficient Electrocatalytic Hydrogen Evolution Reaction in Alkaline Electrolytes

“…This high electrocatalytic HER activity of Nb 6 Co 7 can be attributed to the low water dissociation energy on the Nb site and the earlier mentioned hypo-hyper d electronic interaction (i.e., dual function). The strategy present in this work may also be applied in other systems such as high-entropy alloys (HEAs) that may further improve the electrocatalytic HER activity under alkaline conditions in the future. , …”