Advanced multi-component FeCoCuAlMo intermetallic electrocatalysts for efficient and sustainable hydrogen evolution in alkaline freshwater and seawater.

Electrolyzing seawater to produce hydrogen is a promising sustainable energy production technology. The current non-precious metal-based hydrogen evolution reaction (HER) electrocatalysts demonstrate inadequate catalytic activity and poor stability in seawater electrolyte. Therefore, developing stable and efficient non-precious metal-based HER electrocatalysts is a major challenge for achieving sustainable green energy development. This work reports a multi-component intermetallic catalyst FeCoCuAlMo prepared by arc melting and chemical dealloying methods. The electrocatalytic hydrogen evolution performance of catalysts with varying atomic ratios (FeCoCu) 20 (Al 70 Mo 30) 80 , (FeCoCu) 30 (Al 70 Mo 30) 70 , (FeCoCu) 40 (Al 70 Mo 30) 60 , and (FeCoCu) 50 (Al 70 Mo 30) 50 in alkaline seawater and alkaline electrolyte was studied. The findings indicate that these catalysts primarily consist of AlMo 3 and (Cu 0.35 Fe 0.35 Co 0.3)Al, among which the dealloyed (FeCoCu) 30 (Al 70 Mo 30) 70 exhibits excellent catalytic activity with overpotentials of 137.54 and 116.91 mV at a current density of 100 mA/cm2 in alkaline seawater and alkaline electrolyte, respectively, outperforming most catalysts. Additionally, it demonstrated long-term stability in alkaline seawater and alkaline electrolyte for 250 and 400 h without significant decay at overpotentials of 236 mV and 276 mV, respectively. This improved performance can be attributed to the unique structure of the multi-component intermetallic compound, which provides good thermodynamic stability and synergistic effects among its constituents, thereby enhancing HER performance. Within this multi-component intermetallic compound, AlMo 3 particles serve as the primary conductive medium to accelerate electron transfer, while (Cu 0.35 Fe 0.35 Co 0.3)Al serves as the main active site, resulting in a stable structure that provides the catalyst with high catalytic activity and good stability. Thus, the (FeCoCu) 30 (Al 70 Mo 30) 70 electrocatalyst is a promising candidate for seawater electrolysis aimed at hydrogen production. [Display omitted] • Intermetallic composed of AlMo 3 , Al 5 CuMo 2 , and (Cu 0.35 Fe 0.35 Co 0.3)Al was prepared. • AlMo 3 and (Cu 0.35 Fe 0.35 Co 0.3)Al provide pathways and active sites for the catalyst. • It exhibited an overpotentials of 137.54 mV at 100 mA/cm2 in alkaline seawater. • The catalyst shows excellent durability at overpotentials of 276 mV for 400 h. [ABSTRACT FROM AUTHOR]